This converter turns cubic inches into US fluid ounces instantly, using the exact factor 1 cubic inch = 0.5541125541 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 volume of a one-inch cube, traditional for US engine displacement. 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
cubic inches- The amount you are converting, measured in cubic inches
0.5541125541- The exact number of US fluid ounces in one cubic inch
US fluid ounces- The converted result
How it works, step by step
- Enter the number of cubic inches you want to convert.
- The value is multiplied by 0.5541125541, 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 cubic inches
Multiply 5 by 0.55411255. That gives 2.7706 US fluid ounces. A quick sanity check: one cubic inch is smaller than one US fluid ounce, so the number should get smaller — and it does.
Converting 72 cubic inches
72 × 0.55411255 = 39.8961 US fluid ounces. Working backwards, 39.8961 ÷ 0.55411255 returns 72 cubic inches, 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 cubic inch?
Exactly 0.5541125541. 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 cubic inches to US fluid ounces?
Us Fluid Ounces = cubic inches × 0.5541125541. To reverse it, divide instead: cubic inches = US fluid ounces ÷ 0.5541125541, which is the same as multiplying by 1.8046875.
Is the cubic inch bigger than the US fluid ounce?
No. One cubic inch is only 0.554113 of a US fluid ounce, so the US fluid ounce is the larger unit.
Why does my answer differ slightly from other cubic-inches 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 cubic inch?
The volume of a one-inch cube, traditional for US engine displacement.
What is a US fluid ounce?
One eighth of a US cup, roughly 29.57 millilitres.
Cubic Inches to US fluid ounces reference table
| Cubic Inches | Us Fluid Ounces |
|---|---|
| 0.5 in³ | 0.277056 fl oz |
| 1 in³ | 0.554113 fl oz |
| 2 in³ | 1.1082 fl oz |
| 3 in³ | 1.6623 fl oz |
| 5 in³ | 2.7706 fl oz |
| 10 in³ | 5.5411 fl oz |
| 15 in³ | 8.3117 fl oz |
| 20 in³ | 11.0823 fl oz |
| 25 in³ | 13.8528 fl oz |
| 50 in³ | 27.7056 fl oz |
| 75 in³ | 41.5584 fl oz |
| 100 in³ | 55.4113 fl oz |
| 250 in³ | 138.5281 fl oz |
| 500 in³ | 277.0563 fl oz |
| 1000 in³ | 554.1126 fl oz |
Exact factor: 1 cubic inch = 0.5541125541 US fluid ounces. Values rounded for display.