How much exterior paint for a house?
Wall area ≈ 2 × wall height × (length + width) of the footprint. A 40×30 ft two-story home can need 15–25 gallons for two coats — depends on siding texture and color change.
Exterior Paint Calculator
Exterior latex covers less area than interior paint — default 250 sq ft per gallon on porous siding. Enter building footprint and average wall height for gallon estimates with Canadian coverage defaults. Use this before you order delivery so one weekend of good weather is enough product.
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Project settings
Default 10% for touch-ups
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Siding and texture
Rough cedar, stucco, and previously unpainted wood absorb more paint than smooth hardboard. Use the sq ft per gallon printed on your exterior can — often 200–300 sq ft/gallon.
Bold colour changes over dark siding usually need primer plus two topcoats — run the calculator twice or raise coat count. A light refresh over the same colour on sound paint may finish in one heavy coat plus touch-ups.
Footprint example
A 40 × 30 ft bungalow with 9 ft walls is about 2 × 9 × (40 + 30) = 1,260 sq ft of wall. At 250 sq ft/gallon and two coats you need about 10.1 gallons — buy 11 to cover waste, porches, and touch-ups. Bump waste to 15% if you have heavy texture or lots of trim returns.
Trim, soffits, and Canadian weather windows
This tool focuses on main wall area. Many DIYers buy trim paint by the quart separately — the 10% waste allowance helps cover some fascia and soffit area.
Plan exterior painting when overnight lows stay above ~10°C and rain is unlikely for 24 hours. For stain instead of paint, switch to the exterior house stain calculator.
Related guides
Frequently asked questions
How many coats of exterior paint?
Most exterior repaints need two coats over primer or a significant color change. Maintenance coats over similar color may be one. Adjust coats in settings.
Does this include trim and soffits?
This focuses on main wall area. Add waste % or run separate calculations for trim — many DIYers buy trim paint by the quart.
Related calculators
Paint Calculator · https://paint-calculator.ca/exterior-paint-calculator/