Gallons to Liters Converter

The tool multiplies by 3.785411784, the exact size of the US liquid gallon in liters. Containers sold by the gallon convert like this:

A tank rating is its gross volume. Gravel, decorations and the gap at the top all take some of it, so the water you actually treat is less than the converted figure.

Prices go the opposite way from volumes. A volume in gallons is multiplied by about 3.78541, but a price per gallon is divided by 3.78541, because each liter is a smaller share of the gallon.

• $3.29 per gallon ÷ 3.78541 = $0.86913 per liter
• $4.10 per gallon ÷ 3.78541 = $1.0831 per liter

Comparing fuel or milk prices across countries is where people slip. If you multiply the price instead, $3.29 becomes $12.45 a liter and the comparison is useless.

A UK (imperial) gallon is about 4.5461 L, against 3.7854 L for the US gallon this tool uses. If the gallons in front of you are imperial, the tool's answer comes out 16.73% too low. Ten imperial gallons are about 45.4609 L; the tool gives 37.8541 L for ten US gallons.

Clues that you are looking at imperial gallons: a UK or older Commonwealth source, fuel economy quoted as UK mpg, or a container that seems oddly large for its label.

Multiplying by 4 is 5.67% high: 10 gal × 4 = 40 L against 37.8541. Multiplying by 3.8 is only 0.39% high (38 L), and you get it by doing ×4 and then taking off 5%.

Every other kitchen unit in the tool's list is a US customary measure built from the same gallon, so the splits are exact: 1 gallon shows as 4 quarts, 8 pints, 16 cups or 128 fluid ounces when you change the To menu. That is handy for dividing a gallon of punch or stock into servings without going through liters at all.