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Exterior Paint Calculator

Estimate how many gallons of exterior paint you need, accounting for rougher-surface coverage rates.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-25 · v1.0.0

Market
Imperial · sales tax

Exterior paint needed

7.5 gallons

Check your inputs

Coverage varies by siding texture (stucco and rough-sawn wood need more paint than smooth vinyl or fiber cement) and paint brand — check your specific product's coverage rating.

Area to cover (all coats)
2152.78 sq ft

With the figures above, the exterior paint needed comes to 7.50 gallons. Note that exterior wall area sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. The method behind this is well established, though site conditions and material batches will move it somewhat. This is calculated for United States and cites IRC 2024. Building in another market? Change the selector above so the units and code reference follow.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Exterior paint typically covers about 250-350 sq ft per gallon per coat, lower than interior drywall's ~350-400 sq ft due to siding texture and porosity

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why is exterior coverage lower than interior paint?
Exterior surfaces like stucco, brick, and wood siding are more textured and porous than smooth interior drywall, so more paint soaks in and covers less area per gallon.
Do I need a separate primer calculation?
For bare wood, masonry, or a drastic color change, yes — run this calculator again with 1 coat to estimate primer separately, since primer and topcoat are usually different products.
Does trim paint factor into this?
No — this is field/siding area only. Trim (fascia, soffits, window/door casings) typically uses a separate paint and a much smaller quantity, best estimated by its own linear footage.