Drywall Cost Calculator: Sheets & Price Per Room 2026

How drywall cost is worked out

A drywall job has four costs, not one: the sheets, the supplies, the labour and the waste. The gross wall area is 2 times the length plus the width, times the ceiling height — the two long walls and the two short walls. The openings are taken off: one door is 3 by 7 ft, or 21 sq ft, and one window is 3 by 5 ft, or 15 sq ft, and neither is drywalled. The net area is the gross minus the openings. The billable area is the net times 1 plus the waste, and the sheets are the billable area divided by 32, rounded up, because one 4 by 8 ft sheet covers 32 sq ft. The sheet cost is the sheets times the sheet price, the supplies are $0.35 times the net area for the mud, the tape and the screws, and the labour is the labour rate times the net area. The total adds the sheet cost, the supplies and the labour, and the cost per square foot is the total divided by the net area.

At the defaults — 12 by 10 ft, ceiling 8 ft, 1 door, 2 windows, sheet $15.00, labour $1.50/sq ft, waste 10% — the gross area is 2 × (12 + 10) × 8 = 352.00 sq ft, the openings are 21 + 2 × 15 = 51.00 sq ft, and the net area is 352 − 51 = 301.00 sq ft. The billable area is 301 × 1.10 = 331.10 sq ft, so the sheets are 331.10 ÷ 32 = 10.35, rounded up to 11 sheets. The sheet cost is 11 × $15.00 = $165.00, the supplies are $0.35 × 301 = $105.35, the labour is $1.50 × 301 = $451.50, and the total is $165.00 + $105.35 + $451.50 = $721.85 — which is $721.85 ÷ 301 = $2.40/sq ft.

The worked example, line by line

Setup: 12 by 10 ft, ceiling 8 ft, 1 door, 2 windows, sheet $15.00, labour $1.50/sq ft, waste 10%, budget $1,000.

Line 1 — the gross wall area. 2 × (12 + 10) × 8 = 352.00 sq ft.

Line 2 — the openings. 1 door × 21 + 2 windows × 15 = 51.00 sq ft, so the net area is 352 − 51 = 301.00 sq ft.

Line 3 — the billable area and the sheets. 301 × 1.10 = 331.10 sq ft, and 331.10 ÷ 32 = 10.35, rounded up to 11 sheets.

Line 4 — the sheet cost, the supplies and the labour. 11 × $15.00 = $165.00 of sheets, $0.35 × 301 = $105.35 of supplies, and $1.50 × 301 = $451.50 of labour.

Line 5 — the total. $165.00 + $105.35 + $451.50 = $721.85, which is $721.85 ÷ 301 = $2.40/sq ft.

Line 6 — the budget. The cost per net square foot is 1.10 × $15.00 ÷ 32 + $0.35 + $1.50 = $2.365625, so a $1,000 budget covers $1,000 ÷ $2.365625 = 422.72 sq ft of net wall, and a $500 budget covers 211.36 sq ft. The reverse prices the sheets as the billable area divided by 32 without rounding up, so it is an approximation.

Every branch, checked

15 by 12 ft room: the gross area is 2 × (15 + 12) × 8 = 432.00 sq ft, the net is 432 − 51 = 381.00 sq ft, the billable is 381 × 1.10 = 419.10 sq ft, and the sheets are 419.10 ÷ 32 = 13.10, rounded up to 14 sheets. The sheet cost is $210.00, the supplies are $133.35, the labour is $571.50, and the total is $914.85, or $2.40/sq ft. A bigger room costs more in total, but the same per foot, because the sheets, the supplies and the labour all grow with the wall area.

9 ft ceiling: the gross area is 2 × (12 + 10) × 9 = 396.00 sq ft, the net is 396 − 51 = 345.00 sq ft, the billable is 345 × 1.10 = 379.50 sq ft, and the sheets are 379.50 ÷ 32 = 11.86, rounded up to 12 sheets. The total is $818.25, or $2.37/sq ft. A taller ceiling adds wall area, and a taller wall costs a little less per foot, because the sheets are cut to fit and the waste is spread over more feet.

Sheet $20.00: the sheets are still 11, but the sheet cost rises to 11 × $20.00 = $220.00, so the total is $776.85, or $2.58/sq ft. A dearer sheet — a moisture-resistant board, or a board bought at a dear store — adds $55.00 to this room.

DIY labour $0: with no labour, the total is $165.00 + $105.35 = $270.35, or $0.90/sq ft. Doing the labour yourself saves $451.50 on this room, which is most of the job — but only if you can hang and finish the boards to a standard you are happy to live with.

Waste 0%: with no waste, the billable area is the net area, 301.00 sq ft, and the sheets are 301 ÷ 32 = 9.41, rounded up to 10 sheets. The total is $706.85, or $2.35/sq ft. Zero waste saves $15.00 here, but it leaves no board for a miscut or a damaged sheet, so 10% is the safer allowance.

Reverse — the $1,000 budget: the cost per net square foot is 1.10 × $15.00 ÷ 32 + $0.35 + $1.50 = $2.365625, so $1,000 covers 422.72 sq ft of net wall, and $500 covers 211.36 sq ft. A $1,000 budget covers a room a little bigger than 15 by 12 ft with an 8 ft ceiling, and a $500 budget covers a room a little smaller than 12 by 10 ft.

What the defaults assume

The model assumes a rectangular room with flat walls: a room with a curved wall, a sloped ceiling, or a lot of corners changes the wall area, because the drywall is cut to fit. It assumes one door is 3 by 7 ft and one window is 3 by 5 ft: a bigger door or a bigger window takes more off the wall area, so measure the openings if they are not standard. It assumes the sheets are 4 by 8 ft, the supplies are $0.35 a square foot, and the labour is priced by the net wall area. It leaves out the ceiling, the primer and the paint, the trim, and tax — ask the contractor whether the quote includes those. Rounding convention: money is rounded to cents, areas to 2 decimals, sheets are whole numbers rounded up, and all figures are computed from unrounded values, rounded only for display.

Output · formula · meaning

Who uses this

• The homeowner drywalling a bedroom: they learn a 12 by 10 ft room costs $721.85 — $165.00 of sheets, $105.35 of supplies and $451.50 of labour — so they know the exact number before they call the contractor, and they know it is $2.40 a square foot, not a guess.
• The renovator choosing between doing it themselves and hiring out: they learn the labour is $451.50 of the $721.85, and doing it themselves brings the total to $270.35 — so they check whether the $451.50 saving is worth the weekend of hanging and finishing, because the labour is most of the job.
• The landlord drywalling a bigger room: they learn a 15 by 12 ft room costs $914.85 — 14 sheets, $210.00 of sheets, $133.35 of supplies and $571.50 of labour — so they know the bigger room costs the same $2.40 a square foot, and they price the job by the wall area.
• The renovator on a $1,000 budget: they learn $1,000 covers 422.72 sq ft of net wall — so they know the 15 by 12 ft room fits with room to spare, and the 12 by 10 ft room leaves money for the primer and the paint too.

Accuracy & limitations

The math is exact for the numbers you enter: the gross area is 2 times the length plus the width, times the ceiling height, the net is the gross minus the doors and windows, the billable is the net times 1 plus the waste, and the sheets are the billable divided by 32, rounded up. What the model cannot do is measure your room for you: measure the walls, and for a room that is not a rectangle, split it into rectangles, work out each one, and add them together. It leaves out the ceiling, the primer and the paint, the trim, and tax — ask the contractor whether the quote includes those. It assumes one door is 3 by 7 ft and one window is 3 by 5 ft, and that the sheets are 4 by 8 ft. The reverse is an approximation: it prices the sheets as the billable area divided by 32 without rounding up, so a budget that just covers the sheets can fall short by one sheet. For the sizes of the sheets themselves, see drywall sizes chart; for the paint for the same room, see paint cost calculator.