Volume Converter
Turn any volume into a different unit — metric, US customary, or UK imperial — using exact conversion factors.
Exact factors
Every conversion uses official definitions, so a US gallon is exactly 3.785411784 litres — never a rounded approximation.
US vs UK gallon
A US gallon (~3.785 L) is smaller than a UK gallon (~4.546 L). Pick the right one — they are not interchangeable.
What is a volume converter?
One value, any unit
A volume converter changes a measurement from one unit into another — litres to gallons, millilitres to cups, fluid ounces to centilitres, and back. It works by translating every unit through a single shared base, the litre, so any pair of units can be converted with one consistent rule. This tool covers twelve common units across the metric, US customary, and UK imperial systems, making it useful for cooking, brewing, fuel, chemistry, schoolwork, and anywhere measurements in different systems need to meet.
Each unit has an exact size in litres. To convert, the value is first turned into litres, then into the target unit.
Result = value × (litres per from-unit) ÷ (litres per to-unit)Because the conversion factors are exact definitions — US gallon = 3.785411784 L, UK gallon = 4.54609 L, US cup = 0.2365882365 L, and US fluid ounce = 0.0295735295625 L — the result is mathematically exact, limited only by how many decimal places are displayed. The same single rule handles every direction, so converting litres back to gallons just swaps which factor divides.
Suppose you want to convert 1 US gallon into litres.
Find the base size
A US gallon is, by definition, 3.785411784 litres.Divide by the target factor
A litre is 1 litre, so 3.785411784 ÷ 1 = 3.785412.Read the result
1 US gallon converts to about 3.785412 litres.
The converted figure is exact to the precision shown. Metric units (ml, cl, l, m³) scale in powers of ten, so moving the decimal point is often enough between them, while customary conversions rely on the fixed factors above. The biggest trap is the gallon: a US gallon is about 3.785 L, but a UK (imperial) gallon is about 4.546 L — roughly 20% larger. The same applies further down the chain, since US pints, quarts, and fluid ounces are defined from the US gallon. Always confirm whether a recipe, fuel figure, or spec means US or UK measure before you convert, or you will be off by a fifth.
The arithmetic is exact; the only limit is display precision.
Rounding and unit choice
Results are rounded to six decimal places, so converting between units that differ enormously in size — millilitres to cubic metres, for example — can lose the last digits. This converter handles fluid volume only; the cups, tablespoons, and teaspoons here are US customary, which differ from metric or UK kitchen measures. For trade, dispensing, or precision work, always confirm against the governing standard for your field.