This converter turns imperial fluid ounces into cubic inches instantly, using the exact factor 1 imperial fluid ounce = 1.733871455 cubic inches. 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. The volume of a one-inch cube, traditional for US engine displacement.
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
1.733871455- The exact number of cubic inches in one imperial fluid ounce
cubic inches- 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 1.733871455, the exact conversion factor.
- The result is displayed in cubic inches, 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 1.7338715. That gives 8.6694 cubic inches. A quick sanity check: one imperial fluid ounce is larger than one cubic inch, so the number should get bigger — and it does.
Converting 72 imperial fluid ounces
72 × 1.7338715 = 124.8387 cubic inches. Working backwards, 124.8387 ÷ 1.7338715 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 cubic inches are in one imperial fluid ounce?
Exactly 1.733871455. 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 cubic inches?
Cubic Inches = imperial fluid ounces × 1.733871455. To reverse it, divide instead: imperial fluid ounces = cubic inches ÷ 1.733871455, which is the same as multiplying by 0.576744024.
Is the imperial fluid ounce bigger than the cubic inch?
Yes. One imperial fluid ounce equals 1.73387 cubic inches, so it is the larger unit.
Why does my answer differ slightly from other imperial-fluid-ounces to cubic-inches 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 cubic inch?
The volume of a one-inch cube, traditional for US engine displacement.
Imperial Fluid Ounces to cubic inches reference table
| Imperial Fluid Ounces | Cubic Inches |
|---|---|
| 0.5 fl oz | 0.866936 in³ |
| 1 fl oz | 1.7339 in³ |
| 2 fl oz | 3.4677 in³ |
| 3 fl oz | 5.2016 in³ |
| 5 fl oz | 8.6694 in³ |
| 10 fl oz | 17.3387 in³ |
| 15 fl oz | 26.0081 in³ |
| 20 fl oz | 34.6774 in³ |
| 25 fl oz | 43.3468 in³ |
| 50 fl oz | 86.6936 in³ |
| 75 fl oz | 130.0404 in³ |
| 100 fl oz | 173.3871 in³ |
| 250 fl oz | 433.4679 in³ |
| 500 fl oz | 866.9357 in³ |
| 1000 fl oz | 1,733.87 in³ |
Exact factor: 1 imperial fluid ounce = 1.733871455 cubic inches. Values rounded for display.