Paint Calculator
Calculate exactly how many litres or gallons of paint you need for any room. Add multiple rooms and get your total in one click.
🎨 Calculate Paint Needed
Enter your room dimensions. Add multiple rooms for a whole-house estimate.
How Much Paint Do You Need?
Buying too little paint means an extra trip to the hardware store — and risking a colour mismatch if the batch is different. Buying too much wastes money and leaves you with cans to store or dispose of. Our Paint Calculator takes the guesswork out by calculating the exact amount of paint needed based on your room dimensions, ceiling height, number of coats, and paint coverage rate.
Understanding Paint Coverage
Paint coverage is the area one litre (or gallon) of paint covers in one coat. Most standard interior paints cover 10–14 m² per litre (approximately 400 sq ft per gallon). Premium paints may cover slightly more. Always check the coverage rate on the specific paint tin you plan to buy, as it varies by brand and finish.
Number of Coats
Most painting jobs require two coats for even, opaque coverage — especially when changing colours or painting over bare plaster. One coat may be sufficient for touch-ups or when using high-coverage paint. Three coats are sometimes needed for very dark colours or dramatic colour changes from light to dark.
Tips to Avoid Waste
- Always buy one tin more than calculated — better to have leftover for touch-ups than run short mid-wall.
- Note the batch number on your tins — slight colour variations between batches are common.
- Use a paint calculator per room, not for the whole house at once, for the most accurate estimate.
- Factor in doors and windows — a standard door is approximately 1.8 m², a window 1.4 m².