Paint Calculator
CivilSite.in — tools for Indian construction
Updated
Enter the paintable area, the number of coats and the paint type, and get the litres of paint and primer. The result also converts to 4 L cans and 20 L drums so you can order the cheapest packs.
Paint Calculator
Litres of paint and primer for any wall or ceiling area
Interior emulsion
~11 m²/litre per coat
Wall area = floor perimeter × height. Deduct large openings.
Paint needed
18.2 litres
100 m² · 2 coats · Interior emulsion
Paint
18.2 L
Primer (1 coat)
9.1 L
20 L drums
1
Coverage
11 m²/L
Full order
Paint (L)
18.2
Primer (L)
9.1
4 L cans
5
20 L drums
1
Cost estimate — edit to your local rates
| Material | Quantity | Rate (₹) | Amount |
|---|---|---|---|
| Paint | 18.2 L | /litre | ₹4,545 |
| Primer | 9.1 L | /litre | ₹1,636 |
| Total (materials) | ₹6,182 | ||
Indicative — type today's local rates. Labour is separate: see the material price lists and labour rates.
Buy paint in the largest packs that fit — a 20 L drum is cheaper per litre than four 4 L cans. New plaster drinks the first coat, so add a putty + primer coat before emulsion. Coverage is a guide; the tin states the real spreading rate.
How it works
Paint is sold by spreading rate — how many square metres one litre covers in one coat:
- Paint = area × number of coats ÷ coverage.
- Primer = area ÷ coverage (one coat).
Interior emulsion covers about 11 m²/litre per coat; exterior emulsion is thirstier at ~8; enamel covers more. New plaster soaks up the first coat, so always allow a putty + primer coat first.
Worked example
Paint 100 m² with 2 coats of interior emulsion (~11 m²/L per coat):
- Paint = 100 × 2 ÷ 11 = 18.2 litres
- Primer = 100 ÷ 11 = 9.1 litres
That is one 20 L drum of paint (or five 4 L cans) plus a can of primer.
Coverage by paint type
| Paint | Coverage (per coat) |
|---|---|
| Interior emulsion | ~11 m²/L |
| Exterior emulsion | ~8 m²/L |
| Acrylic distemper | ~9 m²/L |
| Enamel (wood & metal) | ~13 m²/L |
Frequently asked questions
How much paint do I need for a room? Work out the wall area (floor perimeter × height, minus large openings), multiply by the number of coats, and divide by the coverage. For 100 m² in two coats of emulsion, about 18 litres.
How do I calculate wall area for painting? Add up the length of all walls (the room perimeter) and multiply by the ceiling height. Subtract big doors and windows if you want to be precise.
How many coats of paint? Two coats of emulsion over primer is standard. Deep colours or a colour change may need a third.
Is coverage the same for all paints? No — it is printed on the tin and varies with the paint and how porous the surface is. The values here are typical starting points.
Related
CivilSite Editorial Team✓ Engineer reviewed
Written and reviewed by practising civil engineers with 10+ years of Indian residential construction experience.