Convert Imperial Gallon to Liter
Convert imperial gallons to liters instantly. 1 imperial gallon = 4.54609 liter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Liter to Imperial Gallon converter for the reverse conversion.
Units explained
Imperial Gallon
The imperial gallon is defined as exactly 4.54609 liters.
Set by the British Weights and Measures Act of 1824 as the volume of 10 lb of water.
Used for fuel and beverages in the UK and Commonwealth.
UK, 1824.
Liter
The liter is a metric unit of volume equal to one cubic decimeter (0.001 m³). It is the everyday metric volume unit.
Introduced in France in 1795; redefined in 1964 as exactly one cubic decimeter.
The world's common unit for beverages, fuel, and household liquids.
France, 1795; CGPM 1964.
Imperial Gallon to Liter conversion formula
The relationship between imperial gallons and liters:
To convert imperial gallons to liters, multiply the value in imperial gallons by 4.54609. To reverse, multiply liters by 0.2199692483.
How to use this converter
Type a value into the calculator. The result in liters updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Liter to Imperial Gallon converter for the reverse direction.
Step-by-step: convert imperial gallons to liters
- Write down the value in imperial gallons (gal).
- Multiply that value by the factor 4.54609.
- The product is the equivalent value in liters (L).
- To reverse, multiply the liter value by 0.2199692483.
Worked examples
Example 1 — Convert 1 gal to L:
1 × 4.54609 = 4.54609 L
Example 2 — Convert 100 gal to L:
100 × 4.54609 = 454.609 L
Real-world example — Hardware-scale dimensions
A 10-imperial gallon fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between imperial gallons and liters daily when mixing metric and imperial tools.
10 gal × 4.54609 = 45.4609 L
Real-world example — Postcard and small-object dimensions
A postcard is about 5 imperial gallons wide. Converting to liters is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 gal × 4.54609 = 22.73045 L
Real-world example — Ruler-scale measurements
A 30-imperial gallon school ruler converts cleanly to liters — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 gal × 4.54609 = 136.3827 L
Imperial Gallon to Liter conversion table
Standard reference values for converting imperial gallons to liters:
| Imperial Gallon [gal] | Liter [L] |
|---|---|
| 0.01 | 0.0454609 |
| 0.1 | 0.454609 |
| 1 | 4.54609 |
| 2 | 9.09218 |
| 3 | 13.63827 |
| 4 | 18.18436 |
| 5 | 22.73045 |
| 10 | 45.4609 |
| 20 | 90.9218 |
| 30 | 136.3827 |
| 40 | 181.8436 |
| 50 | 227.3045 |
| 100 | 454.609 |
| 500 | 2273.045 |
| 1000 | 4546.09 |
Frequently asked questions
How many liters is 1 imperial gallon?
How do I convert imperial gallons to liters?
How do I convert liters back to imperial gallons?
How many liters is 100 imperial gallons?
Popular volume unit conversions
Convert Imperial Gallon to other volume units
Show all Imperial Gallon conversions
Metric / SI (15 units)
US Customary (Liquid) (15 units)
US Customary (Dry) (5 units)
Imperial (UK) (13 units)
Cubic (length-derived) (4 units)
Cooking / Culinary (5 units)
Sources & references
Conversion factor (1 gal = 4.54609 L) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.