Example 1 — Living room walls
- 39.6 m²
- 12 m²/L × 2 coats
- pack 2.5 L
6.6 L · 3 packs
A simple one-room scenario — quick sense-check before you buy paint for a standard job.
Paint requirement calculator
Enter the area, paint coverage, and number of coats — we’ll give you litres, full cans, and a rough cost.
Quick shopping estimate: litres from area, coverage, coats, and surface type, then round up to full packs. Still need square footage? Start with wall area. Floors? Floor area. Building a wall? Brick requirement.
Results
Enter data and click Calculate.
How the results are calculated
Litres: (area − openings) ÷ coverage × coats × surface factor.
Packs: ceil(litres ÷ pack size). Example: 6.6 / 2.5 → 3.
Chart: the same litres with 0 / 5 / 10 / 15% buy-extra.
How to use this calculator
- Enter the net area to paint (e.g. 39.6 m² straight from the wall calculator).
- Set paint coverage, number of coats, and surface type.
- If you want, add pack size and price, then hit Calculate.
- You'll see litres needed, pack count, and a chart showing how buy-extra changes the total.
Usage examples
Example 2 — Absorbent surface
- 40 m² @ 10 m²/L × 2
- surface factor 1.15
9.2 L · 4 packs
With an absorbent surface, the extra factor adds up fast — worth checking before you order cans.
Example 3 — With openings
- 50 − 8 m²
- 8 m²/L × 1 coat
5.25 L
Skipping openings you won't paint keeps the buy closer to reality, especially with bigger glazed areas.
Frequently asked questions
Where do the litres come from?
Litres = (area − openings) ÷ coverage × coats × surface factor. Then we round up to full cans.
What’s the surface factor for?
New or thirsty walls soak up more paint. 1.15 means +15% on the result.
Why do packs round up?
You buy whole cans. We divide litres by pack size and ceil — with a tiny floating-point guard so clean ratios don’t jump by one.
What about windows and doors?
Subtract what you won’t paint. Lots of glass? It can save real litres.
What’s the buy-extra chart?
How paint volume changes at 0 / 5 / 10 / 15% spare — for touch-ups and small losses.
Where do I get the wall area?
Easiest: the wall area calculator — paste that here with coverage and coats.
Should I always deduct openings?
For an accurate buy — usually yes. For a rough estimate, some people leave them in as a natural buffer.
What else might help next?
Wall area, skim coat, or primer — if you’re planning the whole finish job at once.