Drywall Calculator
Calculate drywall step by step: Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.
In short
Calculate drywall step by step: Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.
Formula: Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.
What this calculator does
Calculate drywall step by step: Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉. Worked example, questions and limitations included.
You enter room perimeter, wall height, ceiling area (0 if none) and openings area and a few other details, and the drywall calculator shows the answer along with the working, so you can check it or try other numbers.
The page shows the formula, a numeric worked example, and the assumptions that affect this construction calculation.
Inputs and what they mean
- Room perimeter
- — number value.
- Wall height
- — number value.
- Ceiling area (0 if none)
- — number value.
- Openings area
- — number value.
- Sheet width
- — number value.
- Sheet length
- — number value.
- Waste allowance
- — Enter your own allowance.
How to use it
- Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
- Check the breakdown to see every intermediate step.
- Read the limitations before relying on the result.
Formula
One layer, one side of each wall.
Openings are deducted.
Sheet size is entered.
Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.
Inputs used: Room perimeter, Wall height, Ceiling area (0 if none), Openings area, Sheet width, Sheet length, Waste allowance.
Worked example
4 × 4 m room with ceiling
- Area = 38.4 + 15 − 3 = 50.4 m².
- With waste = 55.44 m².
- ÷ 2.88 = 19.25 → 20 sheets.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Reference price tables
No reference prices are configured. Enter your own prices and rates — this site never assumes them.
Limitations and assumptions
- Single layer.
- No accessories.
- Simple rectangular rooms.
- Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
- The result depends on the values you enter for this drywall calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: OpenStax (Rice University)
Last reviewed:
Common questions
Should I deduct small openings?
Many estimators don't deduct small openings because offcuts are rarely reusable. Enter 0 to be conservative.
What about both sides of a partition?
Double the wall area, or enter twice the perimeter.
Are screws and tape included?
No, only board sheets.
How much waste should I allow?
Around 10% is a common starting point for simple rooms; use 12–15% for many corners, openings or cut-heavy layouts. Set it from your own jobs.
How do I use the Drywall Calculator?
Enter the required values for Room perimeter, Wall height, Ceiling area (0 if none), Openings area, Sheet width, and the other fields shown. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the Drywall Calculator use?
Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.
Sources
Method based on OpenStax (Rice University).
Cite this page
Free Calculator. (2026, November 3). Drywall Calculator. https://freecalculator.tech/tools/drywall-calculator
"Drywall Calculator." Free Calculator, 3 Nov. 2026, https://freecalculator.tech/tools/drywall-calculator.
Drywall Calculator — Free Calculator, https://freecalculator.tech/tools/drywall-calculator
Related tools
Calculate rebar quantity step by step: Bars each way = floor(clear span ÷ spacing) + 1.
Calculate asphalt quantity step by step: Tonnes = length × width × thickness × compacted density × (1 + waste).
Calculate excavation step by step: V = D ÷ 6 × (A_bottom + 4·A_mid + A_top) (prismoidal formula).
Calculate backfill step by step: Compacted fill = excavated − structure volume.
Calculate masonry step by step: Units/m² = 1 ÷ [(L + joint) × (H + joint)].
Calculate framing step by step: Common studs = floor(length ÷ spacing) + 1.