Complete Guide: How to Calculate Exterior Paint Needed
An exterior paint calculator converts your house's footprint and wall height into the total exterior wall surface area, then divides by your paint's coverage rate to estimate gallons needed. This free tool accounts for multiple coats, since most exterior jobs need at least two for even coverage and durability.
💡 Quick Summary
Wall area = house perimeter × average wall height. Multiply by your number of coats, then divide by the paint's coverage rate (typically 300-400 sq ft per gallon) to get total gallons.
Typical Paint Coverage Rates
- 350 sq ft/gallon: A commonly used default for smooth exterior surfaces like siding.
- 250-300 sq ft/gallon: Typical for rougher textures like stucco or brick, which absorb more paint.
- Always check your specific paint can, since coverage varies by brand and formulation.
Step-by-Step Instructions
- Enter your house footprint length and width, and average wall height.
- Select the number of coats (2 is standard for most exterior projects).
- Adjust the coverage rate to match your specific paint product if known.
- Click ⚡ Calculate Paint Needed.
- Review your total gallons needed, then use 📋 Copy Summary to save your results.
Tip: This calculator doesn't subtract doors and windows, which naturally builds in a small buffer for trim work, drips, and touch-ups.