Paint Calculator

Formula

gallonsPerCoat = area / coverageRatetotalGallons = ⌈gallonsPerCoat × coats × (1 + waste/100)⌉

Parameters

Coats

Number of coats. Most projects need 2.

Coverage Rate

Sq ft per gallon. Standard latex: ~350 sq ft/gal.

Waste %

Extra for rollers, drips, touch-ups.

Results

Gallons Needed

Total gallons including waste.

Example

gallonsPerCoat = 480 / 350 = 1.37totalGallons = ⌈1.37 × 2 × 1.10⌉ = 4 gal

Common Use Cases

• Interior walls and ceilings
• Exterior siding and trim
• Accent walls and feature rooms
• Commercial space repaints

Notes

• Dark-to-light changes may need primer + 2 finish coats.
• Textured surfaces use more paint — lower the coverage rate.
• Typical coverage rates: standard interior latex ≈ 350 sq ft/gal, exterior ≈ 250–300 sq ft/gal, primer ≈ 200–300 sq ft/gal, stain ≈ 150–250 sq ft/gal.
• Sheen affects coverage slightly: flat and matte cover ~5% more area than semi-gloss and gloss per gallon.

Frequently Asked Questions