How much exterior paint do I need?

Measure each wall elevation: perimeter × height, subtract windows and doors. Textured siding often needs 250–300 sq ft/gal instead of 350. Add all sections in the calculator.

How many gallons of paint for a room?

Paintable wall area = perimeter × height minus doors (~21 ft² each) and windows (~15 ft² each). Gallons = area × coats ÷ coverage (default 350 ft²/gal), rounded up.

How many coats should I plan for?

Two coats is standard for walls. One coat may suffice over similar color; new color or bare drywall often needs two. Adjust the coats field in the calculator.

Exterior Paint Calculator

Exterior paint often covers 250–300 sq ft per gallon on textured siding. Enter each wall section as a room using perimeter × height, or combine elevations. We include coats and optional primer.

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Rooms

Room 1

Perimeter (ft)

Wall height (ft)

Doors

Windows

Ceiling area (ft², optional)

Coats (Coverage)

Coverage (ft²/gal)

Price per gallon ($, optional)

1 coat at 250 ft²/gal on bare or patched walls

Adds 20% waste for overspray

Result

3 gallons

480 ft² paintable · 2 coats · 350 ft²/gal

Per room

Room 1: 480 ft² → 3 gal

480 ft² × 2 ÷ 350 = 3 gallons

350 ft²/gal coverage assumes mid-range interior latex with two coats — verify on your paint can label. Full methodology

Plan the rest of your project

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Exterior paint often covers 250–300 sq ft per gallon on textured siding. Enter each wall section as a room using perimeter × height, or combine elevations. We include coats and optional primer.

Frequently asked questions

How much exterior paint do I need?: Measure each wall elevation: perimeter × height, subtract windows and doors. Textured siding often needs 250–300 sq ft/gal instead of 350. Add all sections in the calculator.
How many gallons of paint for a room?: Paintable wall area = perimeter × height minus doors (~21 ft² each) and windows (~15 ft² each). Gallons = area × coats ÷ coverage (default 350 ft²/gal), rounded up.
How many coats should I plan for?: Two coats is standard for walls. One coat may suffice over similar color; new color or bare drywall often needs two. Adjust the coats field in the calculator.

Frequently asked questions

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