This online calculator converts volume from US liquid gallons (US gal) to UK gallons (Imperial gal, Imp gal). Factors are based on exact litre definitions: 1 US gal = 3.785411784 L; 1 Imperial gal = 4.54609 L. The ratio is fixed and traceable to SI (litre), suitable for brewing, fuel logistics, packaging, and engineering specs.
US Gallons (US gal) to UK Gallons (Imperial gal) Converter
Enter a value in US liquid gallons to convert it to UK (Imperial) gallons.
US Gallons (US gal)
Result in UK Gallons (Imperial gal)
How to Use
- Enter a number in the “US Gallons (US gal)” field.
- Set “Decimal Places” (0–10) to control rounding in the result and in the calculation line.
- Select “Convert” to compute the equivalent in UK (Imperial) gallons.
- Use “Copy Result” to copy the numeric output.
- Choose “Clear All” to reset inputs, result, and the calculation note.
- Press the “Swap” button to perform the reverse conversion.
Definitions and Unit Facts
US liquid gallon (US gal) — US customary unit of volume defined exactly as 231 cubic inches, which equals 3.785411784 litres (L). System: US customary. In Imperial terms, 1 US gal = 3.785411784 ÷ 4.54609 = 0.8326741846 Imp gal. Common in beverages, fuels, containers, and retail packaging in the United States.
UK gallon (Imperial gal, Imp gal) — Imperial unit of volume defined exactly as 4.54609 litres (L). System: Imperial. Relative to the US liquid gallon, 1 Imp gal = 4.54609 ÷ 3.785411784 = 1.2009499255 US gal. Widely used historically in the UK and in specific industries (e.g., cask ale volumes).
Conversion Formula
Imperial gal = US gal × (3.785411784 ÷ 4.54609) = US gal × 0.8326741846
US gal = Imperial gal × (4.54609 ÷ 3.785411784) = Imperial gal × 1.2009499255
Source: NIST
Conversion Table
| US gallons (US gal) | UK gallons (Imp gal) |
|---|---|
| 0.10 | 0.083267 |
| 0.25 | 0.208169 |
| 0.50 | 0.416337 |
| 0.75 | 0.624506 |
| 1.00 | 0.832674 |
| 1.50 | 1.249011 |
| 2.00 | 1.665348 |
| 3.00 | 2.498023 |
| 4.00 | 3.330697 |
| 5.00 | 4.163371 |
| 7.50 | 6.245056 |
| 10.00 | 8.326742 |
| 12.50 | 10.408427 |
| 15.00 | 12.490113 |
| 20.00 | 16.653484 |
| 25.00 | 20.816855 |
| 30.00 | 24.980226 |
| 50.00 | 41.633709 |
| 75.00 | 62.450564 |
| 100.00 | 83.267418 |
Real-World Examples
- Milk jug 1 US gal: 0.832674 Imp gal
- Water cooler bottle 5 US gal: 4.163371 Imp gal
- US half-barrel beer keg 15.5 US gal: 12.906450 Imp gal
- US quarter-barrel keg 7.75 US gal: 6.453225 Imp gal
- US sixth-barrel keg 5.16 US gal: 4.296599 Imp gal
- US oil barrel 42 US gal: 34.972316 Imp gal
- 55-gallon drum 55 US gal: 45.797080 Imp gal
- Homebrew carboy 6 US gal: 4.996045 Imp gal
- Cooler jug 10 US gal: 8.326742 Imp gal
- Jerrycan 5 US gal: 4.163371 Imp gal
What do you use this calculator for? If you want additional volume converters or industry-specific tools, please tell us in the comments and we will prioritize them.
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