PAINT CALCULATOR

How Much Paint Do I Need?

Get an accurate estimate for primer and paint based on your room dimensions and surface texture.

Room Details

Wall Area (sq ft)

Ceiling Area (sq ft)

Doors

Windows

Surface Texture

Coverage: 375 sq ft/gal paint, 350 sq ft/gal primer

Color Change (Dark to Light)

Adds an extra coat of paint for better coverage

Primer Needed

Required for new drywall, repairs, or porous surfaces

Paint Cost per Gallon (optional)

Enter your paint price to see estimated total cost

Your Paint Estimate

Primer

1.5

gal

Paint

2.5

gal (2x)

Total

4.0

gal

Est. Cost

—

enter price

Shopping List

Buy 2 gallons of primer

Buy 3 gallons of paint

I understand this is an estimate

Estimate only. Test a small area first. Actual coverage varies by paint brand, application method, surface condition, and technique.

Show the Math

Net Coverage Area: 400 + 0 - (1 doors × 20 + 2 windows × 17.5) = 345 sq ft

Primer: (345 ÷ 350) × 1.1 waste factor = 1.5 gal

Paint: (345 ÷ 375) × 2 coats × 1.1 waste factor = 2.5 gal

Why add 10% waste? Paint is lost to roller nap, brush absorption, drips, touch-ups, and uneven surfaces. Planning for 10% extra prevents mid-project store runs.

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