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How to Calculate Paint Size

What is Paint Size?

Paint coverage and quantity calculations help determine exactly how many tins to buy for a project. Buying too little means colour-matching issues; buying too much wastes money. Always round up to the next tin size.

Formula

Area to paint = total wall/ceiling area minus doors and windows

Step-by-Step Guide

  1. 1Area to paint = total wall/ceiling area minus doors and windows
  2. 2Litres needed = Area ÷ coverage rate × number of coats
  3. 3Coverage rates: emulsion 10–14m²/L, gloss 13–17m²/L, masonry 5–8m²/L

Worked Examples

Input
40m² walls, 2 coats, 12m²/L emulsion
Result
6.7L → buy 2×4L tins
40/12×2 = 6.67L — standard 4L tins cover efficiently

Frequently Asked Questions

What is Paint Size?

Paint coverage and quantity calculations help determine exactly how many tins to buy for a project. Buying too little means colour-matching issues; buying too much wastes money

How accurate is the Paint Size calculator?

The calculator uses the standard published formula for paint size. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Paint Size calculator use?

This calculator works with inches, square metres. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Paint Size calculator use?

The core formula is: Area to paint = total wall/ceiling area minus doors and windows. Each step in the calculation is shown so you can verify the result manually.

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