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Drywall Finish Level Compound Calculator

Joint compound by GA-214 finish level, from joint lengths and coat counts, with the Level 5 skim carried across the whole surface, not just the seams.

Drywall is plasterboard in the UK and Australia.

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SettingsSettings for this calculationUS
Market
Imperial · sales tax
Who is doing the work?

Waste is set to 15% by hand. Pick a tier above to replace it, or keep your own figure.

The whole boarded surface, walls and ceilings together.

Only Level 5 uses this figure for compound, because only Level 5 covers the whole surface. At every other level it serves as the sanity check on your joint lengths and as the basis for the sanding area reported below.

Total length of joint between the factory-tapered board edges.

The taper gives the compound somewhere to sit, so a flat joint finishes level with the board without being floated wide. This is the cheapest joint on the job and the one a good board layout maximises.

Total length of joint between cut board ends, where there is no taper.

A butt joint has no recess, so the compound has to be floated wide enough that the hump it forms is invisible under grazing light. That is why it carries roughly double the rate of a tapered joint here, and why butt joint backing is worth its cost on a ceiling.

Total length of internal corners between two boarded planes.

Wall to wall and wall to ceiling. Angles take less compound than flats because each leg is narrow, and GA-214 asks for one fewer separate coat on them at Level 4 than it asks for on flat joints.

How many screw or nail heads the finish has to conceal.

Individually tiny and collectively significant, because at Level 4 each one is spotted three separate times. They are also the item most often left out of a take-off entirely, which is part of why compound runs short near the end of a job.

Total run of corner bead, edge trim and other accessories to be coated.

External corners, bullnose, L and J trims and expansion beads all get the same number of separate coats as fastener heads under GA-214. A bead's flange is wide, so this line consumes more than its length suggests.

The rung the specification names, which decides how many times each surface is passed over.

The levels are not a quality ladder to be climbed at will — each is matched to a decoration. Specifying Level 5 under a heavy texture wastes a skim coat nobody will see, and specifying Level 4 under a gloss paint in raking light produces exactly the joint photographing the skim exists to prevent.

Extra to cover what is scraped off, left in the pan and lost to sanding.

Finishing is a subtractive trade: a large share of what goes on the wall comes straight back off on the knife, and more of it leaves as dust. Fifteen percent is a common working figure and a heavily sanded Level 5 justifies more.

Joint compound needed

11.5 gal

Medium confidence

The coat counts come from GA-214; the compound per coat is a declared rule of thumb, stated in the sources as the bead width and thickness it represents. A crew that floats wider than that will use more, and the honest way to calibrate this page is against your own last job.

Before the waste allowance
10.01 gal
Coats over flat and butt joints
3 coats
Coats over interior angles
2 coats
Coats over fastener heads and accessories
3 coats
Skim over the whole surface
0 gal
Seam and joint work alone
10.01 gal
Surface to sand
583.5 ft²
Ready-mixed compound by weight
157.85 lb
Then change the inputs to see how far the answer moves.

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How this was calculated

Formula source(s)

  • GA-214 Recommended Levels of Finish for Gypsum Board — the coat counts applied here. Level 1 beds the tape only; Level 2 adds one coat on fastener heads and accessories; Level 3 adds one separate coat over joints and angles and two over heads and accessories; Level 4 puts two separate coats over flat joints, one over interior angles and three over heads and accessories; Level 5 repeats Level 4 and adds a skim coat over the entire surface
  • ASTM C840 Standard Specification for Application and Finishing of Gypsum Board — joint treatment, the requirement that each coat extend beyond the one below it, and the surface preparation the levels describe
  • Compound per metre of joint per coat is a RULE OF THUMB, given here as the bead it stands for: a flat joint at 0.06 L/m (a 120 mm band averaging 0.5 mm), a butt joint at 0.12 L/m floated about twice as wide, an interior angle at 0.045 L/m, a fastener head at 0.6 mL and an accessory leg at 0.10 L/m
  • The Level 5 skim allowance of 0.35 L/m² is also a RULE OF THUMB — roughly one extra 4.5 gal (17 L) box per 500 sq ft (46 m²) of skimmed surface, which is a 0.35 mm average film once the skim has been knifed back
  • Weight is restated from the published net weight of a 4.5 gal box of all-purpose ready-mixed compound, 61.7 lb over 17.03 L, giving about 1.64 kg per litre

Inputs used

Gross Wall and Ceiling Area
1290 sq ft
Tapered Flat Joint Length
295 ft
Butt Joint Length
66 ft
Interior Angle Length
195 ft
Fastener Heads to Cover
900
Accessory Run
82 ft
GA-214 Finish Level
Level 4 — two coats on flats; flat paint, light texture, light coverings
Waste and Sanding Loss Allowance (%)
15

Intermediate steps

Before the waste allowance
10.01 gal
Coats over flat and butt joints
3 coats
Coats over interior angles
2 coats
Coats over fastener heads and accessories
3 coats
Skim over the whole surface
0 gal
Seam and joint work alone
10.01 gal
Surface to sand
583.5 ft²
Ready-mixed compound by weight
157.85 lb
Safety / waste buffer appliedWaste and sanding loss (+15%)
Final result11.51 gal

Confidence note: The coat counts come from GA-214; the compound per coat is a declared rule of thumb, stated in the sources as the bead width and thickness it represents. A crew that floats wider than that will use more, and the honest way to calibrate this page is against your own last job.

What this calculation does not cover

  • Ready-mixed all-purpose compound. Setting-type powder is rated dry and is not comparable volume for volume.
  • Texture, veneer plaster and skim-coat plaster products are separate materials with their own coverage rates.
  • Tape, corner bead, primer and the Level 5 primer-surfacer alternative are not included.
  • The rates are calibrated against an ordinary board layout; a heavily cut-up room uses more per unit of area.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

295 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Sources checked 2026-08-30 · in the site-wide review of 2026-09-06 · v1.0.0

Regulatory standards & verification citations5
  1. GA-214 Recommended Levels of Finish for Gypsum Board — the coat counts applied here. Level 1 beds the tape only; Level 2 adds one coat on fastener heads and accessories; Level 3 adds one separate coat over joints and angles and two over heads and accessories; Level 4 puts two separate coats over flat joints, one over interior angles and three over heads and accessories; Level 5 repeats Level 4 and adds a skim coat over the entire surface
  2. ASTM C840 Standard Specification for Application and Finishing of Gypsum Board — joint treatment, the requirement that each coat extend beyond the one below it, and the surface preparation the levels describe
  3. Compound per metre of joint per coat is a RULE OF THUMB, given here as the bead it stands for: a flat joint at 0.06 L/m (a 120 mm band averaging 0.5 mm), a butt joint at 0.12 L/m floated about twice as wide, an interior angle at 0.045 L/m, a fastener head at 0.6 mL and an accessory leg at 0.10 L/m
  4. The Level 5 skim allowance of 0.35 L/m² is also a RULE OF THUMB — roughly one extra 4.5 gal (17 L) box per 500 sq ft (46 m²) of skimmed surface, which is a 0.35 mm average film once the skim has been knifed back
  5. Weight is restated from the published net weight of a 4.5 gal box of all-purpose ready-mixed compound, 61.7 lb over 17.03 L, giving about 1.64 kg per litre

Which documents these citations point at

Standards referenced: ASTM C840 (ASTM International, United States).

Cite this page

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Tools and safety for this job

To tape and finish joints. Generic types, no brands, no prices.

Protection this work requires

  • Joint-compound dust is very fine and travels: a P1/FFP1 mask is the minimum, and a damp-sponge finish avoids most of it.
Show the 5 tools this job needs

Essential

  • Pole sander

  • Taping knives and mud pan

Recommended

  • Corner trowel

  • Dust extractor or vacuum with a fine filter

  • Mixing bucket or tub

Also needed as materials: sanding screens or paper.

what each drywall tool is for, and the spec that decides which to buy where one does.

At Level 4 the work is all in the seams: 37.9 L (10.0 gal) of compound over roughly 54 m² (583 sq ft) of floated band. Moving up to Level 5 would add a skim over the whole surface — on this job about 41.9 L (11.1 gal) more, and every square metre of it to sand.

Now that you have the number

These guides cover the work this quantity is for — the first ones run this calculator inside the section that raises the question.

Called something else where you work? Self-levelling compound — the term in each market, how close the equivalence really is, and the standard that governs it.

Worked example: Basement room drywall — step 9 of 10

How to calculate drywall finish level compound in 9 steps

  1. Gross Wall and Ceiling AreaThe whole boarded surface, walls and ceilings together.
  2. Tapered Flat Joint LengthTotal length of joint between the factory-tapered board edges.
  3. Butt Joint LengthTotal length of joint between cut board ends, where there is no taper.
  4. Interior Angle LengthTotal length of internal corners between two boarded planes.
  5. Fastener Heads to CoverHow many screw or nail heads the finish has to conceal.
  6. Accessory RunTotal run of corner bead, edge trim and other accessories to be coated.
  7. GA-214 Finish LevelThe rung the specification names, which decides how many times each surface is passed over.
  8. Waste and Sanding Loss Allowance (%)Extra to cover what is scraped off, left in the pan and lost to sanding.
  9. Joint compound neededThe tool computes the joint compound needed from those figures and shows the formula, its sources, and a confidence rating alongside it.

Frequently asked questions

Why does Level 5 need so much more compound than Level 4?
Because it stops being a joint treatment and becomes a surface treatment. Levels 1 through 4 put compound only where there is a seam, a fastener or a bead; Level 5 adds a thin coat across every square metre of board, so the quantity scales with the room's area rather than with the length of its joints.
Is a higher finish level always better?
No — each level is matched to a decoration, and mismatching costs money in one direction or credibility in the other. A heavy texture hides everything a skim coat would have achieved, so Level 5 beneath it is wasted. Gloss paint in raking light shows every joint a Level 4 finish leaves, which is the failure the skim exists to prevent.
Where do the compound rates come from?
They are declared rules of thumb, and the sources state each one as the bead it represents — a width and an average thickness — so you can see what has been assumed. Applied to an ordinary board layout they reproduce the published coverage of a standard box of all-purpose compound at a three-coat finish, which is the only published anchor available for a quantity this variable.
Why is the sanding area reported separately?
Because it drives the labour, the dust control and the programme, and at Level 5 it is a different quantity entirely. Below Level 5 you sand a band along each joint; at Level 5 you sand the whole room. That change, rather than the extra material, is usually what people underestimate.
Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.