The right amount.
The better can combination.
Estimate paint for one room, then compare gallons and quarts using the prices on your shelf.
Compare before buying.
Prices and measurements are examples until you enter your own. Comparisons assume both can sizes are available. No live prices or affiliate links are configured.
From wall area to cans
For a rectangular room, wall area is 2 × (length + width) × height, minus the door and window area you enter. Paint needed is wall area × coats ÷ coverage per gallon, multiplied by (1 + extra ÷ 100).
The planner compares whole gallon and quart cans that cover that target. Lowest cost sorts by price, then leftover. Least leftover sorts by excess paint, then price. Both break remaining ties with fewer cans. Each row uses the fewest quarts needed for that gallon count; extra cans that cannot improve the result are omitted.
Example: 1.2 gallons needed
At $45 per gallon and $18 per quart, one gallon plus one quart costs $63 and leaves 0.05 gallons. Two gallons cost $90 and leave 0.8 gallons. Your prices may make a different combination cheaper.
What to check at the store
Use the actual coverage and coat instructions for your chosen product. Surface texture, condition, application, and color changes can change the amount used. This tool estimates quantities; it does not select paint or determine whether primer is needed. Plan primer, ceiling paint, and trim separately. Five-gallon buckets, discounts, tax, and tint charges are outside this comparison.
Bring the supplies
- Paint color/code, product name, and finish
- Roller and cover appropriate for the surface
- Brush, tray, tape, and drop cloths
- Surface preparation supplies specified by your paint instructions
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