Convert Imperial Gallons to Liters
1 imperial gallon (gal (imp)) equals 4.54609 liters (L).
1 gal (imp) = 4.54609 L
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk imperial gallon to liter converter to paste a column from Excel.
How to Convert Imperial Gallon to Liter
- 1 gal (imp) = 4.54609 L
- 1 L = 0.2199692483 gal (imp)
- Example: convert 15 gal (imp) to L: 15 gal (imp) = 15 × 4.54609 L = 68.19135 L
Formula
L = gal (imp) × 4.54609
Derivation from SI units:
- 1 imp gal = 4.54609 L = 0.00454609 m³ (exact, by definition)
- 1 L = 1 dm³ = (0.1 m)³ = 10⁻³ m³
- 1 gal (imp) = 0.00454609 m³ ÷ 0.001 m³ per L = 4.54609 L
Both units are defined exactly, so the factor is exact. Imperial Gallon definition: imperial gallon; Liter definition: liter.
Worked examples
- 1 gal (imp) is exactly 4.54609 L.
1 gal (imp) × 4.54609 = 4.54609 L - A 10 gal (imp) water butt holds 45.4609 L.
10 gal (imp) × 4.54609 = 45.4609 L
Imperial Gallon to Liter conversion table
| Imperial Gallons (gal (imp)) | Liters (L) |
|---|---|
| 0.25 gal (imp) | 1.1365225 L |
| 0.5 gal (imp) | 2.273045 L |
| 1 gal (imp) | 4.54609 L |
| 2 gal (imp) | 9.09218 L |
| 5 gal (imp) | 22.73045 L |
| 10 gal (imp) | 45.4609 L |
| 15 gal (imp) | 68.19135 L |
| 20 gal (imp) | 90.9218 L |
| 25 gal (imp) | 113.65225 L |
| 40 gal (imp) | 181.8436 L |
| 50 gal (imp) | 227.3045 L |
| 100 gal (imp) | 454.609 L |
| 1000 gal (imp) | 4546.09 L |
Where it's used
Older UK and Commonwealth specifications in imperial gallons are converted to litres for modern metric use.
Imperial Gallon to other volume units
| Conversion | 1 gal (imp) equals |
|---|---|
| imperial gallon to cubic meter | 0.00454609 m³ |
| imperial gallon to liter | 4.54609 L |
| imperial gallon to milliliter | 4546.09 mL |
| imperial gallon to cubic centimeter | 4546.09 cm³ |
| imperial gallon to cubic foot | 0.1605436532 ft³ |
| imperial gallon to cubic inch | 277.4194328 in³ |
| imperial gallon to US gallon | 1.200949926 gal (US) |
Frequently asked questions
Is a UK gallon bigger than a US gallon?
Yes, by about 20 %: 1 imperial gallon = 1.200949926 gal (US).
How many liters are in 1 imperial gallon?
1 gal (imp) = 4.54609 L.
How do I convert imperial gallons to liters?
Multiply the value in gal (imp) by 4.54609. For example, 15 gal (imp) × 4.54609 = 68.19135 L.
Is the gal (imp) to L conversion exact?
Yes. Both units are defined exactly, and 1 gal (imp) is exactly 4.54609 L.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "gallon [Canadian and U.K. (Imperial)]".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 8, non-SI units accepted for use with the SI.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Imperial Gallons to Liters. Retrieved October 17, 2026, from https://scientificconverters.com/volume/imperial-gallons-to-liters/
IEEE
Scientific Converters, "Convert Imperial Gallons to Liters," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/volume/imperial-gallons-to-liters/