Paint Calculator
Estimate how much paint you need for a room. Enter room dimensions, number of doors and windows, and coats to get the wall area, litres needed, and number of cans to buy.
Examples
Standard bedroom
A 4 m × 3.5 m bedroom with 2.5 m ceilings, 1 door, and 2 windows, 2 coats.
- Room Length
- 13.123 ft
- Room Width
- 11.483 ft
- Room Height
- 8.202 ft
- Number of Doors
- 1
- Number of Windows
- 2
- Number of Coats
- 2
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How It Works
Formula
Variables, symbols and units
- Room length(m)
- Room width(m)
- Room height(m)
- Number of doors (each assumed 1.89 m²)
- Number of windows (each assumed 1.4 m²)
- Number of coats
- Paintable wall area(m²)
- Paint required (10 m²/L coverage)(L)
Calculation method explained
Enter the room length, width, and height. The calculator computes total wall area, subtracts standard door and window areas, multiplies by the number of coats, and divides by paint coverage (10 m²/L) to estimate litres needed.
References and source material
Examples
Standard bedroom13.123 ft · 11.483 ft → 7
A 4 m × 3.5 m bedroom with 2.5 m ceilings, 1 door, and 2 windows, 2 coats.
- Room Length
- 13.123 ft
- Room Width
- 11.483 ft
- Room Height
- 8.202 ft
- Number of Doors
- 1
- Number of Windows
- 2
- Number of Coats
- 2
- 1 L Cans (Rounded Up)
- 7
Large living room19.685 ft · 16.404 ft → 11
A 6 m × 5 m living room with 2.7 m ceilings, 2 doors, and 3 windows, 2 coats.
- Room Length
- 19.685 ft
- Room Width
- 16.404 ft
- Room Height
- 8.858 ft
- Number of Doors
- 2
- Number of Windows
- 3
- Number of Coats
- 2
- 1 L Cans (Rounded Up)
- 11
Small bathroom refresh8.202 ft · 6.562 ft → 4
A 2.5 m × 2 m bathroom with 2.4 m ceilings, 1 door, 1 window, 2 coats.
- Room Length
- 8.202 ft
- Room Width
- 6.562 ft
- Room Height
- 7.874 ft
- Number of Doors
- 1
- Number of Windows
- 1
- Number of Coats
- 2
- 1 L Cans (Rounded Up)
- 4