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Free paint cost calculator
Gallons and material cost for any paint job. Free, no signup.
Calculate now — free
Enter your numbers and watch the results update live.
Quoting a paint job starts with the materials: how many gallons the walls will drink, and what they cost. Enter the wall area, coats, the paint's coverage rating, and the price per gallon — the calculator returns gallons needed and the material cost to build into your quote.
The formula, in plain English
Gallons = wall area × coats ÷ coverage per gallon. Cost = gallons × price per gallon. A 400 sq ft room, two coats, paint rated at 350 sq ft per gallon: 400 × 2 ÷ 350 = 2.3 gallons.
Worked example
Two rooms totaling 400 sq ft of wall, two coats, coverage 350 sq ft/gal, paint at $45/gallon: gallons = 2.3, material cost = 2.2857 × 45 = $102.86. Add labor, primer, and supplies on top when you build the quote.
Tips
- Measure walls, then subtract the big openings. Rough wall area minus large windows and doors gets you close enough for quoting — precision comes at measuring time.
- Dark-to-light needs an extra coat. Coverage ratings assume similar colors; dramatic color changes drink more paint.
- Round up, not down. Running out mid-wall costs more in time and mismatch than a leftover half-gallon ever will.
Also free
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Frequently asked questions
What does 'coverage per gallon' mean?
It is the manufacturer's rating of how many square feet one gallon covers in one coat — usually 250–400 sq ft. Find it on the paint can label.
Does this include primer?
No — this is finish paint only. Primer is a separate line item; add a coat's worth of primer cost when the surface needs it.
How do I turn this into a customer quote?
Add your labor, primer, and supplies to the material cost, then build the quote in our free estimate maker — it keeps estimates and invoices in one numbering flow.
Is this calculator really free?
Yes. Unlimited calculations, no signup, no watermark, no catch — like all of Billia's free tools.
Turn the number into an invoice
Ran the numbers? Bill it with Billia's free invoice generator — no signup, no watermark.