How much paint do I need for trim?

Trim is measured as length × face width; include doors and windows, then round up to quarts.

Trim paint estimates are different from walls because you’re usually painting narrow surfaces: baseboards, door/window casings, and sometimes doors.

The fastest way is to measure total linear feet, convert to square footage using an average face width, then apply coats and a small buffer.

Step-by-step: trim paint estimate

Measure baseboards as total linear feet around each room (minus large openings if you want).
Add door and window casings (linear feet) if you’re painting them too.
Convert linear feet to area: linear feet × average face width (in feet).
Choose coats (often 2 for color changes or when using a primer + top coat).
Add 5–15% buffer for brush waste and touch-ups, then round up to whole quarts/gallons.

Trim paint often goes further than wall paint, but brush work increases waste—keep a buffer.
If you’re painting doors, estimate them separately (door area × coats).
Gloss and semi-gloss show imperfections; prep can take longer than painting.
Buy enough from the same product line and sheen to avoid mismatched touch-ups.

Want the fast estimate?

Use our paint calculator and share a link that keeps your inputs.