A 12 × 10 ft room with 10 ft walls needs about 7 litres of paint for two coats on the walls — roughly two 4-litre gallons. This free paint coverage calculator works out your paintable wall area, subtracts doors and windows, and gives litres of paint for 1–3 coats at spreading rates matched to your surface.
How much paint do I need for a 10 × 12 room?
Take a 12 × 10 ft room with 10 ft walls. The wall area is 2 × (12 + 10) × 10 = 440 sq ft. Subtract one door (about 21 sq ft) and one window (about 15 sq ft) and you get 404 sq ft of paintable wall — about 37.5 m². At a typical spreading rate of 10 m² per litre, one coat needs 3.75 litres and two coats need 7.5 litres. In Pakistani pack sizes that is two 4-litre gallons, with a little left for touch-ups. Painting the ceiling too? Add the floor area (120 sq ft) and the total rises to roughly 10 litres — two 4-litre gallons plus one 1-litre tin, or one 15-litre drum if you prefer fewer tins.
What is the coverage of 1 litre of paint?
Coverage depends on the paint and the surface. A good plastic emulsion on a previously painted, smooth wall covers about 10–12 m² per litre per coat. Distemper and cheaper emulsions cover less, around 8–10 m²/L. New plaster is porous and thirsty — expect only 6–8 m²/L for the first coat, which is why a sealer or primer coat is standard practice before the topcoats. Exterior weather-shield paints on rough render sit around 7–9 m²/L. Textured walls, heavy roller stipple and spraying all use more paint than the tin's theoretical rate. The calculator's surface-condition presets reflect these ranges; if your paint tin states a different spreading rate, use the closest preset.
How do doors, windows and ceilings change the estimate?
A standard interior door is about 3 × 7 ft (21 sq ft) and a typical window about 3 × 5 ft (15 sq ft) — the calculator subtracts these automatically from the counts you enter. For an accurate job, measure any unusually large openings (sliding doors, full-height windows) and convert them to extra door/window equivalents. Ceilings are often forgotten: a ceiling is the full floor area again, and ceiling paint is usually a flat white distemper or emulsion applied in two coats. Woodwork — doors, frames, skirting — uses enamel or gloss paint, which is estimated separately by the running foot rather than wall area.
How do I use this calculator?
Enter the room's length, width and wall height in feet, the number of doors and windows, and the number of coats — two is the professional standard for a finish coat over a sound surface. Choose the surface condition that matches your walls: new plaster and porous surfaces need the lower spreading rate, which can nearly double the quantity. Tick the ceiling option if the ceiling is being painted. Results show the paintable area, litres required and a suggested combination of 1 L, 4 L and 15 L tins — the pack sizes commonly sold by Pakistani paint brands.
What are the limitations?
This is a planning estimate, not a purchase order. Real consumption rises with porous or damaged surfaces, dark-to-light colour changes (budget an extra coat), textured finishes, and spraying versus rolling. Primer or sealer coats are not included — on new plaster, add a mist or sealer coat at roughly the new-plaster rate. Tin sizes and coverage claims vary between brands (Berger, Dulux, Diamond and others), so check the spreading rate printed on your chosen tin and confirm quantities with your painter before buying. For a whole house, calculate room by room and add about 5–10% for touch-ups and wastage.
Frequently asked questions
How many coats of paint does a room need?
Two finish coats is the standard for walls in good condition. New plaster needs a sealer or primer coat plus two topcoats. Going from a dark colour to a light one usually needs three finish coats, or a stain-blocking primer plus two coats.
Do I need primer before painting?
Yes on new plaster, bare filler patches and drastic colour changes — it seals the surface and improves coverage. On previously painted walls in sound condition you can usually paint directly over them.
What paint tin sizes are sold in Pakistan?
Plastic emulsion is commonly sold in 1 litre, 4 litre (gallon) and 15 litre (drum) packs, with some brands offering other sizes. Enamel paints for woodwork and metal come in smaller tins. Sizes vary by brand, so check before ordering.
Is ceiling paint different from wall paint?
Ceilings usually get a flat white distemper or matt emulsion rather than the washable plastic emulsion used on walls. Estimate it separately — it is the room's floor area — and many painters charge for it as a separate item.
How much extra paint should I buy?
About 5–10% over the calculated quantity covers roller losses, touch-ups and future repairs. Keeping a sealed tin of the exact shade is the cheapest way to fix scuffs later.
Why does new plaster use so much more paint?
Fresh plaster is porous and alkaline — the first coat soaks in instead of forming a film, dropping coverage to 6–8 m² per litre. A sealer coat stabilises the surface so the topcoats spread at their normal rate.
Updated October 2026 · Built and tested by Sharjeel Tahir · How our tools are tested