Paint Calculator — Litres & Coverage

Calculate how much paint you need based on wall area, number of coats and paint coverage rate.

Last updated: April 2026 · Source: GOV.UK — Building Regulations Approved Document F

Paint Needed

5.8L

2.5L Tins

3

5L Tins

2

Wall Area

34.8 m²

Disclaimer

This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.

How It Works

Paint coverage depends on the product type and surface texture. Emulsion paint for walls typically covers 10–12 m² per litre on smooth plaster. Gloss and satin for woodwork cover 12–16 m² per litre. Textured, bare or porous surfaces may require 20–30% more paint due to increased absorption on the first coat.

This calculator measures each wall (height × width), subtracts doors and windows, then divides the total area by the coverage rate. Two coats are standard for a colour change; a single coat may suffice for maintenance. The calculator adjusts for your chosen number of coats.

Enter room dimensions, number of doors and windows, and choose the paint type and number of coats. The calculator shows total litres needed and suggests tin sizes (most UK paints come in 2.5 L and 5 L tins). Buying the next size up is usually more economical than buying an extra small tin.

Example: Room 4 m × 3.5 m, 2.4 m ceiling, 1 door, 1 window, 2 coats emulsion

  1. Wall area: 2 × (4 + 3.5) × 2.4 = 36 m²
  2. Less door (1.8 m²) and window (1.5 m²): 32.7 m²
  3. Two coats: 32.7 × 2 = 65.4 m²
  4. Litres needed: 65.4 ÷ 11 = 5.9 L — buy 2 × 2.5 L or 1 × 5 L + 1 × 2.5 L

Source: GOV.UK — Building Regulations Approved Document F

Frequently Asked Questions

What does the Paint Calculator — Litres & Coverage do?
Calculate how much paint you need based on wall area, number of coats and paint coverage rate. All calculations are performed in your browser using official UK rates and thresholds.
Does this include waste allowance?
Yes. Most building material calculations include a standard 10% waste allowance. You can adjust this figure depending on the complexity of your project and cutting requirements.
Are prices accurate?
Material prices are indicative estimates based on average UK prices. Actual costs vary by region, supplier, brand and current market conditions. Always get quotes from local suppliers.