Gallons (US) to Imperial Gallons Converter
Quick answer: To convert gallons to Imperial Gallons, multiply by 0.8326742. For example, 10 gal is 8.326742 imp gal. One us gallon equals 0.8326742 imp gal.
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Use the Gallons (US) to Imperial Gallons Converter
Gallons (US) to Imperial Gallons formula and what each symbol means
imp gal = gal × 0.8326742
| Symbol | Meaning |
|---|---|
| gal | US gallon |
| imp gal | Imperial gallon |
Gallons (US) to Imperial Gallons examples
1 gal
1 gal × 0.8326742 = 0.8326742 imp gal.
10 gal
10 gal × 0.8326742 = 8.326742 imp gal.
100 gal
100 gal × 0.8326742 = 83.26742 imp gal.
Gallons (US) compared with Imperial Gallons
One imp gal is 1.201 times as large as one gal, so your number gets smaller when you convert gallons to Imperial Gallons and bigger when you convert back. If the answer is not smaller than what you typed, you multiplied instead of dividing.
About gallons and Imperial Gallons
US gallon (gal): The US liquid gallon, exactly 231 cubic inches or 3.785411784 litres. Imperial gallon (imp gal): The imperial (UK) gallon, exactly 4.54609 litres.
Where gallons to Imperial Gallons conversions are used
Cooking and baking move between millilitres, cups, tablespoons and fluid ounces. Fuel, milk and bottled drinks are sold in litres or gallons depending on the country.
How to calculate Gallons (US) to Imperial Gallons step by step
- Enter the value in gal (the starting unit).
- Multiply by 0.8326742, because 1 gal = 0.8326742 imp gal.
- The product is the value in imp gal. To go back, divide by 0.8326742 or multiply by 1.20095.
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How to read your Gallons (US) to Imperial Gallons result
Quick estimate: multiply by about 0.83 to get Imperial Gallons from gallons; this is within 0.4% of the exact factor. The US gallon is exactly 3.785411784 litres and the imperial gallon is exactly 4.54609 litres, about 20% bigger.
| GALLONS (US) | IMPERIAL GALLONS |
|---|---|
| 1 | 0.8326742 |
| 2 | 1.665348 |
| 5 | 4.163371 |
| 10 | 8.326742 |
| 20 | 16.65348 |
| 50 | 41.63371 |
| 100 | 83.26742 |
| 1,000 | 832.6742 |
Imperial Gallons to Gallons (US): quick table
| IMPERIAL GALLONS | GALLONS (US) |
|---|---|
| 1 | 1.20095 |
| 5 | 6.00475 |
| 10 | 12.0095 |
| 25 | 30.02375 |
| 50 | 60.0475 |
| 100 | 120.095 |
| 250 | 300.2375 |
| 500 | 600.475 |
Common mistakes when calculating Gallons (US) to Imperial Gallons
- Using a US gallon where an imperial (UK) gallon is meant, which causes a 20% error.
- Dividing when you should multiply: from gal to imp gal multiply by 0.8326742; from imp gal to gal divide by 0.8326742.
Gallons (US) to Imperial Gallons FAQ
How many imp gal are in 1 gal?
1 gal equals 0.8326742 imp gal.
How many gal are in 1 imp gal?
1 imp gal equals 1.20095 gal.
Is 1 gal = 0.8326742 imp gal an exact conversion?
Yes. The us gallon and the imperial gallon are both defined exactly in SI terms, so the ratio has no measurement uncertainty; 0.8326742 is just that ratio shown to 7 significant figures.
What is an imperial gallon (imp gal)?
The imperial (UK) gallon, exactly 4.54609 litres.
How can I estimate gallons to Imperial Gallons in my head?
Quick estimate: multiply by about 0.83 to get Imperial Gallons from gallons; this is within 0.4% of the exact factor.
What is 75 gal in Imperial Gallons?
75 gal = 62.45056 imp gal (since 75 × 0.8326742).
What is 300 gal in Imperial Gallons?
300 gal = 249.8023 imp gal (since 300 × 0.8326742).
What is 12 gal in Imperial Gallons?
12 gal = 9.99209 imp gal (since 12 × 0.8326742).
How many decimals should I keep when converting gal to imp gal?
Match the precision of your original measurement. For example, 8.326742 imp gal rounds to 8.33 imp gal at 3 significant figures; keep more digits only for engineering or scientific work.
More in Volume converters
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Method, review and disclaimer
Edited by: Hemant Kumar and Anjita Rai, founders of ToolsVault (SEO and content professional, not a licensed adviser). Method: this tool runs in your browser using the formula shown on this page; the numbers you enter are not sent to our servers. Sources: NIST SP 811, Appendix B.8: conversion factors, NIST Handbook 44, Appendix C: units and systems of measurement