Quick estimate mode — for room dimensions, doors, windows, cost and shopping list:
Full calculator →
Quick Paint Calculator
Enter your wall area and get litres and tins to buy — in seconds.
Your Walls
Add up all walls: width × height for each wall.
Most jobs need 2 coats for even coverage.
Check your paint tin — usually 8–12 m²/L.
Match the tin size you plan to buy.
Result
Tins to buy
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tins
Always buy one extra tin — leftover paint is useful for touch-ups.
Need more detail?
Enter room dimensions, subtract doors and windows, add cost per tin and get a full shopping list.
How to calculate how much paint you need
The formula
Litres needed = (Wall area × coats) ÷ coverage rate
Tins needed = ⌈Litres ÷ tin size⌉ — always round up.
How do I measure wall area?
Measure each wall: width × height. Add them all together. For a quick estimate, subtract about 2 m² per door and 1.5 m² per window.
How many coats do I need?
1 coat — touch-up or same colour. 2 coats — standard for most jobs. 3 coats — painting light over dark, or new plaster.
What coverage rate should I use?
Check the tin label. Most standard emulsions cover 10–12 m²/L. Textured or rough surfaces absorb more — use 8 m²/L.
Pro tip: Buy all tins from the same batch. Colour can vary slightly between batches even with the same colour code.