Convert between litres, gallons, millilitres, cups and more.
Converted instantly in your browser.
How do you convert litres to gallons and other volume units?
Each volume is converted to litres, then to the target unit; for example, 1 US gallon = 3.785412 L and 1 UK gallon = 4.54609 L. So 1 US gallon = 3.7854 litres = 3,785.4 millilitres = 16 US cups. US and UK gallons differ: a UK gallon is about 20% larger.
Understanding your result
US and UK (imperial) gallons differ: a UK gallon is about 20% larger. The cup, tablespoon and teaspoon here are US customary measures.
Formula and method
Each volume is converted to litres, then to the target unit. For example, 1 US gallon = 3.785412 L and 1 UK gallon = 4.54609 L.
Assumptions and limitations
The tool converts volume (capacity), not weight, so it cannot tell you the mass of an ingredient without its density. US and UK gallons differ (3.785 L vs 4.546 L) and are listed separately; the US customary units shown here are not identical to the UK imperial cup or fluid ounce, which matters when following recipes from different countries.
Worked example
1 US gallon = 3.7854 litres = 3,785.4 millilitres = 16 US cups.
Common volume conversions
| Convert | Equals |
|---|---|
| 1 US gallon | 3.78541 litres |
| 1 litre | 0.264172 US gallons |
| 1 UK gallon | 4.54609 litres |
| 1 US cup | 236.588 millilitres |
| 1 litre | 33.814 US fluid ounces |
| 1 cubic metre | 1,000 litres |
| 1 US pint | 473.176 millilitres |
| 1 US quart | 0.946353 litres |
| 1 US fluid ounce | 29.5735 millilitres |
| 1 US gallon | 0.832674 UK gallons |
How to use this tool
- Enter the volume value.
- Choose the units to convert from and to.
- Read the result and the full unit table.
Common mistakes to avoid
- Mixing US and UK gallons — they are not the same size.
About the Volume Converter
Convert a volume between metric and US units, including cooking measures like cups and tablespoons. Enter a value and see every unit at once.
Who should use this tool
Cooks converting recipe volumes, travellers comparing fuel or drink sizes between gallons and litres, and anyone working across US and UK measures. It covers cubic metres and litres alongside US and UK gallons, quarts, pints, cups, fluid ounces, tablespoons and teaspoons.
Benefits
- Keeps US and UK gallons separate so you never mix the two systems
- Covers kitchen units (cups, tablespoons) and bulk units (litres, cubic metres)
- Exact factors based on the litre and the US customary definitions
- Private, instant and available offline
Practical use cases
- Scaling a recipe written in cups into millilitres or litres
- Comparing fuel economy or tank sizes between gallons and litres
- Converting a drink or bottle size across regions
- Working out container capacity in cubic metres for shipping or storage
Explore all Unit Converters tools
Frequently asked questions
How many litres in a US gallon?
One US gallon is about 3.7854 litres.
Is a US gallon the same as a UK gallon?
No. A UK (imperial) gallon is about 4.546 litres, larger than the US gallon.
How many litres are in a US gallon?
One US gallon equals 3.78541 litres. A UK (imperial) gallon is larger at 4.54609 litres, so always check which gallon a figure refers to before converting.
How many millilitres are in a cup?
A US customary cup is 236.588 millilitres. Metric recipes often round this to 250 ml, and the UK does not use a standard cup measure, so results can differ slightly between recipe sources.