Fourteen days booked, and the calendar is lying to you
The leave went in nine weeks ago and it starts on a Saturday. On the back of an envelope there are eleven jobs: lift the old floor in the back room and lay new boards, board the ceiling that came down with it, tile the bathroom, take the fence down and put a patio where the shed was, make good the render on the gable, move two sockets, and a list of small things that will each take an hour and will not. Somewhere in that list is the split you are actually deciding — which lines you do, which lines you buy, and for the lines you do, where the tool comes from.
The reason this decision gets made badly is almost never arithmetic. It is that a fortnight of leave looks like fourteen units of labour, and it is not. Days are not interchangeable. The day the skip arrives is not a working day. The day the electrician is in the house is not a working day for you either, because you are answering questions and moving furniture and cannot start anything that needs the power on. Screed and adhesive and paint take the time they take whether or not you are standing over them, and nothing on the envelope can be brought forward into that gap because the room is occupied by something curing.
So do the subtraction before anything else, on paper, once. It is the only figure on this page that costs nothing to produce and changes every other number that follows. Below is one household's version for that fortnight — not a standard, not a rule of thumb, and not a claim about yours. The point is the shape of the ledger and the fact that it only ever runs one way.
Six days. That is the denominator every other decision on this page divides by, and it is why the first instinct — cram the list, do the lot, hire nobody — fails on the Wednesday of week two rather than at the end. Two of the eleven jobs will take the six days on their own if either goes wrong, and the ones that go wrong are the ones you have never done before. What follows is how to work out which of the eleven are yours, in what order to eliminate them, and what each one drags in behind it in the shape of a tool.
| Where the day goes | Days | Left |
|---|---|---|
| Consecutive days booked off, Saturday to the second Friday | — | 14 |
| The two Sundays that were half the reason for booking it | 2 | 12 |
| Day one: collections, the merchant run, the skip that comes "before noon" | 1 | 11 |
| The two days a trade is in the house and you are fetching rather than working | 2 | 9 |
| Cure, dry and set time that occupies a room and cannot be compressed | 1.5 | 7.5 |
| The second merchant trip, the wrong fixings, and the day it rains on the patio | 1.5 | 6 |
The lines that were never yours to decide
Start by taking things off the list that the arithmetic does not govern, because a cost comparison on a job you are not permitted to do is a waste of an evening. Two separate questions hide here and they have different answers: whether the work needs permission, and whether it needs a particular person. Work can need one, both, or neither, and the pairing is not intuitive.
In a jurisdiction that has adopted the International Residential Code, Section R105.2 lists work exempt from permit, and the list is more generous than most homeowners assume: one-storey detached accessory structures under a stated floor area, fences under a stated height, retaining walls not over four feet measured from the bottom of the footing unless they support a surcharge, sidewalks and driveways within a stated height above adjacent grade, and — the line that covers a good part of the envelope above — painting, papering, tiling, carpeting, cabinets, counter tops and similar finish work. Decks appear there too, but only when they are under a stated area, under a stated height above grade, not attached to the dwelling, and not serving the required exit door, which is four conditions and not one. Read the section as adopted locally rather than as printed, because amendment at adoption is the norm. And read its closing sentence, which is the one that matters: exemption from the permit requirement does not authorise work carried out in violation of the code or of any other local law. The tiling is exempt. The tiling still has to be right.
The second question — who — is where the regimes diverge hardest. In England, Approved Document P to the Building Regulations 2010 narrowed notifiable electrical work in 2013 to three things: a new circuit, replacement of a consumer unit, and any addition or alteration to an existing circuit in a special location, meaning a room containing a bath or shower or one containing a swimming pool or sauna heater. Moving a socket on an existing circuit in a bedroom falls outside that list, which surprises people in both directions. Wales did not simply inherit the English amendment, and Scotland runs an entirely different machine: the Building (Scotland) Act 2003 requires a building warrant before work starts rather than a notice after it, and the Building (Scotland) Regulations 2004 and the Technical Handbooks say what the work must then achieve. Check the Approved Document or Technical Handbook current in your nation; the words "Part P" alone do not tell you the scope. In the United States, NFPA 70, the National Electrical Code, tells you how the installation must be built and says nothing whatsoever about who may build it. That is licensing law, set state by state, and a homeowner permit is common but not universal.
Gas is the clean case: there is no version of this decision where the boiler is yours. The Gas Safety (Installation and Use) Regulations 1998 and HSE's Approved Code of Practice L56 put gas work in the hands of a registered business, and the sensible reading for a householder is that the pipework, the appliance and the flue come off the envelope entirely, permanently, without a comparison being run.
One more gate is easy to miss because it turns on the age of the house rather than the nature of the work. In US target housing built before 1978, the EPA's Renovation, Repair and Painting Rule at 40 CFR Part 745, Subpart E requires certified firms and lead-safe work practices — but its scope is renovation performed for compensation, so a homeowner working on their own dwelling sits outside it. Read that carefully, because it is not permission. It means the containment, the wet methods and the cleaning verification stop being a legal duty at exactly the moment they stop being supervised, in a house with children in it; the EPA's own Renovate Right pamphlet is written for that reader for that reason. The UK equivalent shape is asbestos: the Control of Asbestos Regulations 2012 and HSE's HSG210, Asbestos essentials, govern the artex, the soffit and the old floor tiles, and the sensible answer for anything you suspect is a survey before the crowbar rather than a decision after it.
What your own hour is worth, and what it demonstrably is not
The comparison itself is four numbers: what your materials cost, how long you think it will take you, what you are calling your hour, and the quote for the same scope. Three of the four are yours to be honest about, and the whole exercise stands or falls on the second one.
The reason it falls is that published productivity data does not describe you. The crew outputs in RSMeans, the labour units in the NECA manual and the MCAA labour estimating manual are all derived from trained trades working continuously with their own tools and their own setup, and the CIOB Code of Estimating Practice is explicit that an output is only meaningful alongside the gang and conditions it was measured under. There is no published equivalent for a first-timer, because nobody collects it. So the multiplier between a trade's day and yours is a judgement, and the only defensible way to make it is to have done a small version of the task first. If you have never floated a wall, the honest input is not a number of hours; it is the admission that you do not have one.
The other input people get wrong is the value of the hour, usually by importing their salary. Your salary is what an employer pays for your time in your own trade during working hours. This fortnight is leave: for most people it is not time that could have been sold, and the correct figure is therefore not a wage at all, it is what the fortnight is worth to you as a fortnight. Set it to zero and mean it if the tiling is genuinely how you want to spend a Tuesday — the calculator's own answer for that case is to set it to zero. Set it high if this is the only two weeks of the year the family gets, in which case the arithmetic is being asked to justify spending it in a respirator. Either is defensible. What is not defensible is a number chosen after the fact to make the answer come out the way you had already decided.
And read what the result deliberately excludes. The saving is a cash comparison, and the contractor's price contains things a cash comparison cannot see: public liability cover, a warranty with somebody solvent behind it, their permit handling, and the fact that when the mitred corner is wrong twice it is their material and their Saturday. Against that sits the risk on your side of the ledger, which is not the cost of doing the work but the cost of undoing it — a leak into a downstairs ceiling, a floor lifted twice, or a piece of unpermitted work that surfaces years later when a surveyor or an appraiser asks for the sign-off that was never obtained. That last one is a real number and it lands at the worst possible moment, in the middle of a sale.
- Split the envelope into scopes a trade would actually quote as one job, not into your eleven lines. "Bathroom tiling" is a scope; "grout the splashback" is a task inside it.
- Get one real quote for each scope you are seriously considering handing over. A comparison against a remembered figure or an online average is not a comparison.
- Estimate your hours from the largest sub-task you have personally completed before, then say out loud what you are multiplying by and why.
- Set the value of your hour before you see the result, and write down which of the two cases you are in — a fortnight you would enjoy spending this way, or one you are giving up.
- Run the comparison per scope, never on the project as a whole. The project total hides the one scope where DIY is plainly the wrong answer.
- Add the tool cost from the next two sections to the DIY side before you compare. A saving that evaporates when the hire ticket arrives was never a saving.
Materials plus your hours at whatever you are calling your hour, set against the quote for the same scope. Run it once per scope, and watch what happens to the answer when the hours move by half again — which for a task you have never done is the realistic direction of travel.
Your cost for materials if doing the project yourself.
How many hours you expect the project to take you.
What your time is worth to you — could be your hourly wage, or simply a personal opinion of your time's value.
The all-in quote you received from a contractor for the same work.
Estimated savings by doing it yourself
Needs your Value of Your Time ($/hour)
This page does not assume a price. Enter yours and the answer appears here.
They open the calculator with your figures already in it
DIY vs. Contractor Cost Calculator — 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
- The DIY side here is materials plus hours, and tools are neither. A wet saw, floor sander, scaffold tower or plate compactor is a rental or a purchase you would not otherwise make, and blades, abrasives, adhesive, fasteners and a dumpster for the debris are consumables the contractor has already priced inside the quote. On a one-off job that group can be a quarter of the DIY figure.
- Hours are not the same as weeks. Twenty hours of your own labor spread across weekends is a bathroom out of use for a month and a half where a crew is in and out in a week, and if that means a hotel, a kitchen eaten out of, or a rental that runs longer, the cost lands somewhere this comparison never looks.
Every line that survives is really a tool question
Whatever is left on the envelope now has a tool attached to it, and the tool is not a detail of the job — for several of these lines it is the job. A trade's quote is quietly a quote for access to their van. When you take the line off them you take the van off the price with it, and the gap has to be filled from somewhere.
It helps to sort the tools into four groups before pricing any of them, because only one group is a genuine question. There are tools you already own, where the decision is already made. There are tools cheap enough that the comparison is not worth the hour it takes — a bucket trowel, a grout float, a decent square. There are tools you will use again on the next three jobs, where the honest framing is not hire-versus-buy but whether you want the thing, which is a different conversation and a legitimate one. And there is the fourth group: expensive, specific, used hard for two days and then never, which is the only group the break-even arithmetic is actually for.
Cutting across all four is a gate that no amount of arithmetic gets you through. Some equipment the hire yard will not release without a card — powered access through IPAF's operator scheme, mobile towers through PASMA — and some it will not release to a domestic account at all. That is not a hire company being difficult. Working from a tower or a boom is a competence, and a mobile tower assembled from a manufacturer's instruction manual under BS EN 1004-1 is a temporary works item; a tube-and-fitting scaffold on the front of the house belongs to the scaffolder and to NASC TG20 rather than to you and a weekend. If a line on the envelope needs one of these, it has answered its own question.
| The line on the envelope | What it needs | What actually decides it |
|---|---|---|
| Lifting the old floor and its adhesive | Floor stripper, wheeled | One hard day's use and no second use in sight — the fourth group, and the case the break-even calculation was built for |
| Cutting the new boards | Mitre saw | You want a mitre saw. That is a purchase, and pretending it is a project cost distorts the project |
| Boarding the ceiling on your own | Panel lift | Cheap by the day, absurd to own, and the honest alternative is a second pair of hands rather than a machine |
| Digging out for the patio | Micro excavator and trailer | The tow rating on your licence and the yard's insurance decide this before the day rate does |
| Reaching the gable to make good | Mobile tower | A competence question with a training scheme attached, not a hire question |
| Taking the fence out | Post puller, or a spade and a Saturday | The tool exists but the job does not need it — the cheapest answer on the page is often no tool at all |
Break-even in days, and the lines that move it
For the fourth group the first cut is one division: what the tool costs to buy, over what the yard charges for a day. Below that many days of use, hiring wins on cash; above it, owning does. It is a crude number and it is the right place to start, because it is the only part of the comparison that needs no assumptions at all.
Then correct it, because the sticker and the day rate are both incomplete. Hire yards do not price a week at seven times a day — the tariff structure typically breaks at a week and again at a month, which means a job that runs from Monday to Friday can cost far less than five daily hires and a job that slips into a second week can cost far more than you planned for. Get the yard's own tariff for the actual period; there is no national schedule to look it up in, and any figure quoted in an article would be wrong somewhere. On top of the rate sit the lines that never appear in the headline: delivery and collection, a deposit, the damage waiver, fuel, and the consumables. On a floor stripper or a diamond saw the blades and discs can rival the hire itself, and they are charged as used, so the honest hire cost is not known until the tool goes back.
There is a legal shape to hire worth understanding before you sign the docket, particularly for plant rather than hand tools. The CPA Model Conditions for the Hiring of Plant, the standard terms most of the UK plant industry works to, put the hired item at the hirer's risk while it is out — loss, damage and the hire charges continuing to run — which is why the waiver is offered and why leaving a mini excavator in an unlit front garden is a decision and not an oversight. Read the docket for what happens if the machine is stolen on the Wednesday and what happens if you keep it a day longer than booked.
The buying side has its own missing lines and they cut both ways. Against owning: storage, maintenance, the charger that will not be found in two years, and depreciation. In favour: resale, which for a good tool sold on afterwards can return a real fraction of the purchase price and shortens the true break-even below whatever the division gives you. None of that is publishable as a percentage — a resale figure depends on the tool, its condition and your local market, and nobody publishes a defensible schedule — so the way to use it is to look up what the same model actually sold for recently and subtract that from the purchase price before dividing.
One warning about the denominator, because it is the mistake that costs the most. Break-even days answers "how many days of use before owning is cheaper", and it is only meaningful if you will genuinely accumulate those days. Sixteen days is a persuasive-looking number until you notice that this job uses the thing for two, and the next sixteen days of use are spread over a decade you have not planned. For a tool you will use once, the break-even is irrelevant and the only question is whether you would rather have the tool or the money.
Purchase price over the daily rate gives the day count at which owning stops costing more. Run it with the sticker first, then run it again with resale value subtracted from the price and the yard's weekly rate converted to a per-day figure — the two answers are usually far apart, and the gap is the whole decision.
The cost to buy the equipment outright.
The cost to rent the same equipment for one day.
The hire firm's week rate, if they quote one. Zero means day rate only.
How many days the equipment is actually needed for.
What you expect to sell it for afterwards, if you will.
Break-even rental days
Needs your rates
This page does not assume a price. Enter yours and the answer appears here.
They open the calculator with your figures already in it
Equipment Rental vs. Buy Calculator — 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
- The daily rate is the sticker, not the invoice. Yards add a damage waiver, environmental and fuel charges, and delivery and pickup on anything you cannot carry in a truck, and many bill an eight-hour meter day — run a machine ten hours and it counts as more than one day. Each of those raises the real cost of renting, which moves the true break-even below the day count shown here.
- It assumes the rented machine and the bought machine are the same machine, and at the same price they usually are not. Rental fleets are contractor-grade and built for daily abuse, while the tool a comparable purchase price buys is often a lighter homeowner model with less capacity and a shorter life. Matching the rented machine's specification costs more to buy and pushes break-even further out.
What the day rate is not buying you
A hired tool comes with a return date, and that date does not care about your six working days. The saw goes back on Friday whether or not the rain stopped, and a slipped delivery on Tuesday can turn a two-day hire into a four-day one for reasons that have nothing to do with the tool. Owning removes that coupling entirely: the mitre saw is still in the garage at seven on a Sunday evening, which on a fortnight this tight is worth something the division does not show.
It cuts the other way too. A hired tool is somebody else's maintenance, somebody else's PAT testing, and somebody else's problem when the motor gives up mid-cut — they swap it. An owned tool that fails on the Thursday of week two is a merchant run inside your six days. Neither of these belongs in the arithmetic as a number, and both belong in the decision.
Where the two decisions collide
The split you make does not sit neatly beside the trades' work; it interleaves with it, and that interleaving is where fortnight projects actually come apart. If you take the strip-out and give away the fit, you have made yourself the critical path for somebody else's start date — and a trade who arrives to a room that is not ready either waits, which you pay for, or leaves and comes back in three weeks, which costs you the fortnight. Before committing to a line, ask what is waiting behind it and how much notice that person needs.
Handing over a partly finished job also changes the price of what is left, and not in your favour. A quote for tiling a bare wall is a quote for tiling a bare wall; a quote for tiling over somebody else's substrate carries the risk that the substrate is wrong, and any estimator worth having will either price that risk or exclude it. If you are doing the preparation for a trade to finish, agree in writing what the interface looks like — flat to what tolerance, dry to what standard, and who owns it if it is not.
Two smaller collisions are worth naming because they are cheap to plan and expensive to discover. Waste: on a UK street, putting a skip on the highway needs the highway authority's permission under Section 139 of the Highways Act 1980, and if you instead pay a van to take the debris away, the householder's duty of care under Section 34 of the Environmental Protection Act 1990 means checking they are a registered carrier — fly-tipped rubble traced back to your address is your problem, not theirs. And noise: BS 5228-1 is the code of practice for construction noise and vibration control, with the local authority's powers under Sections 60 and 61 of the Control of Pollution Act 1974 behind it, but on a terraced street the operative constraint is usually simpler and unwritten. A breaker at seven on a Sunday morning buys you a fortnight of difficulty with the people who will still live next door in October.
Cutting the list down to six days
Do the elimination in a fixed order, because every step removes work from the step after it, and doing them in the wrong order means pricing things that were never available to you. What survives the sequence below is the list, and it will be shorter than the envelope.
- Strike everything the regime decides: gas, anything notifiable you cannot self-certify, anything needing a warrant or permit you will not obtain in time, anything behind a suspected asbestos or lead surface that has not been surveyed.
- Strike everything gated by a competence you do not hold — powered access, towers, scaffold, and anything the hire yard will not release to you.
- For each scope that remains, price your own hours honestly against a real quote for the same scope, one scope at a time.
- For each scope you intend to keep, list its tool and put it in one of the four groups. Only the fourth group goes to a break-even calculation.
- Price the fourth-group tools properly: the yard's tariff for the actual period, plus consumables, delivery, deposit and waiver; and the purchase price less realistic resale.
- Add the tool cost back onto the DIY side and re-run the comparison. Some scopes will change sides here, and that is the point of doing it in this order.
- Lay the survivors against six working days, not fourteen, and cut from the bottom until they fit. Then cut one more, because the list has never yet been short enough.
What to settle before the leave starts
The things that decide whether the fortnight produces a finished room or a half-lifted floor, all of them obtainable in the weeks before day one, while every option is still open and nothing has been booked.
- The subtracted day count, written down — Calendar days off, less the days already claimed, the delivery and collection days, the days a trade is in the house, and the cure time that occupies a room. This is the denominator for everything else.
- The permit and notification position for each line, from the authority itself — Which lines are exempt, which are notifiable, which need a warrant before work starts, and which need a person you are not. Obtained from the building department or local authority, not from a forum.
- One real quote per scope, not per task — A comparison needs a live price for the same scope you would otherwise do yourself. A remembered figure or a national average makes the calculation look complete while proving nothing.
- A stated value for your own hour, chosen before you see any result — Zero if the work is how you want to spend the fortnight, high if it is the only two weeks the family gets. Either is honest; a figure picked afterwards to justify the decision is not.
- The hire yard's tariff for the actual period, plus consumables — Daily, weekly and monthly rates break at different points, and blades, discs, fuel, delivery, deposit and damage waiver are charged separately. There is no national schedule to look any of it up in.
- A recent real selling price for any tool you are considering buying — Subtract it from the purchase price before dividing by the day rate. Resale is the single largest correction to a break-even day count and it is never in the sticker.
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.