Paint Quantity Calculator
Estimates paint quantity needed from wall area, coats and coverage rate.
Enter Values
Minimum 1
Minimum 0.1
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the wall length and height, the number of coats and the paint coverage.
- Press Calculate for the litres needed.
How it works
The wall area is length × height. Multiply by the number of coats and divide by the paint's coverage (m² per litre) to get the litres needed.
Add about 10% for wastage and touch-ups.
Worked example
4 m × 3 m wall, 2 coats, 10 m²/L. Area 12 m² × 2 coats ÷ 10 = 2.4 L.
Common mistakes
- Forgetting to subtract large windows and doors from the wall area.
- Using the wrong spread rate — check the tin; porous or dark-over-light surfaces need more.
Frequently asked questions
How much paint do I need?
Divide the wall area by the paint's spread rate (often 10–16 m² per litre per coat), then multiply by the number of coats.
How many coats of paint should I apply?
Two coats is standard for even colour; strong colour changes or porous surfaces may need a primer plus two top coats.
How many coats do I need?
Two is typical; dark colours over light, or bare surfaces, may need more.
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Cite this tool
Zerdly. (2026). Paint Quantity Calculator. Retrieved from https://www.zerdly.com/tools/paint-quantity-calculator/
Tip: Enter any known values to calculate the remaining results.
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