This converter turns imperial fluid ounces into imperial gallons instantly, using the exact factor 1 imperial fluid ounce = 0.00625 imperial gallons. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
The UK fluid ounce, about 4% smaller than its US counterpart. Exactly 4.54609 litres, about 20% larger than the US gallon.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
imperial fluid ounces- The amount you are converting, measured in imperial fluid ounces
0.00625- The exact number of imperial gallons in one imperial fluid ounce
imperial gallons- The converted result
How it works, step by step
- Enter the number of imperial fluid ounces you want to convert.
- The value is multiplied by 0.00625, the exact conversion factor.
- The result is displayed in imperial gallons, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 imperial fluid ounces
Multiply 5 by 0.00625. That gives 0.03125 imperial gallons. A quick sanity check: one imperial fluid ounce is smaller than one imperial gallon, so the number should get smaller — and it does.
Converting 72 imperial fluid ounces
72 × 0.00625 = 0.45 imperial gallons. Working backwards, 0.45 ÷ 0.00625 returns 72 imperial fluid ounces, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many imperial gallons are in one imperial fluid ounce?
Exactly 0.00625. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert imperial fluid ounces to imperial gallons?
Imperial Gallons = imperial fluid ounces × 0.00625. To reverse it, divide instead: imperial fluid ounces = imperial gallons ÷ 0.00625, which is the same as multiplying by 160.
Is the imperial fluid ounce bigger than the imperial gallon?
No. One imperial fluid ounce is only 0.00625 of a imperial gallon, so the imperial gallon is the larger unit.
Why does my answer differ slightly from other imperial-fluid-ounces to imperial-gallons converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a imperial fluid ounce?
The UK fluid ounce, about 4% smaller than its US counterpart.
What is a imperial gallon?
Exactly 4.54609 litres, about 20% larger than the US gallon.
Imperial Fluid Ounces to imperial gallons reference table
| Imperial Fluid Ounces | Imperial Gallons |
|---|---|
| 0.5 fl oz | 0.003125 gal |
| 1 fl oz | 0.00625 gal |
| 2 fl oz | 0.0125 gal |
| 3 fl oz | 0.01875 gal |
| 5 fl oz | 0.03125 gal |
| 10 fl oz | 0.0625 gal |
| 15 fl oz | 0.09375 gal |
| 20 fl oz | 0.125 gal |
| 25 fl oz | 0.15625 gal |
| 50 fl oz | 0.3125 gal |
| 75 fl oz | 0.46875 gal |
| 100 fl oz | 0.625 gal |
| 250 fl oz | 1.5625 gal |
| 500 fl oz | 3.125 gal |
| 1000 fl oz | 6.25 gal |
Exact factor: 1 imperial fluid ounce = 0.00625 imperial gallons. Values rounded for display.