UK Gallons to US Gallons (imp gal to gal) Converter
1 UK gallon (imp gal) = 1.20095 US gallons (gal). To convert UK gallons to US gallons, multiply by 1.20095: 25 imp gal × 1.20095 = 30.0237 gal. Also searched as imperial gallon to US gallon, UK vs US gallon.
Quick facts
- 1 imp gal = 1.20095 gal
- 1 gal = 0.832674 imp gal
- Formula: gal = imp gal × 1.20095
- Quick estimate: multiply by about 1.2
How to convert UK gallons to US gallons
- Take the value in UK gallons.
- Multiply it by 1.20095 (the number of US gallons in one UK gallon).
- Round the answer to a sensible number of decimal places.
Worked example: 25 imp gal × 1.20095 = 30.0237 gal.
To convert US gallons back to UK gallons, multiply by 0.832674, or divide by 1.20095.
Source: NIST Handbook 44, Appendix C, and NIST SP 811 (US customary volume units).
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 |
imp gal to gal chart from 1 to 100
- 1 imp gal 1.20095 gal
- 2 imp gal 2.4019 gal
- 3 imp gal 3.60285 gal
- 4 imp gal 4.8038 gal
- 5 imp gal 6.00475 gal
- 6 imp gal 7.2057 gal
- 7 imp gal 8.40665 gal
- 8 imp gal 9.6076 gal
- 9 imp gal 10.8085 gal
- 10 imp gal 12.0095 gal
- 11 imp gal 13.2104 gal
- 12 imp gal 14.4114 gal
- 13 imp gal 15.6123 gal
- 14 imp gal 16.8133 gal
- 15 imp gal 18.0142 gal
- 16 imp gal 19.2152 gal
- 17 imp gal 20.4161 gal
- 18 imp gal 21.6171 gal
- 19 imp gal 22.818 gal
- 20 imp gal 24.019 gal
- 25 imp gal 30.0237 gal
- 30 imp gal 36.0285 gal
- 35 imp gal 42.0332 gal
- 40 imp gal 48.038 gal
- 45 imp gal 54.0427 gal
- 50 imp gal 60.0475 gal
- 55 imp gal 66.0522 gal
- 60 imp gal 72.057 gal
- 65 imp gal 78.0617 gal
- 70 imp gal 84.0665 gal
- 75 imp gal 90.0712 gal
- 80 imp gal 96.076 gal
- 85 imp gal 102.081 gal
- 90 imp gal 108.085 gal
- 95 imp gal 114.09 gal
- 100 imp gal 120.095 gal
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 |
UK Gallons vs US Gallons
| UK Gallon | US Gallon | |
|---|---|---|
| Symbol | imp gal | gal |
| Equals | 1 imp gal = 1.20095 gal | 1 gal = 0.832674 imp gal |
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.
What is a US gallon?
A US customary unit equal to 4 quarts. Used in the US for fuel, milk, and paint.
Why UK and US gallons differ
The US kept the old English wine gallon of 231 cubic inches, while Britain introduced the larger imperial gallon in 1824. Canada used imperial gallons until it went metric in the 1970s. The result: 1 imperial gallon = 1.20095 US gallons.
This matters most for fuel economy. A car rated at 40 mpg in the UK does only about 33.31 mpg in US terms, because each UK gallon holds more fuel.
- UK mpg × 0.8327 = US mpg
- US mpg × 1.2009 = UK mpg
Who Converts UK Gallons to US Gallons?
UK gallons are used mainly in the UK (pub pints, fuel economy in mpg) and older Canadian recipes, while US gallons are used mainly in the United States. 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 imp gal compared with 1 gal?
1 imp gal is 1.20095 times the size of 1 gal, so the number gets bigger when you convert UK gallons to US gallons. The two are close in size: 1 imp gal is about 20.1% larger than 1 gal, which is easy to miss.
UK Gallons to US Gallons without a calculator
- Closer estimate: multiply by 1.2 (within 0.079%).
- Fraction trick: multiply by 6, then divide by 5 (within 0.079%).
Real-world imp gal to gal examples
| Example | UK Gallons | US Gallons |
|---|---|---|
| One imperial gallon | 1 imp gal | 1.20095 gal |
| A small aquarium | 10 imp gal | 12.0095 gal |
| A garden water butt | 45 imp gal | 54.0427 gal |
| A car fuel tank | 12.4901 imp gal | 15 gal |
| A gallon of milk | 0.832674 imp gal | 1 gal |
| A hot-water heater | 41.6337 imp gal | 50 gal |
How exact is the imp gal to gal factor?
The factor is exact by definition, so any error comes only from rounding. Keep at least 4 significant figures for school work, and the full factor for anything legal or commercial.
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 UK gallons and US gallons
The imperial gallon was introduced in 1824 and is defined as exactly 4.54609 litres.
The US gallon is the old English wine gallon of exactly 231 cubic inches.
What people convert next
Next, you might want us gallons to liters, uk gallons to liters and liters to us gallons. The full volume converter lists every unit.
On pakmath.com, the percentage calculator is a useful next step, as is the scientific calculator; for related everyday maths, try the gas mileage calculator on Adzita.
Frequently asked questions
How many US gallons are in an imperial gallon?
1 imperial gallon = 1.20095 US gallons.
How do I convert UK mpg to US mpg?
Multiply UK mpg by 0.8327. For example, 50 mpg (UK) is about 41.6 mpg (US).
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 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 do I convert UK gallons to US gallons?
Use gal = imp gal × 1.20095. So 10 imp gal becomes 12.0095 gal; for the reverse, multiply by 0.832674.
What is 10 imp gal in US gallons?
10 imp gal = 12.0095 gal.
What is 100 imp gal in US gallons?
100 imp gal = 120.095 gal.
Is the 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 UK gallons to US gallons?
Closer estimate: multiply by 1.2 (within 0.079%).
How many US gallons is 45 imp gal (a garden water butt)?
45 imp gal = 54.0427 gal.
How many UK gallons is a gallon of milk (1 gal)?
1 gal = 0.832674 imp gal.
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