Understanding your result
The headline is the converted amount in the unit you asked for, and the sub-line gives it in US gallons and litres, or the cans to buy if you chose rounding. The three figures show the amount in US gallons, litres and quarts, the three units paint is usually bought in.
The table lists the same amount in every unit the converter knows, so one entry answers every follow-up question, and if rounding is on, the last row gives the cans with their total in gallons and litres. The notes say how much extra the cans hold and point out the UK gallon, which is the conversion people most often get wrong.
Conversions are the glue between calculators and data sheets. The can size optimizer finds the cheapest combination of cans once you know the quantity; the paint coverage calculator converts coverage figures between square feet per gallon and square metres per litre; the mixing ratio calculator works in fluid ounces and millilitres for a custom colour; and the sample pot calculator starts from 8 oz pots.
How we calculate this
Every unit is converted through US gallons with exact definitions: the US gallon is defined as 231 cubic inches, which is 3.785411784 litres, and the quart, pint and fluid ounce are fixed fractions of it. The UK gallon is defined as 4.54609 litres. Nothing is rounded until the display, and the display shows three decimals for gallons and litres, two for quarts and pints, one for fluid ounces and none for millilitres.
The rounding to cans uses the same rule as every calculator on the site: in US sizes, quarts up to a gallon, then gallons, then a 5-gallon pail once the remainder passes four gallons; in metric sizes, 10 L, 5 L, 2.5 L and 1 L. The can sizes and conversions reference lists the factors and the containers, and the can sizes guide explains the buying maths.
The assumptions behind the numbers
| Assumption | Value | Where it comes from |
|---|---|---|
| US gallon | 3.785411784 L (231 cu in) | US customary definition, exact |
| US quart, pint, fluid ounce | 1/4, 1/8, 1/128 gallon | US customary definitions |
| UK gallon | 4.54609 L | UK Weights and Measures Act definition, exact |
| US can sizes | quart, gallon, 5-gallon pail | Standard US retail sizes |
| Metric can sizes | 1, 2.5, 5, 10 L | Common European and Canadian retail sizes |
| Sample pot | 8 fl oz (237 mL) | Typical US sample size |
Assumptions last reviewed October 8, 2026.
The converter does not convert by weight; paint density varies by product, and the paint weight calculator handles that with typical densities. It does not know the can sizes your store stocks; some sell 3.78 L “gallons” in Canada and 0.9 L “quarts”, which are the metric versions of the US sizes.
Two worked examples
A European data sheet’s 2.5 litres
A colour sold in 2.5 L cans abroad, converted to quarts and rounded to US cans.
- In gallons: 2.5 × 0.264172 = 0.66 gallons
- In quarts: 0.66 ÷ 0.25 = 2.64 quarts
- US cans: 3 quarts, holding 0.36 quarts (0.34 L) more than needed
The other units in the table: 5.28 pints, 84.5 fl oz, 2,500 mL, 0.55 UK gallons.
12 litres from a metric estimate, bought in the US
A metric estimate of 12 L converted to gallons and rounded to US cans.
- In gallons: 12 × 0.264172 = 3.17 gallons
- US cans: 3 gallons + 1 quart (3.25 gallons, 12.3 L)
And the trap: 1 UK gallon is 1.201 US gallons, 4.546 L or 4.8 US quarts. An old British coverage figure “per gallon” is a fifth more generous than a US one.
Where to find your inputs
Amount and unit. From the can, the data sheet, the recipe or another calculator. Check whether a “gallon” is US or UK; the country of the document usually says.
Target unit. What the store or the recipe uses.
Rounding. US cans if you are buying in the US, metric cans elsewhere, none for a recipe.
Common mistakes
- Treating a UK gallon as a US gallon. It is 20% larger.
- Assuming 4 litres is a gallon. It is 3.785; the difference is a cup on every gallon.
- Buying the converted figure exactly. Round up to cans that exist.
- Converting coverage with a volume factor alone. Coverage needs the area factor too; the coverage calculator does both.
- Confusing fluid ounces with weight ounces. Paint recipes use fluid ounces.
- Rounding before converting. Convert first, round to cans last.
Questions people ask
- How many litres are in a gallon of paint?
- A US gallon is exactly 3.785411784 litres, so 3.785 L. A UK (imperial) gallon is 4.546 L. US paint is sold in US gallons; a "gallon" on a British or Canadian can from before metrication was the larger UK gallon.
- How many quarts in a gallon?
- Four US quarts make a US gallon. A quart is 32 US fluid ounces, two pints, or 946 mL. A 5-gallon pail is 20 quarts or 18.9 litres.
- How many ounces is a sample pot?
- Most US sample pots are 8 fl oz, a quarter of a quart, or 237 mL. Some brands sell 16 oz samples. The sample pot calculator works out how many patches a pot paints.
- What is 2.5 litres in quarts?
- 2.64 US quarts, which rounds up to three quarts. A 2.5 L can is a common European size and holds about two-thirds of a US gallon.
- Why round to cans?
- Because a converted figure like 3.17 gallons cannot be bought. Rounding up to US cans gives three gallons and a quart; to metric cans, a 10 L and a 2.5 L. The converter shows how much extra the cans hold.
- Are paint gallons different from other gallons?
- No. A US liquid gallon is the same for paint, fuel and milk. The only trap is the UK gallon, which is 20% larger, and dry gallons, which paint never uses.