Paint Calculator

Estimate how much paint you need for a room. Enter wall dimensions, number of coats and the paint's coverage to get the paintable area, litres required and number of tins.

Enter the total wall length and height, the number of coats, the paint's coverage (m² per litre) and how many doors and windows to subtract. The calculator returns the paintable area, litres of paint and tins to buy.

Paintable area
Paint required
Tins to buy

A paint calculator prevents over- or under-buying. Coverage depends on the paint and surface, so use the figure on the tin and round up — it's better to have a little left for touch-ups than to run out mid-wall.

The maths

  • Paintable area = wall area − doors (1.8 m²) − windows (1.4 m²)
  • Litres = area × coats / coverage
  • Tins = ceil(litres / tin size)

Examples

  • 15 m of wall at 2.4 m, 2 coats, 10 m²/L ≈ 6.9 L → 2 tins (5 L)
  • Porous or dark walls need more paint — lower the coverage figure
  • One coat over a similar colour may be enough; two over a contrast

Frequently asked questions

What coverage should I enter?

Manufacturer labels state typical coverage (often 10–12 m²/L per coat). Use the lower end for porous, textured or previously unpainted surfaces.

Should I paint the ceiling too?

Add the ceiling as a separate area (length × width) to your wall length total, or run the calculator twice. This tool covers walls only.

Just for the giggles, much love.
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