Paint calculator
Enter m², the data-sheet coverage (m²/l per coat) and coats. You get net litres, litres with waste and buckets to buy, rounded up.
Purchase quantity
3.487 gal
Net measurement: 3.17 gal · Waste 10 %
- Paint needed (net)3.17 gal
- Paint to buy (with waste)3.487 gal
- 3.963 gal buckets1 bucket
Your prices per language/currency. Used when you enable “Use my prices” in calculators. My prices →
Shopping list
What to buy for this calculation. Look up each material at your store.
- 3.963 gal buckets · 1 bucketSearch at Amazon
How it's calculated (visible formula)
net_litres = area ÷ coverage × coats; buy = net × (1 + waste); buckets = ceil(buy ÷ bucket)
- Net geometric measurement, no waste.
- Adjustable waste % for cuts and breakage.
- Purchase rounded up to sellable units (boxes, bags, buckets, boards).
Coverage by surface (matte emulsion, per coat)
| Surface | Per litre |
|---|---|
| Smooth wall (plaster, drywall) | 10 m²/l (≈407 ft²/gal) |
| Textured wall (popcorn, orange-peel) | 7 m²/l (≈285 ft²/gal) |
| Bare brick | 6 m²/l (≈244 ft²/gal) |
| Bare concrete | 8 m²/l (≈326 ft²/gal) |
| Porous render, unprimed | 5 m²/l (≈204 ft²/gal) |
| Primed wood | 9 m²/l (≈367 ft²/gal) |
Worked example: 60 m², 2 coats
- Area: 60 m²
- Coverage: 10 m²/l
- Coats: 2 → 12 l net
- 10% waste → 13.2 l
→ 2 × 15 l buckets (30 l on site, spare for touch-ups).
Common mistakes
- Not deducting doors/windows (use the area calculator).
- Mixing per-coat coverage with total coverage.
- Ordering exact buckets with no touch-up margin.
Use my prices
Your prices per language/currency. Used when you enable “Use my prices” in calculators.
From calculation to quote
Add labour, overhead and your margin, and generate the professional PDF.
FAQs
- How many m² does a litre cover?
- Check the bucket: matte emulsion is typically 8–12 m²/l per coat on a normal surface.
- How many m² does 1 litre cover?
- About 10 m² per coat on smooth walls; about 7 m² on textured walls; about 6 m² on bare brick. Central guide values — always confirm with the bucket and see the surface table.
- How many gallons do I need for a room?
- Wall sq ft ÷ coverage × coats. Example: 430 sq ft at 410 ft²/gal and 2 coats → 2.1 gal net, about 2.3 gal with 10% waste.
- How do I calculate wall square footage?
- Add length × height per wall and deduct doors and windows. The area calculator does it for you.
- How many buckets if they hold 5 gallons?
- Divide gallons with waste by 5 and round up. The calculator uses whatever bucket size you enter.
- How many coats?
- Two is standard for a colour change; one may do for same-colour repaints in good condition.
- Is one coat enough for a repaint?
- Same color in good condition: often yes. Color change: always figure two coats.
- Is bucket coverage per coat or total?
- Per coat: the data-sheet figure (ft²/gal) applies to each coat. That's why the formula multiplies by coats.
- How many gallons of paint for 400 sq ft?
- 400 sq ft ≈ 37 m². At 10 m²/l and 2 coats that's ≈7.4 l net, ≈8.2 l with 10% waste — about 2.2 US gallons. Switch to Imperial above and the calculator shows gallons directly.
- What coverage per surface?
- Smooth drywall 10 m²/l per coat; textured 7; bare brick 6; bare concrete 8. See the surface table — and always confirm with the bucket.
Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.