Paint calculator

Measure a room or individual walls, deduct doors and windows, choose your coats and the coverage printed on your tin, and see litres required and whole cans to buy.

How the calculation works

Wall area is 2 × (length + width) × height, less entered openings. Litres = net area × coats ÷ coverage per litre × (1 + allowance / 100). Ceiling paint is calculated separately.

Measurements and packaging

• Room mode uses length, width and wall height. Walls mode lets you measure each wall separately.
• Openings are subtracted from the wall area and cannot reduce it below zero.
• Coverage is how many square metres one litre covers per coat. The default of 10 m² per litre is only an illustration; use the figure from your product.
• Extra allowance covers touch-ups and uneven absorption (default 5%).

Worked example

A 4 × 3 m room with 2.5 m walls has 35 m² of wall area. Two coats at 10 m²/L and 5% extra require 7.35 L, or two 5 L cans.

Frequently asked questions

Can I calculate without creating an account?

Yes. Calculations and locally saved projects need no registration. Saving is optional; results are available before creating a project.

Are prices provided?

No. Enter your supplier’s product coverage, packaging and price. Missing prices are never invented.

Can I reuse measurements?

Save to a named project area, then open a compatible calculator from that area.

Estimates are based on your measurements and product information. Confirm package coverage and quantities with your supplier before purchasing. Not structural or building-code advice.