US gallon to Imperial fluid ounce Converter
Type a value — the answer appears instantly. 1 gal = 133.23 fl oz (UK).
Reviewed by the OmniCalc teamMethod verified 2026-07-01
133.23 imperial fluid ounces
= 3.78541 L= 3,785.41 ml
equals 133.23 imperial fluid ouncesFormula: fl oz (UK) = gal × 133.22787
US gallon to Imperial fluid ounce formula
fl oz (UK) = gal × 133.22787
Convert 5 US gallons to imperial fluid ounces
- Start with 5 US gallons.
- Multiply by the conversion factor: 5 × 133.228 = 666.14.
- So 5 gal = 666.14 fl oz (UK).
US gallon to Imperial fluid ounce conversion table
| US gallons (gal) | Imperial fluid ounces (fl oz (UK)) |
|---|---|
| 0.01 gal | 1.3323 fl oz (UK) |
| 0.1 gal | 13.323 fl oz (UK) |
| 0.25 gal | 33.307 fl oz (UK) |
| 0.5 gal | 66.614 fl oz (UK) |
| 1 gal | 133.23 fl oz (UK) |
| 2 gal | 266.46 fl oz (UK) |
| 3 gal | 399.68 fl oz (UK) |
| 4 gal | 532.91 fl oz (UK) |
| 5 gal | 666.14 fl oz (UK) |
| 6 gal | 799.37 fl oz (UK) |
| 7 gal | 932.6 fl oz (UK) |
| 8 gal | 1,065.8 fl oz (UK) |
| 9 gal | 1,199.1 fl oz (UK) |
| 10 gal | 1,332.3 fl oz (UK) |
| 15 gal | 1,998.4 fl oz (UK) |
| 20 gal | 2,664.6 fl oz (UK) |
| 25 gal | 3,330.7 fl oz (UK) |
| 30 gal | 3,996.8 fl oz (UK) |
| 40 gal | 5,329.1 fl oz (UK) |
| 50 gal | 6,661.4 fl oz (UK) |
| 75 gal | 9,992.1 fl oz (UK) |
| 100 gal | 13,323 fl oz (UK) |
| 250 gal | 33,307 fl oz (UK) |
| 500 gal | 66,614 fl oz (UK) |
| 1,000 gal | 133,230 fl oz (UK) |
| 5,000 gal | 666,140 fl oz (UK) |
| 10,000 gal | 1,332,300 fl oz (UK) |
Unit definitions
What is a US gallon?
The US gallon is defined as exactly 231 cubic inches, or 3.785411784 litres. It is the standard unit for fuel, milk, and large liquid quantities in the United States. It is about 20% smaller than the imperial gallon.
What is a imperial fluid ounce?
The imperial (UK) fluid ounce is one 160th of an imperial gallon, about 28.41 millilitres. It is used in the United Kingdom and Commonwealth countries. It is slightly smaller than the US fluid ounce.
Frequently asked questions
How many imperial fluid ounces are in one US gallon?
One US gallon equals 133.23 imperial fluid ounces (1 gal = 133.23 fl oz (UK)).
How do I convert US gallons to imperial fluid ounces?
Multiply the value in US gallons by 133.228. For example, 10 gal × 133.228 = 1,332.3 fl oz (UK).
Which is bigger — a US gallon or a imperial fluid ounce?
A US gallon is bigger: one US gallon contains 133.23 imperial fluid ounces.
Is this US gallon to imperial fluid ounce converter free?
Yes — the converter is free, works offline once loaded, and computes instantly in your browser without sending your numbers to a server.
Conversion factors follow international definitions (SI / NIST). Last verified 2026-07-01.