US gallon (gal (US))
1 US gallon = 3.78541178 litres
What is US gallon?
A US gallon is a volume unit equal to 128 US fluid ounces, or approximately 3.785 litres. It is the standard unit for fuel, milk, and other liquid products in the United States.
Notes: USCS unit
Real-world uses
US gallons are used for fuel pricing and vehicle fuel economy (miles per gallon) in the United States. Milk, water, and paint are commonly sold in gallon containers. Pool volumes and water heater capacities are specified in gallons.
History
The US gallon is based on the English wine gallon of 231 cubic inches, which was defined by Queen Anne in 1707. When Britain adopted the Imperial gallon in 1824 (based on water weight), the US retained the older wine gallon standard.
Common mistakes
Confusing US gallons with Imperial gallons: a US gallon is about 3.785 litres while an Imperial gallon is about 4.546 litres—roughly 20% larger. This causes major confusion when comparing fuel economy between US and UK figures.
When is this conversion used?
Converting between US gallon and litre is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. Fuel economy, beverage volumes, and liquid measurements frequently require converting between litres and US gallons, especially for automotive and cooking contexts across different markets.
How to convert US gallon to litre
To convert US gallon to litre, multiply the value by 3.78541178.
Conversion formula (from base unit)
x * 3.785411784
Measurement standards
The cubic metre is the SI derived unit of volume. The litre, equal to exactly one cubic decimetre (0.001 m³), is accepted by the BIPM for use alongside SI units. Both the lowercase "l" and uppercase "L" are approved symbols for the litre.
Did you know?
An Olympic swimming pool holds 2,500 cubic metres of water — about 2.5 million litres. The Amazon River discharges roughly 209,000 cubic metres per second, enough to fill 84 Olympic pools every single second.
| US gallons | litres |
|---|---|
| 0.1 | 0.37854118 |
| 0.5 | 1.89270589 |
| 1 | 3.78541178 |
| 2 | 7.57082357 |
| 5 | 18.92705892 |
| 10 | 37.85411784 |
| 25 | 94.6352946 |
| 50 | 189.2705892 |
| 100 | 378.5411784 |
| 250 | 946.352946 |
| 500 | 1,892.705892 |
| 1,000 | 3,785.411784 |
Common values
| US gallons | litres | |
|---|---|---|
| A teaspoon | 0.00132086 US gallons | 0.005 litres |
| A cup of coffee | 0.06604301 US gallons | 0.25 litres |
| A water bottle | 0.13208603 US gallons | 0.5 litres |
| A bathtub | 79.25161571 US gallons | 300 litres |
| A swimming pool (Olympic) | 660,430.13089537 US gallons | 2,500,000 litres |
Full US gallon conversion table
| Unit | Value | Factor |
|---|---|---|
| litre | 1 gal (US) = 3.78541178 L | × 3.78541178 |
| millilitre | 1 gal (US) = 3,785.411784 mL | × 3,785.411784 |
| cubic metre | 1 gal (US) = 0.00378541 m³ | × 0.00378541 |
| Imperial gallon | 1 gal (US) = 0.83267418 gal (Imp) | × 0.83267418 |
| US fluid ounce | 1 gal (US) = 128 fl oz (US) | × 128 |
| Imperial fluid ounce | 1 gal (US) = 133.22786954 fl oz (Imp) | × 133.22786954 |
| teaspoon (metric) | 1 gal (US) = 757.0823568 tsp | × 757.0823568 |
| tablespoon (metric) | 1 gal (US) = 252.3607856 Tbsp | × 252.3607856 |
| cubic centimetre | 1 gal (US) = 3,785.411784 cm³ | × 3,785.411784 |