Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Roofing & Exterior
Exterior Paint Calculator — Gallons by Square Feet
Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
Gallons needed for exterior paint from surface area and coverage rate. Planning estimates only — verify measurements and local codes on site.
Inputs
10020000
14
200500
025
Smart analysis
Recommendations
Tailored to your live inputs and result—guidance only, not professional advice.
- Round up
Buy a little extra for real-world waste
Measurements are ideal—paint, flooring, and food projects usually need a small overage for cuts, mistakes, and touch-ups.
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Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Surface area (sq ft)
The “Surface area (sq ft)” value used in this tool’s formula. Adjust it to see results update live.
Coats
The “Coats” value used in this tool’s formula. Adjust it to see results update live.
Coverage (sq ft/gal)
The “Coverage (sq ft/gal)” value used in this tool’s formula. Adjust it to see results update live.
Waste (%)
The “Waste (%)” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
Gallons needed for exterior paint from surface area and coverage rate. Planning estimates only — verify measurements and local codes on site. Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon. Example: 2,000 sq ft, 2 coats, 350 sq ft/gal, 10% waste → ~12.6 gallons.
Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
Example: 2,000 sq ft, 2 coats, 350 sq ft/gal, 10% waste → ~12.6 gallons.
When to use this Exterior Paint Coverage
Common use cases
- Gallons needed for exterior paint from surface area and coverage rate.
- Sanity-check with this case: 2,000 sq ft, 2 coats, 350 sq ft/gal, 10% waste → ~12.6 gallons.
- The relationship is: Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
Localized examples
- Roofing & Exterior: the example on this page uses the same formula as the widget.
What you get
- Fields: Surface area (sq ft), Coats, Coverage (sq ft/gal), Waste (%)
- Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
- Example on the page: 2,000 sq ft, 2 coats, 350 sq ft/gal, 10% waste → ~12.6 gallons.
How to Calculate Exterior Paint Coverage Step-by-Step
- 1Enter Surface area (sq ft), Coats, Coverage (sq ft/gal), then the remaining fields. Use the values you have, not a catalog average, unless that is all you know.
- 2Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
- 3Worked case: 2,000 sq ft, 2 coats, 350 sq ft/gal, 10% waste → ~12.6 gallons.
- 4Buy materials after you walk the job. This is a first-pass quantity, not a purchase order.
Governing formula
Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
2,000 sq ft, 2 coats, 350 sq ft/gal, 10% waste → ~12.6 gallons.
Example: set Surface area (sq ft) = 2,000, Coats = 2, Coverage (sq ft/gal) = 350, then read the result.
Variable definitions
- surfaceSqFt
Surface area (sq ft)
The “Surface area (sq ft)” field. Default 2000; typical range 100–20000.
- coats
Coats
The “Coats” field. Default 2; typical range 1–4.
- coveragePerGal
Coverage (sq ft/gal)
The “Coverage (sq ft/gal)” field. Default 350; typical range 200–500.
- wastePercent
Waste (%)
The “Waste (%)” field. Default 10; typical range 0–25.
- The takeoff (Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.) ignores waste, code, and what you find when you open the wall. Measure twice on site.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Gallons = (sq ft × coats × (1 + waste%)) ÷ coverage per gallon.
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Community
Reviews & Ratings
See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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