Calculators · Inside the building

Paint calculator

Gallons for a room, openings deducted.

How it is worked out

2 × (L + W) × height − openings = wall sq ft × coats ÷ coverage = gallons

What it assumes

A door is counted at 21 sq ft (a 3'0" × 7'0" opening), a window at 15 sq ft. Rough allowances, and generous ones.
350 sq ft per gallon is a common spread rate on primed drywall. Bare or dark walls drink more.
Ceilings are not in this number — add them as their own area.

This is the same calculator that is in your Hub

Nothing on this page is a demo of the real thing — it runs the identical code. What a TradeForge account adds is everywhere the number then goes: saved against the job it belongs to, dropped straight onto a quote, and priced at a rate built from your own overhead instead of a guess.

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