Convert Imperial gallons to US fluid ounces
1 imperial gallon is 153.72 fl oz. One imperial gallon is exactly 153.721590465 US fluid ounces.
One imperial gallon is 153.72159 US fluid ounces. To convert imperial gallons to US fluid ounces, multiply by 153.72159; to go the other way, divide by 153.72159 or multiply by 0.0065052671. The relation is exact but the figure is not: it is a rounding of a number that does not terminate, and it follows from NIST Handbook 130.
Factor checked against the defining standard · How we check
- Imperial gallons × 153.72159
1 * 153.72159153.722 fl oz
1 imperial gallon in every volume unit
| Unit | Value | Exact factor |
|---|---|---|
| US teaspoons | 922.3295428 tsp | × 922.329542788 |
| US tablespoons | 307.4431809 tbsp | × 307.443180929 |
| US fluid ounces | 153.7215905 fl oz | × 153.721590465 |
| US cups | 19.21519881 cup | × 19.2151988081 |
| US pints | 9.607599404 pt | × 9.60759940404 |
| US quarts | 4.803799702 qt | × 4.80379970202 |
| US gallons | 1.200949926 gal | × 1.2009499255 |
| milliliters | 4,546.09 ml | × 4,546.09 |
| liters | 4.54609 L | × 4.54609 |
| imperial gallons (as entered) | 1 gal (UK) | — |
| imperial quarts | 4 qt (UK) | × 4 |
| imperial pints | 8 pt (UK) | × 8 |
| imperial fluid ounces | 160 fl oz (UK) | × 160 |
| imperial gills | 32 gi (UK) | × 32 |
| cubic millimetres | 4,546,090 mm³ | × 4,546,090 |
| cubic centimetres | 4,546.09 cm³ | × 4,546.09 |
| cubic inches | 277.4194328 in³ | × 277.419432792 |
| cubic feet | 0.1605436532 ft³ | × 0.160543653236 |
| cubic yards | 0.005946061231 yd³ | × 0.00594606123096 |
| cubic metres | 0.00454609 m³ | × 0.00454609 |
Factors are entered by hand from NIST Handbook 130 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert imperial gallons to US fluid ounces? The converter and the working
- 1.Take the measurement in imperial gallons.
- 2.Multiply by 153.72159 — that is how many US fluid ounces fit in one imperial gallon.
- 3.To go back the other way, divide by 153.72159, or multiply by 0.0065052671.
Worked example: 25 imperial gallons to US fluid ounces
- Formula
- gal (UK) × 153.72159 = fl oz
- Arithmetic
- 25 × 153.72159 = 3,843.04 fl oz
- Answer
- 25 gal (UK) = 3,843.04 fl oz
The factor is rounded for display; the figure above is computed from the full value.
Imperial gallons to US fluid ounces conversion table
| Imperial gallons | US fluid ounces |
|---|---|
| 1 gal (UK) | 153.72 fl oz |
| 2 gal (UK) | 307.44 fl oz |
| 3 gal (UK) | 461.16 fl oz |
| 4 gal (UK) | 614.89 fl oz |
| 5 gal (UK) | 768.61 fl oz |
| 6 gal (UK) | 922.33 fl oz |
| 7 gal (UK) | 1,076.05 fl oz |
| 8 gal (UK) | 1,229.77 fl oz |
| 9 gal (UK) | 1,383.49 fl oz |
| 10 gal (UK) | 1,537.22 fl oz |
| 12 gal (UK) | 1,844.66 fl oz |
| 15 gal (UK) | 2,305.82 fl oz |
| 20 gal (UK) | 3,074.43 fl oz |
| 25 gal (UK) | 3,843.04 fl oz |
| 50 gal (UK) | 7,686.08 fl oz |
| 100 gal (UK) | 15,372.16 fl oz |
| 200 gal (UK) | 30,744.32 fl oz |
| 300 gal (UK) | 46,116.48 fl oz |
| 500 gal (UK) | 76,860.8 fl oz |
| 1000 gal (UK) | 153,721.59 fl oz |
| 2000 gal (UK) | 307,443.18 fl oz |
| 5000 gal (UK) | 768,607.95 fl oz |
| 10000 gal (UK) | 1,537,215.9 fl oz |
What is an imperial gallon?
Exactly 4.54609 liters since 1985, and the reason UK and US fuel economy figures cannot be compared: it is 20% larger than the US gallon, so 40 mpg in Britain is about 33 mpg in America on the same car.
What is a US fluid ounce?
Exactly one 128th of a US gallon, which makes it 29.5735295625 ml exactly. The imperial fluid ounce is a different unit at exactly 28.4130625 ml, so a UK recipe calling for 10 fl oz means 284 ml and a US one means 296 ml. It is also a volume, not a weight: an ounce of flour is not a fluid ounce of flour.
How many US fluid ounces are in an imperial gallon?
One imperial gallon is 153.72159 US fluid ounces. Going the other way, one US fluid ounce is 0.0065052671 imperial gallons. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every volume unit here
The whole group — 20 units with their symbols and the size of each one in liters — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to an imperial gallon.
Cite this page
- APA
- Rule Calculator. (2026). Convert Imperial gallons to US fluid ounces. Rule Calculator. https://rulecalculators.com/convert/imperial-gallon-to-fluid-ounce
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- Chicago
- Rule Calculator. "Convert Imperial gallons to US fluid ounces." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/imperial-gallon-to-fluid-ounce.
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Questions people actually ask
- How many US fluid ounces are in an imperial gallon?
- 153.72159. Exactly one 128th of a US gallon, which makes it 29.5735295625 ml exactly. The imperial fluid ounce is a different unit at exactly 28.4130625 ml, so a UK recipe calling for 10 fl oz means 284 ml and a US one means 296 ml. It is also a volume, not a weight: an ounce of flour is not a fluid ounce of flour.
- How do I convert US fluid ounces back to imperial gallons?
- Divide by 153.72159, or multiply by 0.0065052671 — they are the same operation.
Other volume conversions
US fluid ounces to imperial gallons — the same conversion the other way.