Exterior Paint Calculator
Pick your siding material and we'll adjust coverage automatically — vinyl, stucco, and brick don't drink up paint the same way, and getting this wrong means an extra trip to the store mid-job.
Fill in your siding details and click Calculate to see your exterior paint estimate.
How to Calculate How Much Exterior Paint You Need
Exterior paint coverage depends far more on siding material than most DIYers expect. A gallon that covers 400 sq ft of smooth vinyl might only stretch across 250 sq ft of stucco — the texture and porosity of the surface change how much paint actually gets absorbed versus sitting on top where it belongs.
The Basic Formula
Measure your total exterior wall area, multiply by the number of coats, then divide by the coverage rate for your specific siding material. Rough or porous materials pull coverage down; smooth, sealed materials stretch a gallon further.
Why Siding Material Matters
Vinyl and fiber cement siding are relatively smooth and factory-primed, so they accept paint evenly and need less of it. Wood siding sits in the middle. Stucco and masonry are the most porous and textured surfaces on this list, and they can use noticeably more paint per square foot than a smooth wall — sometimes 30 to 40% more.
When You Need to Prime First
Bare siding, chalky or weathered surfaces, and anything peeling, damaged, or water-stained should be primed before topcoat paint goes on. Skipping primer on these surfaces usually means poor adhesion, uneven color, and a repaint sooner than you'd like. Use our Primer Calculator to estimate that step separately — it accounts for surface type and primer type on its own.
One Coat or Two?
Two coats is the standard recommendation for most exterior repaints, especially with a color change or after several years of weathering. One coat can be enough for a same-color touch-up on a surface that's already in good condition.
Planning the Full Exterior Job
If part of your project also includes trim, fences, or interior walls, check our Paint Calculator and Fence Calculator to estimate those separately — exterior siding, trim, and fencing each have different coverage needs.