What this converter does
This converter turns US gallons into litres and back instantly. It also handles millilitres, cubic metres, quarts, pints and imperial gallons — every pair uses an exact factor. Type a value, pick your units, and read the answer as you type.
One US gallon is defined as exactly 3.785411784 litres; the imperial gallon is 4.546 litres. Choose the right one for your region. Unit definitions follow NIST.
The units it covers
Every volume unit converts through the litre with a fixed ratio.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Litre | L | 1 | Metric liquid volume |
| Millilitre | mL | 0.001 | Small volumes |
| Cubic metre | m³ | 1000 | Bulk volume |
| US gallon | gal | 3.785412 | US fuel, liquids |
| US quart | qt | 0.946353 | US recipes |
| US pint | pt | 0.473176 | US drinks |
| Imperial gallon | imp gal | 4.54609 | UK liquids |
The formula
Each unit has a fixed value in litres, so converting goes through the litre once:
result = value × factor_from ÷ factor_toWhere:
- value = the number you typed
- factor_from = the “from” unit’s value in litres
- factor_to = the “to” unit’s value in litres
Worked example
Convert 5 US gallons to litres.
1 gal = 3.785412 L5 × 3.785412 = 18.927 LSo 5 US gallons is about 18.9 litres.
The units in this example
The US customary liquid gallon, used for fuel and beverages in the United States.
- 1 gal = 3.7854 L
- 1 gal = 4 US qt
- 1 gal = 128 fl oz
- 1 gal = 0.8327 imp gal
The metric unit of liquid volume, one cubic decimetre, used almost everywhere.
- 1 L = 0.2642 US gal
- 1 L = 1,000 mL
- 1 L = 1.0567 US qt
- 1000 L = 1 m³