Paint calculator
Enter the room size, doors, windows and number of coats to estimate how much wall paint to buy.
Your estimate
Paint needed
2.4 gal
- Paintable area
- 379 ft²
- Paint per coat
- 1.1 gal
Estimates for planning only — not a quote, survey or financial advice.
How this is calculated
Formula
- Walls = 2 × (length + width) × height − doors − windows
- Paintable area = walls (+ length × width if the ceiling is included)
- Paint = paintable area × coats ÷ coverage × (1 + extra %)
Assumptions
- A door counts as 1.9 m² (20 ft²) and a window as 1.5 m² (16 ft²).
- Coverage varies by product and surface; new plaster and porous or dark surfaces need more. Use the figure printed on the tin.
- Buy the next tin size up from the result.