This converter turns imperial fluid ounces into US fluid ounces instantly, using the exact factor 1 imperial fluid ounce = 0.9607599404 US fluid ounces. 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. One eighth of a US cup, roughly 29.57 millilitres.
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
0.9607599404- The exact number of US fluid ounces in one imperial fluid ounce
US fluid ounces- 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 0.9607599404, the exact conversion factor.
- The result is displayed in US fluid ounces, 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 0.96075994. That gives 4.8038 US fluid ounces. A quick sanity check: one imperial fluid ounce is smaller than one US fluid ounce, so the number should get smaller — and it does.
Converting 72 imperial fluid ounces
72 × 0.96075994 = 69.1747 US fluid ounces. Working backwards, 69.1747 ÷ 0.96075994 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 US fluid ounces are in one imperial fluid ounce?
Exactly 0.9607599404. 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 US fluid ounces?
Us Fluid Ounces = imperial fluid ounces × 0.9607599404. To reverse it, divide instead: imperial fluid ounces = US fluid ounces ÷ 0.9607599404, which is the same as multiplying by 1.040842731.
Is the imperial fluid ounce bigger than the US fluid ounce?
No. One imperial fluid ounce is only 0.96076 of a US fluid ounce, so the US fluid ounce is the larger unit.
Why does my answer differ slightly from other imperial-fluid-ounces to us-fluid-ounces 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 US fluid ounce?
One eighth of a US cup, roughly 29.57 millilitres.
Imperial Fluid Ounces to US fluid ounces reference table
| Imperial Fluid Ounces | Us Fluid Ounces |
|---|---|
| 0.5 fl oz | 0.48038 fl oz |
| 1 fl oz | 0.96076 fl oz |
| 2 fl oz | 1.9215 fl oz |
| 3 fl oz | 2.8823 fl oz |
| 5 fl oz | 4.8038 fl oz |
| 10 fl oz | 9.6076 fl oz |
| 15 fl oz | 14.4114 fl oz |
| 20 fl oz | 19.2152 fl oz |
| 25 fl oz | 24.019 fl oz |
| 50 fl oz | 48.038 fl oz |
| 75 fl oz | 72.057 fl oz |
| 100 fl oz | 96.076 fl oz |
| 250 fl oz | 240.19 fl oz |
| 500 fl oz | 480.38 fl oz |
| 1000 fl oz | 960.7599 fl oz |
Exact factor: 1 imperial fluid ounce = 0.9607599404 US fluid ounces. Values rounded for display.