Paint Calculator — Litres for any room
Convert wall area into litres of paint needed. Includes door & window deductions and adjusts for number of coats. No signup, instant result.
Quick answer
1 litre of interior emulsion paint covers ~120 sqft per coat on a smooth primed wall. A standard 10×12 ft room with 10 ft ceiling needs about 7.5 litres for 2 coats, after deducting one door and one window.
Room details
Paint needed
7.5litres
For 2 coats on 440 sqft of wall
Wall perimeter44 ft
Wall area (gross)440 sqft
Doors & windows deduction-36 sqft
Net paintable area404 sqft
Litres needed7.5 litres
How paint quantity is calculated
Paint coverage depends on three things: net wall area, number of coats, and paint type. Standard interior emulsion covers about 120 sqft per litre per coat on a primed smooth wall.
Formula: Litres = (2 × (L + W) × H − doors − windows) × Coats ÷ 120
How to use this calculator
- Measure the room's length, width and ceiling height in feet.
- Count the doors and windows — each door deducts ~21 sqft (3×7 ft), each window deducts ~15 sqft (3×5 ft). The calculator does the math.
- Pick the number of coats. Two coats is standard for most interior walls.
- Tick include ceiling if you're painting the ceiling too — the calculator adds the floor-area as ceiling area.
- Round up to the nearest paint-pack size when buying (1L, 4L, 10L, 20L are the common Indian retail sizes).
Coverage by paint type (per litre, per coat)
| Paint type | Smooth wall | Textured / first coat |
|---|---|---|
| Interior emulsion | 120 sqft | 80–90 sqft |
| Premium emulsion (washable) | 110 sqft | 75–85 sqft |
| Distemper | 100 sqft | 70 sqft |
| Exterior emulsion | 90 sqft | 65 sqft |
| Enamel (gloss) | 140 sqft | 100 sqft |
Tips for buying paint
- Always buy 5–10% extra for touch-ups and to cover any patch repairs after the first coat.
- Same-batch matters — buy enough in one lot. Different batches can show colour variation, especially in deep shades.
- Primer is separate — this calculator covers finish paint only. Add primer at the same coverage rate (one coat).
Frequently asked questions
How many litres of paint for a 10x12 room?
A 10×12 ft room with 10 ft ceiling has about 440 sqft of wall area. With 2 coats and standard 120 sqft per litre coverage, you need approximately 7.5 litres of interior paint.
How much area does 1 litre of paint cover?
Standard interior emulsion paint covers about 120 sqft per litre per coat on smooth primed walls. Textured walls or first-coat on raw plaster may need 30–40% more.
How many coats of paint are needed?
Two coats is standard for most interior walls — one for coverage, one for finish. Three coats may be needed when going from a dark colour to a light one, or on porous surfaces.
Should I buy primer separately?
Yes — primer is sold separately and applied as one coat before the finish. Use the same wall area in your calculation, but at one coat instead of two.
What if I'm painting just one wall (accent wall)?
For an accent wall, calculate just that wall's area: length × height. A 12 ft × 10 ft accent wall = 120 sqft, needing about 2 litres for 2 coats.
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