Woodworking & Construction Calculators
Drywall / Sheetrock Estimator
https://www.woodsizing.com/calculators/drywall-estimator/
Estimate only — not a construction drawing or material takeoff. Verify with a licensed contractor.
Drywall Calculator (Sheets, Tape, Compound)
Wall area is 2(L+W)H minus 20 ft² per door and 15 ft² per window. Ceiling is L×W when included. Sheets are 4×8 ft (32 ft²), counted after waste and rounded up.
Inputs
Results
- Wall area (minus openings)
- 302.0ft²
- Area to buy
- 464.2ft²
- 4×8 sheets
- 15
- Joint tape
- 240ft
- Joint compound
- 4.6gal
The Result is indicative and educational. It does not constitute a design, a technical opinion or medical advice and does not replace calculations or verification by a person with the appropriate qualifications and authorisations. Before purchase, installation or use in practice – in particular in electrical installations – the Result should be verified by a qualified specialist. Details: Terms of Service, point 4.
Example products
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Calculation method
Openings use round figures (20 ft² door, 15 ft² window). A 12×10 ft room, 8 ft high, with one door and two windows has 352 − 20 − 30 = 302 ft² of wall; with the 120 ft² ceiling and 10% waste it is 464.2 ft² to buy, or 15 sheets, 240 ft of tape and about 4.6 gal of compound. Tape and compound are rules of thumb for a three-coat finish.
Exact formula
Tape ≈ 16 ft (about 4.9 m) per sheet. Compound ≈ 1 gal per 100 ft² of area to buy, about 0.4 L per m², for a three-coat finish.
Paint next
The wall area here is the same as the paint calculator’s net area for the same room and openings.
Frequently asked questions
Should I buy 4×12 sheets?
This count is 4×8. For 4×12, divide the area to buy by 48 ft² and round up — not modelled here. Longer sheets mean fewer butt joints to tape.
Why subtract doors?
You do not hang drywall over a door. The 20 ft² credit is a typical 36 × 80 in door. Many hangers skip the credit for small windows, because the cutout is rarely a usable piece; enter 0 windows to do the same.
Metric sheets?
Area converts to m², but the sheet count still assumes 4×8 ft (1.22×2.44 m) sheets. European boards are usually 1.2 or 1.25 m wide, for example 1.2 × 2.6 m (3.12 m²); divide the area to buy by your board’s area and round up.