Drywall Sheet Calculator
Sheet sizes differ by market — 900 × 1800 and 900 × 2400 mm in Korea, 1220 × 2440 mm in North America — so the sheet size is an input. 60 m² with 10% waste is 66 m², and at 2.16 m² a sheet (900 × 2400) that is 30.6, so 31 sheets. One joint appears per sheet width across the run, so area divided by sheet width gives the joint length: 60 ÷ 0.9 = 66.7 m. At 0.35 kg of compound per metre that is 23 kg, with 70 m of tape once the overlaps are counted.
Your numbers
Sheets needed
31
Joint compound
23.3kg
Joint tape
70m
Formula
Sheets needed = ⌈Area × (1 + Waste allowance ÷ 100) ÷ (Sheet width (mm) ÷ 1000 × Sheet length (mm) ÷ 1000)⌉, Joint compound = Area ÷ (Sheet width (mm) ÷ 1000) × Compound per metre of joint
You run out of compound before you run out of board — taping plus a fill and a finish coat can reach 0.5 kg per metre. On ceilings use 12.5 mm board or thicker and buy sheets generously, since overhead work produces far more offcuts.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Area (m²)The space a shape covers — length squared. | 60 | 0 and up |
| Sheet width (mm)The short side of one sheet — it sets how often joints fall. | 900 | 0 and up |
| Sheet length (mm)The long side of one sheet, usually chosen to match the ceiling height. | 2,400 | 0 and up |
| Compound per metre of joint (kg)Compound to tape and finish one metre of joint; three coats can reach 0.5 kg. | 0.35 | 0 and up |
| Waste allowance (%)The extra bought to cover breakage and offcuts. | 10 | 0 ~ 50 |
Step by step
Quick reference table
Results when only Area (m²) changes and everything else stays put.
| Area (m²) | Sheets needed | Joint compound (kg) | Joint tape (m) |
|---|---|---|---|
| 30 | 16 | 11.7 | 35 |
| 45 | 23 | 17.5 | 52.5 |
| 60 | 31 | 23.3 | 70 |
| 90 | 46 | 35 | 105 |
| 120 | 62 | 46.7 | 140 |
What each result means
| Result | At default values |
|---|---|
| Sheets neededSheets to buy; they are not cut down at the till, so this rounds up. | 31 |
| Joint compound (kg)The total weight of joint compound for every joint. | 23.3 |
| Joint tape (m)Joint tape length — the joints plus an allowance for overlaps. | 70 |
Common mistakes
You run out of compound before you run out of board — taping plus a fill and a finish coat can reach 0.5 kg per metre. On ceilings use 12.5 mm board or thicker and buy sheets generously, since overhead work produces far more offcuts.
Glossary
- Area
- The space a shape covers — length squared.
- Sheet width (mm)
- The short side of one sheet — it sets how often joints fall.
- Sheet length (mm)
- The long side of one sheet, usually chosen to match the ceiling height.
- Compound per metre of joint
- Compound to tape and finish one metre of joint; three coats can reach 0.5 kg.
- Waste allowance
- The extra bought to cover breakage and offcuts.
- Sheets needed
- Sheets to buy; they are not cut down at the till, so this rounds up.
- Joint compound
- The total weight of joint compound for every joint.
- Joint tape
- Joint tape length — the joints plus an allowance for overlaps.
Frequently asked questions
Q. How is Drywall Sheet Calculator calculated?
Sheets needed = ⌈Area × (1 + Waste allowance ÷ 100) ÷ (Sheet width (mm) ÷ 1000 × Sheet length (mm) ÷ 1000)⌉, Joint compound = Area ÷ (Sheet width (mm) ÷ 1000) × Compound per metre of joint — Sheet sizes differ by market — 900 × 1800 and 900 × 2400 mm in Korea, 1220 × 2440 mm in North America — so the sheet size is an input. 60 m² with 10% waste is 66 m², and at 2.16 m² a sheet (900 × 2400) that is 30.6, so 31 sheets. One joint appears per sheet width across the run, so area divided by sheet width gives the joint length: 60 ÷ 0.9 = 66.7 m. At 0.35 kg of compound per metre that is 23 kg, with 70 m of tape once the overlaps are counted.
Q. Can you walk through an example?
With Area 60m², Sheet width (mm) 900, Sheet length (mm) 2,400, Compound per metre of joint 0.35kg, Waste allowance 10%, the answer is Sheets needed 31.
Q. What do I need to enter?
Enter Area, Sheet width (mm), Sheet length (mm), Compound per metre of joint, Waste allowance. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Area (m²) moves the answer to Area (m²) 30 → Sheets needed 16 and Area (m²) 120 → Sheets needed 62. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
You run out of compound before you run out of board — taping plus a fill and a finish coat can reach 0.5 kg per metre. On ceilings use 12.5 mm board or thicker and buy sheets generously, since overhead work produces far more offcuts.
Related calculators
Keep your length units consistent across inputs — mixing centimetres and metres throws results far off.