Paint Cost Calculator
Enter the gallons of paint needed, or the area, coats and coverage, and the price of each can size. The calculator finds the cheapest combination of cans that holds at least that much.
Paint Needed
6.6 gal
5-Gallon Buckets
1
1-Gallon Cans
2
Quarts
0
Total Cost
$260.00
Paint Bought
7 gal
Left Over
0.4 gal
How it works
Paint is sold in fixed sizes: quarts (a quarter of a gallon), gallons and 5-gallon buckets. The price per gallon usually falls as the container gets bigger, but a bigger container also means more paint left over. The cheapest way to buy a given amount is therefore not always the obvious one.
The calculator first rounds the paint needed up to whole quarts, the smallest size sold. It then searches every combination of the three sizes that holds at least that much and reports the one with the lowest total price. When two combinations cost the same, it shows the one with less paint left over, then the one with fewer containers.
If you know the area instead of the gallons, the paint needed is the area times the number of coats, divided by the coverage of one gallon, the same basis as the Paint Calculator.
Formula
gallons needed = area × coats ÷ coverage per gallon (area mode) quarts needed = gallons needed × 4, rounded up cost = 5-gal buckets × 5-gal price + gallons × gallon price + quarts × quart price choose the bucket, gallon and quart counts holding ≥ quarts needed with the lowest cost left over = paint bought − gallons needed
Example
A job needs 6.6 gallons, which rounds up to 27 quarts. With illustrative prices of $180 for a 5-gallon bucket, $40 a gallon and $16 a quart, one bucket plus one gallon plus three quarts holds exactly 27 quarts but costs $268.
One bucket plus two gallons holds 7 gallons and costs $260, so it is the cheapest mix: $260 for 7 gallons, with 0.4 gallon left over.
Assumptions and limitations
- Prices are what you enter. The defaults are illustrative only and are not current retail prices.
- Sales tax, discounts for buying several cans and delivery are not included.
- Only three container sizes are considered: quart (¼ gal), gallon and 5-gallon bucket. Pints, sample pots and 2-gallon containers are ignored.
- Coverage in area mode is a typical figure; the spread rate printed on the product's technical data sheet varies with the paint and with surface texture and porosity.
- Prices are rounded to the nearest cent before comparing combinations.
Frequently asked questions
Why is a 5-gallon bucket not always cheaper?
A bucket's lower price per gallon only pays off if the job uses enough of it. For a job that needs 3 gallons, three gallon cans cost less than one bucket whenever three times the gallon price is below the bucket price, even if the bucket is cheaper per gallon. The calculator compares total cost, not price per gallon.
How many quarts are in a gallon?
Four. A US gallon is 231 cubic inches and a US liquid quart is a quarter of that, so four quart cans hold the same paint as one gallon can (NIST Handbook 44, 2026 edition, Appendix C).
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