Home Improvement
How Much Paint Do I Need for a Room?
Measure the walls, apply one formula, and see how many litres common rooms need, plus coverage by paint type and when you need primer.
By Team Vind · Updated · 4 min read
Buy too little paint and you're making a second trip mid-job, hoping the new batch matches. Buy too much and the extra tins sit in the store room for years. Working out the right quantity takes three numbers: the wall area, the number of coats and the coverage printed on the tin.
Step 1: measure the wall area
Wall area = 2 × (length + width) × height − doors − windows
Count about 21 sq ft for each door (3 × 7 ft) and 15 sq ft for each window. For a 12 × 14 ft room with 10 ft walls, one door and two windows: 2 × (12 + 14) × 10 = 520 sq ft, minus 51 sq ft of openings = 469 sq ft.
Step 2: litres of paint
Paint (litres) = area × coats ÷ coverage per litre
At 120 sq ft per litre and 2 coats: 469 × 2 ÷ 120 = 7.8 litres, so buy 8 litres, a 10-litre tin. Painting the ceiling too adds 168 sq ft, making 10.6 litres.
Paint for common rooms
| Room (10 ft walls) | Wall area | Paint, 2 coats | Primer, 1 coat |
|---|---|---|---|
| 10 × 10 ft bedroom | 364 sq ft | 6.5 L | 4 L |
| 10 × 12 ft bedroom | 389 sq ft | 6.5 L | 4 L |
| 12 × 14 ft bedroom | 469 sq ft | 8 L | 5 L |
| 14 × 18 ft living room | 553 sq ft | 9.5 L | 6 L |
Try it: Paint Calculator
Paint Needed
Coverage depends on the paint and the wall
| Finish | Used for | Sq ft per litre per coat |
|---|---|---|
| Distemper | Budget, dry areas | 60–90 |
| Interior emulsion | Most rooms | 100–140 |
| Premium washable emulsion | Living rooms, kids' rooms | 120–160 |
| Exterior emulsion | Outside walls | 50–80 (rough surfaces) |
New plaster and rough walls soak up more paint, so expect the low end of the range. Dark colours over light walls, or light over dark, may need a third coat.
Buying tips
- Buy all the paint for a room in one go, from the same batch, so the shade matches.
- Paint is sold in 1, 4, 10 and 20 litre tins; larger tins cost less per litre.
- Keep half a litre aside for touch-ups.
Plastering first? The plaster calculator works out cement and sand. Building from scratch? See materials for a 1,000 sq ft house.
Frequently asked questions
How much area does 1 litre of paint cover?
About 100–140 sq ft per coat for interior emulsion on a smooth, primed wall; less for distemper and rough surfaces.
How much paint for a 10 × 10 room?
About 6.5 litres for two coats on 10 ft walls with one door and one window.
How many coats of paint are needed?
Two coats for new walls or a colour change; one may be enough when repainting the same colour.
Do I need primer?
Yes on new plaster, putty or patched areas. On a sound, previously painted wall in a similar colour, usually not.
Sources
- Paint manufacturers' technical data sheets (coverage per litre for interior emulsions and distempers)
Last reviewed: 10 October 2026