One List, Three Different Answers
A customer in Bristol hands over a list on the doorstep. A double socket in the back bedroom where the desk has moved. Power and light out to a garden office at the end of a 22 m lawn. And the shower point in the family bathroom shifted about 400 mm along the wall so a new screen can go where the old curtain rail was. One visit, one van, one day, one invoice — and under the Approved Document that governs that address, one of those three is not notifiable, one certainly is, and the third depends on a measurement nobody has taken yet.
The instinct is to sort the list by risk, or by size, or by how much of the plaster comes off. None of those is the sorting rule. Notification is a classification question with three axes and no scaling: what class of work is being done, which physical volume of the building it lands in, and which of the four UK nations — or which adopting jurisdiction in the United States — the property sits in. A 22 m armoured run to an outbuilding and a single new lighting circuit in a hallway are the same class. A socket moved 400 mm can change class; a socket moved 4 m across a bedroom cannot.
Getting it wrong in the reader's favour is the expensive direction. Work that was never notified leaves nothing behind — no scheme record, no local authority entry, no compliance certificate — and the absence surfaces years later in a conveyancing enquiry, when the person holding it is a seller under offer with no relationship to whoever did the job. So this is a pricing-stage question, settled before a figure goes out rather than after the boards are up.
It Only Bites on Dwellings
Approved Document P is titled Electrical safety — dwellings, and the second word does the work. The regime reaches electrical installations in dwellings, including the parts of those installations sitting in gardens, in outbuildings within the curtilage, and in the shared amenities of blocks of flats. So the garden office supply is inside the scope even though a lawn is nowhere near a bathroom, and a landlord's stairwell lighting in a converted house is inside it too.
What sits outside surprises people in the other direction. Rewiring a shop, a small office or a village hall carries no building control notification for the electrical work at all. The duty there comes from a different statute — the Electricity at Work Regulations 1989, which imposes an outcome and a standard of competence on the duty holder rather than a notice to anybody — and the installation is designed and certified to BS 7671 exactly as a house would be. Contractors who move between domestic and commercial work often carry the habit the wrong way and either notify something that needs no notice, or assume a mixed-use property is uniformly exempt because most of it is a shop.
Mixed-use is where the boundary has to be drawn on a floor plan. A flat over a commercial unit is a dwelling; the unit is not; the riser serving both is partly each. Where one job crosses that line, split the certification at the boundary and notify the dwelling portion.
Which Document Your Postcode Sits Under
The phrase Part P is used across the trade as though it named one rule. It names a requirement in Schedule 1 to the Building Regulations 2010 that says, in substance, that reasonable provision shall be made in the design and installation of electrical installations to protect persons from fire and injury. The scope of what has to be notified lives not in that requirement but in the Approved Document that supports it — and the Approved Documents diverged in 2013.
In England the 2013 revision cut the notifiable list to three items, and it is short enough to hold in your head: the installation of a new circuit; the replacement of a consumer unit; and any addition or alteration to existing circuits in a special location. Everything else in a dwelling — new sockets, new light points, extended radials, spurs, replacement accessories, a whole kitchen's worth of rewiring on existing circuits — is outside it. Wales did not follow that revision. The Approved Document P applying to Welsh addresses keeps the older, wider scope, in which a kitchen is a listed location and outdoor work is in scope on its own account, so the two garden lights that need no notice in Bristol need one in Newport.
Scotland runs a different machine entirely, and the difference is one of timing rather than of degree. The Building (Scotland) Act 2003 and the Building (Scotland) Regulations 2004 work on a building warrant obtained before work starts, not on a notice given after it, with the technical requirements set out in the Technical Handbooks. Schedule 3 to those regulations lists work that does not require a warrant, and a good deal of domestic electrical alteration sits there — but the standards in the Handbooks apply to the work whether or not a warrant is needed, which is the distinction most often lost in translation. Northern Ireland works to the Building Regulations (Northern Ireland) 2012 and its own Technical Booklets; the position there differs again, and it is a question for the current Booklet rather than for an English summary.
The United States inverts the arrangement. NFPA 70, the National Electrical Code, tells you how the installation must be built and says nothing about whether you may build it or who has to be told. Whether a permit is needed comes from the administrative provisions the jurisdiction has adopted — in an IRC jurisdiction, Section R105, with the exempt list at R105.2. That list is far narrower on the electrical side than a British reader expects, reaching little beyond replacing lamps, connecting approved portable equipment to existing receptacles, and temporary testing systems. Swapping a receptacle, which is emphatically not notifiable in England, is ordinarily permit work there. And adoption lags publication everywhere, so the edition the building department is working to is a question to ask rather than assume.
| The line on the list | England | Wales | IRC jurisdiction, as adopted |
|---|---|---|---|
| Replacing a socket-outlet like for like on an existing circuit | Not notifiable | Not notifiable | Ordinarily permit work; the R105.2 exemptions do not reach it |
| Adding a socket to an existing bedroom circuit | Not notifiable | Not notifiable | Permit, with an inspection before the wall is closed |
| Adding a socket to an existing kitchen circuit | Not notifiable since the 2013 revision | Notifiable — the kitchen is still a listed location | Permit, and the receptacle spacing rules apply regardless |
| Spurring a garden light or an outdoor socket off an existing circuit | Not notifiable | Notifiable — outdoor work remains in scope | Permit, with wet-location requirements on top |
| Moving a shower point inside the space around the shower | Notifiable — alteration in a special location | Notifiable | Permit |
| A new circuit to a garden office, or a new consumer unit | Notifiable | Notifiable | Permit; a service change usually brings the utility in as well |
Where an Alteration Stops Being an Alteration
Everything in the English list except the consumer unit turns on one boundary, and the boundary is defined in BS 7671 rather than in the Approved Document. A circuit is an assembly of equipment supplied from the same origin and protected against overcurrent by the same protective device or devices. Read that literally and most of the grey area disappears. A spur taken off an existing ring is an addition to that circuit. Two extra light points on an existing lighting circuit are an addition to that circuit. A radial extended 6 m to reach a new position is the same circuit, longer. None of them originates at a new protective device, so none of them is a new circuit.
A new way in the board is a new circuit, always, and so is anything that ends up with its own protective device — which catches two cases people file elsewhere. Splitting an overloaded lighting circuit into two, each on its own breaker, creates a circuit that did not exist. So does dividing a ring that has grown past what one device should carry. The customer experiences both as tidying up; the classification treats them as new work, and in England they are notifiable on that ground alone.
The genuinely ambiguous case is the appliance upgrade that drags its protection with it. An 8.5 kW shower replaced by a 10.5 kW unit wants a larger conductor and a larger device: same route, same origin, new cable, new breaker. Whether that is an alteration or the installation of a new circuit is not settled by the words in the Approved Document. In a bathroom it is academic, since the work is in a special location and notifiable either way; elsewhere it is not, and the sound course is to put the question to the scheme's technical line or the building control body and write down the answer with a date and a name against it.
There is a second, quieter route across the boundary, and it is the one that ambushes a fixed price. The addition was going onto the existing circuit because the existing circuit had room. If it does not — if the connected load with the new appliance on it exceeds what that device may carry continuously — then the addition cannot go there, and the job that was a non-notifiable spur becomes a notifiable new circuit before anyone has lifted a floorboard. That is an arithmetic question, and it can be answered on the doorstep with the breaker rating and the appliance nameplates.
Put the protective device rating in with everything the circuit will carry once the new item is on it. The headline answer is the current drawn; the line to read is beneath it, where that current is set against the 80 per cent continuous limit the NEC applies. The ratings and voltages on offer are North American, so a British final circuit is being checked here by analogy — its own answer comes from the device rating and the diversity in the IET On-Site Guide. Either way that percentage is doing double duty: over the line, and the work has changed class from an addition to a new circuit.
The amp rating printed on the breaker in your panel.
Most household outlets in North America are 120V; large appliances (dryers, ranges, EV chargers) are often 240V.
The sum of the wattage of everything plugged into this circuit at once.
Current draw
10 A
- Total connected load
- 1,200 W
- Safe continuous limit (80% rule)
- 16 A
- Safe continuous limit
- 1,920 W
- % of safe continuous capacity used
- 62.5 %
They open the calculator with your figures already in it
Electrical Circuit Load Calculator: 10 A — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 10 A — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- ONE circuit, not the panel. Whether the service and the panel can carry everything together is a separate calculation under the code's demand-factor rules, and a house full of individually compliant circuits can still overload its supply.
- Says nothing about the WIRE. Conductor ampacity is set by the conductor, its insulation, the ambient temperature and how many current-carrying conductors share a raceway — a breaker rating does not guarantee the cable behind it, and a correctly sized breaker on undersized cable is the dangerous combination.
- Voltage drop over the run is not checked here. A circuit inside its current limit can still deliver too little voltage at the far end, which is a separate calculation.
- Motor and compressor loads draw several times their running current at start-up. Nameplate watts describe the running condition and understate what the breaker sees on a cold morning.
- The 80% figure applies to CONTINUOUS loads — three hours or more at full draw. A load that is genuinely intermittent may use more of the breaker's rating, and which of the two a given appliance is can be a judgement.
Code thresholds this tool can check
Code thresholds this tool can check
Checked for United States. Each check below names the body that published the limit it uses. Switching market re-runs them. This is not a code review and has no official standing.
These checks cover only the specific numeric limits listed below. They are not a complete code review: fire separation, egress, structural capacity and accessibility provisions are outside their scope, and only the handful of local amendments offered in the selector are modelled — your municipality may have others. Passing every check here does not make a design compliant. Final approval rests with your local building authority.
The Special Location Is a Volume, Not a Room
The commonest misreading in England is that a bathroom is a special location. It is not. The Approved Document defines the special location by dimension: within a room containing a bath or shower, it is the space around the bath tap or shower head, running vertically from finished floor level to 2.25 m — or to the shower head itself where that is fixed higher — and horizontally either 0.6 m from the edge of a bath tub or shower tray, or, where there is no tray, 1.2 m from the centre point of the shower head. A room containing a swimming pool or a sauna heater is a special location in its entirety. Read the definition in the current edition before relying on the figures; it is a paragraph long and the numbers are in it.
Applied to the list on the doorstep, that is what decides the third line. A shower point moved 400 mm along the wall stays comfortably inside the volume, so the alteration is notifiable. A shaver socket added on the far wall of a large family bathroom, well outside 0.6 m from the bath edge, is not in a special location and the work is not notifiable in England — which sounds wrong to most people and is nonetheless what the document says. In Wales, and in an IRC jurisdiction, that argument does not arise, because neither regime hangs on that particular volume.
None of this touches what may be installed there, and conflating the two is how a non-notifiable job becomes an unlawful one. Section 701 of BS 7671 governs equipment in the zones around a bath or shower — the ingress ratings, the supplementary bonding position, and Regulation 701.512.3, which keeps socket-outlets other than SELV and shaver supply units at least 3 m horizontally from the boundary of zone 1. Those apply whether or not anybody has to be notified. A socket that escapes the special location by 100 mm may still be forbidden by the 3 m rule, and the reasoning that got it out of the notification does nothing at all for it there.
Three Routes to the Same Compliance Certificate
Once the answer is notifiable, there are three lawful ways to discharge it, and they are not interchangeable after the fact. The first is self-certification by a registered competent person: the installer belongs to a scheme authorised under Schedule 3 to the Building Regulations 2010, does the work, tests it, and the scheme notifies the local authority — conventionally within thirty days — while a building regulations compliance certificate goes to the occupier. It is the cheapest and fastest route and it is available only to somebody who was already registered on the day the work was done.
The second is to notify the building control body before starting: a building notice deposited with the local authority, or an application to an approved inspector, followed by whatever inspection regime they specify and a completion certificate at the end. Local authorities generally do not employ electrical inspectors, so in practice they engage one, and the charge reflects that. The route works, but it has to be started at the front of the job — a notice given after the work is finished is not a notice, it is a confession.
The third exists precisely for the installer who is competent but unregistered: third-party certification, in which a registered third party inspects and tests the work and issues the certification. The Approved Document sets conditions on it, and the one that catches people is that the third party has to be engaged before the work begins, so that they can see it at the stages that matter. Ringing round for a third-party certifier once the plaster is on is not a route to anything; nobody can certify what they never saw.
Whichever route is used, keep the two families of paperwork apart in your head, because customers cannot. The certificate you issue under BS 7671 records the design, construction, inspection and testing of the installation work, using the model forms in Appendix 6: an Electrical Installation Certificate where a new circuit was installed, a Minor Electrical Installation Works Certificate for an addition or alteration that did not include one, each with its schedule of test results. That is the electrical document. The building regulations compliance certificate or completion certificate is the other one, it comes from the scheme or the authority rather than from you, and it is the one the conveyancer asks for. A householder handed only an EIC has half the file.
Which is why the fee for the notification belongs on the quotation as its own line, named. Bury it in the labour and the customer who later takes three prices will read yours as expensive against two that quietly assumed nobody would ask.
Signing for One Circuit Means Vouching for the Rest
The thing that makes a small notifiable job disproportionate is not the notice. It is Regulation 132.16 of BS 7671, which says that no addition or alteration shall be made to an existing installation unless it has been ascertained that the rating and the condition of any existing equipment, including that of the distributor, will be adequate for the altered circumstances — and that the earthing and bonding arrangements are adequate too. That obligation attaches to the alteration, not to the notification, so it is there on the non-notifiable spur as well. But the notifiable job is the one where somebody else may read the certificate, and a certificate is a statement that you did ascertain it.
In practice that means the one new circuit to the garden office puts three questions on your desk that have nothing to do with the garden office: whether the main protective bonding is present, correctly sized and actually continuous back to the services it claims to serve; whether the earthing arrangement is what the installation was designed around; and whether the existing supply and board can carry what will now be connected to them. The last of those is the one with a number attached, and the words including that of the distributor put the incoming cut-out inside the question rather than outside it. The equivalent problem in a US jurisdiction is answered from the other end, through the existing-load method of NEC 220.87, which lets recorded maximum demand stand in for a recalculation on an existing dwelling.
If the answer comes back short, the job has escaped this article and become a supply upgrade — a separate application to a network operator who is not notified by building control and never will be, with its own form and its own clock. That is the neighbouring guide's subject, and generation or storage brings its own application under the Energy Networks Association's recommendations G98 and G99 on top. What belongs here is the trigger alone: once demand exceeds what the existing service can defend, the notification is no longer the long pole in the job.
Regulation 132.16 wants a whole-dwelling demand figure in your hand before you sign anything; this one is assembled the American way, on a simplified NEC Article 220 standard method — floor area, the small-appliance and laundry circuits, then the fixed appliance nameplates. Take it as the US-side answer outright, and on a British job as the shape of the question rather than the number, since a UK maximum demand is reached through the diversity tables in the IET On-Site Guide instead. Neither figure means anything until it is set against the rating of the service you are about to certify as adequate.
The total livable floor area of the dwelling used for general lighting load.
20A kitchen/dining small-appliance circuits, each counted at 1500 VA.
Dedicated 20A laundry branch circuits, each counted at 1500 VA.
Sum of the nameplate VA for fixed appliances such as the water heater, range, oven, and dryer.
The nominal service voltage supplying the dwelling.
Estimated required service amperage
38 A
This is a SIMPLIFIED illustrative version of the NEC 220 standard method, omitting several real-world factors (HVAC load, EV chargers, largest motor load addition, optional calculation method). Fixed appliances are carried at 100% because this page takes a VA total and not a count; 220.53 permits 75% where four or more fastened-in-place appliances are present, and a range or a dryer has its own table (220.55, 220.54) that this does not apply. It is NOT a substitute for a complete NEC Article 220 load calculation performed by a licensed electrician, which determines your actual required service size and is required for permitting. Always round up to the next standard breaker/service size (100A, 125A, 150A, 200A) and consult your electrician.
- Total connected load (before demand factor)
- 13,030 VA
- General lighting and receptacles, after the 220.42 factor
- 5,110.5 VA
- Fixed appliances, at 100%
- 4,000 VA
- Demand load
- 9,110.5 VA
They open the calculator with your figures already in it
Home Electrical Service Panel Amperage Sizing Calculator: 37.96 A — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 38 A — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- Amps are not spaces. This sizes the SERVICE and says nothing about the panel's physical capacity — a dwelling can sit comfortably inside 100 A of calculated demand and still need a new panel because every breaker position is taken, the busbar is rated below what is being added to it, or the enclosure will not accept the breaker type the new circuits require. Panels get replaced for spaces at least as often as for amperage.
- The amperage is where the rest of the sizing starts, not where it ends. Service-entrance conductors, the grounding electrode conductor, the meter base, the mast or lateral and the utility's own drop or transformer all follow from this number and none of them fall out of it — and a dwelling service gets its own conductor allowance under NEC 310.12 rather than the general ampacity table, so the wire for a 200 A house is not the wire that table would give it.
- One dwelling unit. A second unit on the same service, an ADU, or a detached garage or workshop on a feeder are not added by piling their loads into these boxes: a multifamily service runs through 220.84's own demand table, and a feeder to an outbuilding is calculated as its own load under 220.40. Stacking two dwellings into this page understates both of them.
When There Is No Spare Way, the Class Changes Again
The second escalation is physical and it costs more than the first. A new circuit needs a way in the board. Where there is not one, the options are a subsidiary board fed from the existing installation, or replacing the consumer unit — and in England and Wales the replacement of a consumer unit is a separately notifiable item in its own right, so a job that was notifiable once has become notifiable twice, with a completely different scope behind the second notice. Scotland asks the warrant question rather than the notice one and Northern Ireland's position is its own Booklet's to state, but the second item costs what it costs in all four.
That scope is where the money goes. A changeover is not a component swap: the whole installation comes into view, every existing circuit is inspected, tested and recorded on the new certificate, and the current edition's residual current and arc-fault provisions land on circuits installed under an older one. Missing bonding, borrowed neutrals and lighting circuits with no protective conductor at the switch drops all surface at that point, each of them a remedial nobody priced. The changeover itself is another guide's subject; what matters here is that the absence of one free module width is what summons it.
So count the ways before the quotation, not on the morning. Two-pole and linked devices take their full width, a surge protective device takes width of its own, and the enclosure that looked half empty through the cover often is not. Where the count comes back at zero and the new circuit is going somewhere self-contained — an outbuilding, a garden room, a garage — the subsidiary board is frequently the honest answer: still one notifiable new circuit, still one certificate, and no obligation to bring a forty-year-old installation up to the current edition to hang a light in a shed.
Count what the board actually has left, with every two-pole device charged at two positions. A result of zero is not a shopping decision — it is the point at which one notifiable circuit turns into a notifiable circuit plus a notifiable board change, and the quotation has to say so.
The total number of breaker spaces the panel provides.
Each single-pole breaker occupies one panel slot.
Each double-pole breaker occupies two panel slots.
Available panel slots remaining
10 slots
The breakers entered need 30 slots against the 40 this panel has. Being inside the rating on this one check settles nothing about the rest of the circuit — the conductors, the overcurrent device, and the work as installed are all outside it.
- Slots used
- 30 slots
They open the calculator with your figures already in it
Electrical Panel Circuit Directory Slot Calculator: 10 slots — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Spaces left is not capacity left. What may be added to a panel is governed by its bus and main breaker rating measured against a calculated load with demand factors applied, not by empty positions. A 100 A panel with twelve free spaces may have no room for a range or a heat pump at all, and filling the spaces anyway is exactly how a bus gets overloaded while every breaker in it holds.
- There is no place here for a three-pole breaker. In a three-phase panel a 3-pole device fills three spaces, and entering it as a double-pole loses one space every time - on a commercial schedule that is several positions gone by the time the count matters. The panel also has a fixed number of positions per phase, which decides where a three-phase load can physically go, not just whether it fits.
- Breaker spaces are not the only thing a panel runs out of. Every grounded conductor needs its own terminal, since NEC 408.41 permits one neutral per terminal, and equipment grounds, AFCI and GFCI pigtails and multiwire circuits eat bar holes faster than they eat positions. A panel with four spaces free and a full neutral bar needs an added bar kit, and the wire bending space in a crowded gutter is a code dimension in its own right.
The Work Is Already Done and Nobody Told Anyone
A large share of the calls that start with this question are retrospective, and they arrive through a conveyancer. Work was done in a kitchen in 2016, there is no certificate, and the buyer's solicitor has raised an enquiry the seller cannot answer. The first job is to establish whether it was notifiable at all, because the enquiry is often raised against work that never needed a notice — a socket added to an existing circuit in an English bedroom needed nothing, and no amount of searching produces a document that was never owed.
Where it was notifiable and was not notified, there are two mechanisms and they are frequently confused. The Building Regulations 2010 provide an application for unauthorised building work, submitted to the local authority after the fact, which normally requires enough opening up for the authority to satisfy itself — and which the authority is not obliged to grant. Separately, the Building Act 1984 carries the enforcement teeth: section 35 makes contravention an offence, and section 36 gives the authority power to require offending work to be removed or altered, exercisable within twelve months of completion of the work. That twelve-month limit is why very old undocumented work is a conveyancing problem rather than an enforcement one.
Which is what the indemnity policy the buyer's solicitor offers is actually addressing. It insures against enforcement action; it says nothing about whether the installation is safe, and it will not survive the policyholder approaching the local authority to ask. It is a transaction lubricant, not a technical outcome, and a seller should understand which of the two they have bought.
The other substitution to resist is offering an EICR in place of the missing paperwork. A condition report is a valuable thing and it will tell everybody whether the installation is safe today, but it is a report on condition, not a record that particular work complied with the Building Regulations when it was carried out, and a careful conveyancer knows the difference. Offer it for what it is worth — evidence about the installation — and be clear that it does not close the enquiry it was asked to close.
Settling It Before the Price Goes Out
All of that is a survey, and it takes about twenty minutes with a torch, a phone camera and the customer's list. The output is not a yes or a no; it is a line-by-line classification with the escalation triggers checked, so the price you send reflects the job the paperwork will describe rather than the job described on the doorstep.
Write the classification down and keep it. Where a scheme technical line or a building control officer gave you a view on an ambiguous line, record the date and the name alongside it. Notification scope changed in England inside living memory and did not change in Wales, and a file note from the day is worth more three years later than a recollection of what the rule used to be.
- Establish the nation first, and for an English address the edition current at the date of the work — for a retrospective enquiry that is the date it was done, not today.
- Confirm the property is a dwelling for these purposes, and where it is mixed-use, mark on the plan where the dwelling portion of the installation stops.
- Classify every line on the list as a new circuit, an addition or alteration, a replacement, or a consumer unit change.
- For each addition, test whether the existing circuit still carries the load with the new item on it; if it does not, reclassify that line as a new circuit.
- Measure the special location where a bathroom is involved — floor to 2.25 m, and horizontally from the tub edge or shower head — and note which side each accessory lands.
- Count the free ways with two-pole devices charged at full width, and decide now between a subsidiary board and a changeover.
- Confirm main protective bonding is present, sized and continuous, and assemble the whole-installation demand figure Regulation 132.16 requires you to have ascertained.
- Choose the route, engaging a third-party certifier before the start if that is the one, and put its fee on the quotation as a named line.
The classification sheet, filled in before the quotation
Every line here is settled at survey stage or it is settled by somebody else later, at your expense. Three of them are arithmetic and the rest are observations, and none of them can be recovered once the work has started.
- The governing document, named, with its edition and its date — England, Wales, Scotland or Northern Ireland, and for retrospective work the edition current when the work was done rather than now.
- Each line of the customer's list classified — New circuit, addition or alteration, replacement, or consumer unit change — the four classes that decide everything downstream.
- The existing circuit's remaining continuous capacity — The number that decides whether an addition stays an addition; over the line and the job is a new circuit before anyone starts.
- The special location measured, not assumed — Vertical to 2.25 m and horizontal from the tub edge or shower head, with each accessory position marked inside or outside it.
- Free ways in the board, two-pole devices at full width — Zero free ways turns one notifiable item into two, and brings every existing circuit into scope with the second.
- Whole-installation demand against the existing service — Regulation 132.16 puts the distributor's equipment inside the question, so the cut-out rating belongs on this sheet too.
- Main protective bonding: present, sized, and proved continuous — Tested rather than looked at — a clamp on a pipe interrupted by a plastic section reads as a bond and conducts nothing.
- The notification route chosen, and its fee as a named line — Self-certification, building notice, or third-party certification — the third has to be engaged before work starts, not found afterwards.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.