Exterior Paint Calculator for Facades

This page opens the paint calculator preset for exterior walls: direct area input with coverage lowered to 8 m² per liter, because facade surfaces — render, roughcast, masonry, fiber cement — are more porous and textured than interior plaster and drink noticeably more paint. Measure each facade as width × height, add them up, and subtract windows and doors using the openings fields.

A worked example: 100 m² of facade at two coats and 8 m²/L needs 25 liters — two 10 L cans plus a 5 L can. Two coats is the norm outdoors: the first partly disappears into the substrate, the second builds the weatherproof film. On bare or patched render, add a primer coat first; primer is calculated separately and often halves the topcoat's absorption.

Real coverage outdoors swings widely — smooth painted render can reach 10 m²/L while coarse roughcast can drop to 4–6 m²/L, so check the range printed on your specific paint and adjust the coverage field. Buy in large cans from the same batch number where possible: facades are unforgiving of tint differences, and a 10–15% reserve saves a second trip and a visible patch. Everything is calculated locally in your browser.