CalculationTime

Drywall Calculator

Estimate plasterboard or drywall sheets from wall length, height, openings, sheet size and waste allowance.

Live math canvas

Your numbers, formula and explanation together

Drywall Calculator: 34 sheet count and square metres. Drywall Calculator uses the declared inputs to produce a transparent default result. Total wall length: 14 m; Wall height: 2.4 m; Openings to subtract: 4 m²; Sheet length: 2.4 m; primary comparison: 14 and 2.4.

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Gross wall area = total wall length × wall height. Net board area = max(0, gross wall area − openings). Order area = net board area × (1 + waste percent ÷ 100). Sheet area = sheet length × sheet width. Sheets = ceiling(order area ÷ sheet area).
  1. Apply the formulaGross wall area = total wall length × wall height. Net board area = max(0, gross wall area − openings). Order area = net board area × (1 + waste percent ÷ 100). Sheet area = sheet length × sheet width. Sheets = ceiling(order area ÷ sheet area).34 sheet count and square metresDrywall Calculator uses the declared inputs to produce a transparent default result. Total wall length: 14 m; Wall height: 2.4 m; Openings to subtract: 4 m²; Sheet length: 2.4 m; primary comparison: 14 and 2.4.

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Total wall length
14 m
Add the lengths of all walls to be sheeted.
Wall height
2.4 m
Use the average height to be covered.
Openings to subtract
4 m²
Total area of large doors, windows or openings not covered by board.
Sheet length
2.4 m
Sheet width
1.2 m
Waste allowance
10 %

Resulting answer

34 sheet count and square metres

Drywall Calculator uses the declared inputs to produce a transparent default result. Total wall length: 14 m; Wall height: 2.4 m; Openings to subtract: 4 m²; Sheet length: 2.4 m; primary comparison: 14 and 2.4.

Answer
34 sheet count and square metres
Live support
Drywall Calculator uses the declared inputs to produce a transparent default result. Total wall length: 14 m; Wall height: 2.4 m; Openings to subtract: 4 m²; Sheet length: 2.4 m; primary comparison: 14 and 2.4.

Assumptions used

What this answer assumes

Board quantity only. Confirm sheet type, thickness, fire/moisture/acoustic rating and fixing requirements before ordering.

  • Wall dimensions and sheet dimensions are entered in metres; openings are entered in square metres.
  • The wall set is treated as flat rectangular surfaces with large openings subtracted.
  • Waste allowance covers cuts, breakage, offcuts, returns and measurement tolerance; it is not a manufacturer or code standard.
  • The result estimates board quantity only. It excludes fasteners, adhesive, joint compound, tape, corner beads, trims, fire/acoustic/moisture ratings, framing checks and local code requirements.
  • Ceilings, double layers and specialist boards should be calculated separately or included deliberately in the wall-length/height inputs.

Master’s Tip

How to use the result well

Master’s Tip: match sheet orientation and sheet length to the room before ordering. A taller wall, ceiling run, horizontal layout or fire-rated assembly can change sheet sizes, waste and the number of joints even when the square-metre total looks right.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Total wall length
14 m
Add the lengths of all walls to be sheeted.
Wall height
2.4 m
Use the average height to be covered.
Openings to subtract
4 m²
Total area of large doors, windows or openings not covered by board.
Sheet length
2.4 m

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Formula

Gross wall area = total wall length × wall height. Net board area = max(0, gross wall area − openings). Order area = net board area × (1 + waste percent ÷ 100). Sheet area = sheet length × sheet width. Sheets = ceiling(order area ÷ sheet area).

Worked example

Gross area = 14 × 2.4 = 33.6 m². Subtract 4 m² of openings to get 29.6 m² net board area. Add 10% waste: 29.6 × 1.10 = 32.56 m². Sheet area = 2.4 × 1.2 = 2.88 m². Sheets = ceiling(32.56 ÷ 2.88) = 12 sheets.

Professional note

Master’s Tip: match sheet orientation and sheet length to the room before ordering. A taller wall, ceiling run, horizontal layout or fire-rated assembly can change sheet sizes, waste and the number of joints even when the square-metre total looks right.

Regional and unit assumptions

Standard or basis: transparent metric area arithmetic for plasterboard/drywall quantity planning. This page does not certify fire resistance, acoustic rating, wet-area suitability, fixing schedule, joint treatment or building-code compliance.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

Gross wall area = total wall length × wall height. Net board area = max(0, gross wall area − openings). Order area = net board area × (1 + waste percent ÷ 100). Sheet area = sheet length × sheet width. Sheets = ceiling(order area ÷ sheet area).

Standard or basis

Standard or basis: transparent metric area arithmetic for plasterboard/drywall quantity planning. This page does not certify fire resistance, acoustic rating, wet-area suitability, fixing schedule, joint treatment or building-code compliance.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: match sheet orientation and sheet length to the room before ordering. A taller wall, ceiling run, horizontal layout or fire-rated assembly can change sheet sizes, waste and the number of joints even when the square-metre total looks right.

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Questions

How do I calculate drywall sheets?

Multiply total wall length by height, subtract openings, add a waste allowance, divide by the area of one sheet and round up to a whole sheet count.

Should I subtract windows and doors?

Subtract large openings when they materially reduce board area. Small cutouts may not reduce the purchase count because offcuts, returns and joint layout still matter.

What sheet size should I enter?

Use the sheet length and width sold by your supplier or specified in the job. A common planning size is 2.4 m by 1.2 m, but longer sheets can reduce joints.

Is plasterboard the same as drywall for this calculator?

For quantity arithmetic, yes. The page estimates sheet area and count. Product name, thickness, edge type and performance rating still need local supplier or specification checks.

Does this include joint compound and screws?

No. It estimates board sheets only. Fasteners, tape, compound, beads, adhesive, trims and finishing materials should be estimated separately.

Calculation note

Drywall and plasterboard estimating is a square-metre problem with sheet-size and joint-layout consequences. The calculator separates wall area, openings, waste and sheet rounding so a quote note can be checked before materials are ordered.

Sheet goods turn area into countable boards

Walls are measured as area, but plasterboard is bought as sheets. Dividing order area by sheet area creates the first count, then the result must be rounded up because partial sheets cannot normally be ordered as exact fractions.

Openings reduce area but not always waste

Large windows and doors can reduce the board area, but they also introduce cuts, returns and offcuts. That is why the calculator subtracts openings first and then applies a visible waste allowance.

Board type matters after the quantity estimate

Moisture-resistant, fire-rated, acoustic and impact-resistant boards can have different specifications and installation rules. Quantity arithmetic should not be mistaken for choosing the correct product or assembly.

Joint layout affects labour and finish quality

Longer sheets may reduce butt joints, while poor layout can create unnecessary seams and waste. A square-metre estimate is a good early check, but a final board order should still be compared with the actual room layout.

Sources and further readingGypsum Association: Technical resourcesUSG: Drywall installation and finishing resourcesNIST: SI Units — Area and length context