US Gallons to UK Gallons (gal to imp gal) Converter
1 US gallon (gal) = 0.832674 UK gallons (imp gal). To convert US gallons to UK gallons, multiply by 0.832674: 15 gal × 0.832674 = 12.4901 imp gal. Also searched as US gallon to imperial gallon, US vs UK gallon.
Quick facts
- 1 gal = 0.832674 imp gal
- 1 imp gal = 1.20095 gal
- Formula: imp gal = gal × 0.832674
- Quick estimate: multiply by about 0.83
How to convert US gallons to UK gallons
- Start with your measurement in US gallons.
- Multiply it by 0.832674 (the number of UK gallons in one US gallon).
- Round the answer to a sensible number of decimal places.
Worked example (a car fuel tank): 15 gal × 0.832674 = 12.4901 imp gal.
To convert UK gallons back to US gallons, multiply by 1.20095, or divide by 0.832674.
Source: NIST Handbook 44, Appendix C, and NIST SP 811 (US customary volume units).
US Gallons to UK Gallons conversion table
| US Gallons [gal] | UK Gallons [imp gal] |
|---|---|
| 0.01 gal | 0.0083267418 imp gal |
| 0.1 gal | 0.0832674185 imp gal |
| 1 gal | 0.8326741846 imp gal |
| 2 gal | 1.6653483693 imp gal |
| 3 gal | 2.4980225539 imp gal |
| 5 gal | 4.1633709231 imp gal |
| 10 gal | 8.3267418463 imp gal |
| 20 gal | 16.6534836926 imp gal |
| 50 gal | 41.6337092314 imp gal |
| 100 gal | 83.2674184629 imp gal |
| 1000 gal | 832.674184629 imp gal |
gal to imp gal chart from 1 to 100
- 1 gal 0.832674 imp gal
- 2 gal 1.66535 imp gal
- 3 gal 2.49802 imp gal
- 4 gal 3.3307 imp gal
- 5 gal 4.16337 imp gal
- 6 gal 4.99605 imp gal
- 7 gal 5.82872 imp gal
- 8 gal 6.66139 imp gal
- 9 gal 7.49407 imp gal
- 10 gal 8.32674 imp gal
- 11 gal 9.15942 imp gal
- 12 gal 9.99209 imp gal
- 13 gal 10.8248 imp gal
- 14 gal 11.6574 imp gal
- 15 gal 12.4901 imp gal
- 16 gal 13.3228 imp gal
- 17 gal 14.1555 imp gal
- 18 gal 14.9881 imp gal
- 19 gal 15.8208 imp gal
- 20 gal 16.6535 imp gal
- 25 gal 20.8169 imp gal
- 30 gal 24.9802 imp gal
- 35 gal 29.1436 imp gal
- 40 gal 33.307 imp gal
- 45 gal 37.4703 imp gal
- 50 gal 41.6337 imp gal
- 55 gal 45.7971 imp gal
- 60 gal 49.9605 imp gal
- 65 gal 54.1238 imp gal
- 70 gal 58.2872 imp gal
- 75 gal 62.4506 imp gal
- 80 gal 66.6139 imp gal
- 85 gal 70.7773 imp gal
- 90 gal 74.9407 imp gal
- 95 gal 79.104 imp gal
- 100 gal 83.2674 imp gal
UK Gallons to US Gallons conversion table
| UK Gallons [imp gal] | US Gallons [gal] |
|---|---|
| 0.01 imp gal | 0.0120094993 gal |
| 0.1 imp gal | 0.1200949926 gal |
| 1 imp gal | 1.2009499255 gal |
| 2 imp gal | 2.401899851 gal |
| 3 imp gal | 3.6028497765 gal |
| 5 imp gal | 6.0047496275 gal |
| 10 imp gal | 12.009499255 gal |
| 20 imp gal | 24.0189985101 gal |
| 50 imp gal | 60.0474962752 gal |
| 100 imp gal | 120.0949925505 gal |
| 1000 imp gal | 1200.9499255049 gal |
US Gallons vs UK Gallons
| US Gallon | UK Gallon | |
|---|---|---|
| Symbol | gal | imp gal |
| Equals | 1 gal = 0.832674 imp gal | 1 imp gal = 1.20095 gal |
What is a US gallon?
A US customary unit equal to 4 quarts. Used in the US for fuel, milk, and paint.
What is a UK gallon?
The imperial gallon, defined as exactly 4.54609 litres (UK Weights and Measures Act 1985); about 20% larger than the US gallon. Used in the UK and Canada for fuel economy (miles per gallon), garden and aquarium volumes, and older fuel prices.
US gallons to imperial gallons
Reading an American recipe, fuel figure or tank size in the UK or Canada? A US gallon is smaller: 1 US gal = 0.832674 imperial gallons, or 3.785 litres.
- A 15-gallon US fuel tank = 12.49 imp gal
- A 5-gallon US bucket = 4.163 imp gal
- 30 mpg (US) ≈ 36 mpg (UK)
The same 5:6 difference runs through pints and fluid ounces, so a US pint (16 fl oz) is also smaller than a UK pint (20 fl oz).
Who Converts US Gallons to UK Gallons?
US gallons are used mainly in the United States, while UK gallons are used mainly in the UK (pub pints, fuel economy in mpg) and older Canadian recipes. Canada and the UK use a mix of metric and imperial units while the US uses customary units, so students, engineers, travellers and shoppers in all three countries switch between them often.
How big is 1 gal compared with 1 imp gal?
1 gal is only 0.832674 of 1 imp gal: you need 1.20095 US gallons to make 1 imp gal, so the number gets smaller when you convert. The two are close in size: 1 imp gal is about 20.1% larger than 1 gal, which is easy to miss.
US Gallons to UK Gallons without a calculator
- In your head: multiply by 0.8 (about 3.9% off). 15 gal × 0.8 ≈ 12 imp gal.
- Closer estimate: multiply by 0.83 (within 0.32%).
- Or divide: divide by 1.2 (within 0.079%), which is often easier than multiplying by a small decimal.
- Fraction trick: multiply by 5, then divide by 6 (within 0.079%).
Real-world gal to imp gal examples
| Example | US Gallons | UK Gallons |
|---|---|---|
| A car fuel tank | 15 gal | 12.4901 imp gal |
| A gallon of milk | 1 gal | 0.832674 imp gal |
| A hot-water heater | 50 gal | 41.6337 imp gal |
| One imperial gallon | 1.20095 gal | 1 imp gal |
| A small aquarium | 12.0095 gal | 10 imp gal |
| A garden water butt | 54.0427 gal | 45 imp gal |
How exact is the gal to imp gal factor?
The factor is exact by definition, so any error comes only from rounding. Round the final answer, not the factor, and match the precision of the number you started with.
Mistakes to avoid
- US and imperial (UK) measures share names but not sizes. Check which one a recipe, label or fuel figure uses before converting.
Background on US gallons and UK gallons
The US gallon is the old English wine gallon of exactly 231 cubic inches.
The imperial gallon was introduced in 1824 and is defined as exactly 4.54609 litres.
Related conversions
Related conversions you may need next: uk gallons to liters, us gallons to liters and liters to uk gallons. The full volume converter lists every unit.
On pakmath.com, the percentage calculator is a useful next step; Adzita offers a free gas mileage calculator.
Frequently asked questions
Is a US gallon smaller than a UK gallon?
Yes. A US gallon is about 83% of an imperial gallon: 3.785 L against 4.546 L.
How many UK gallons is 10 US gallons?
10 US gallons = 8.3267 imperial gallons.
How many UK gallons are in a US gallon?
There are 0.832674 UK gallons in 1 US gallon (1 gal = 0.8326741846 imp gal).
How many US gallons are in a UK gallon?
There are 1.20095 US gallons in 1 UK gallon (1 imp gal = 1.2009499255 gal).
How do I convert US gallons to UK gallons?
Use imp gal = gal × 0.832674. So 10 gal becomes 8.32674 imp gal; for the reverse, multiply by 1.20095.
What is 10 gal in UK gallons?
10 gal = 8.32674 imp gal.
What is 100 gal in UK gallons?
100 gal = 83.2674 imp gal.
Is the gal to imp gal conversion exact?
Yes. The factor comes from the official definitions of both units (NIST Handbook 44, Appendix C, and NIST SP 811 (US customary volume units)). Results are shown to up to 10 decimal places; round them to suit your purpose.
What is an easy way to convert US gallons to UK gallons?
In your head: multiply by 0.8 (about 3.9% off). 15 gal × 0.8 ≈ 12 imp gal.
How many UK gallons is 50 gal (a hot-water heater)?
50 gal = 41.6337 imp gal.
How many US gallons is one imperial gallon (1 imp gal)?
1 imp gal = 1.20095 gal.
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