A cubic inch is the volume of a one-inch cube.
Cubic inches to Fluid ounces Converter — in3 to fl oz
Convert Cubic inch (in3) to Fluid ounce (fl oz) using the exact conversion factor (1 cubic inch = 0.5541125541 fluid ounce). See the formula, worked examples, conversion table, history, and common uses.
Cubic inches to Fluid ounces converter
Converter
Volume Converter
Convert metric, US customary, imperial, cooking, dry, and industrial volume units.
Context values
Some unit families need one extra value for a physically accurate result.
A US fluid ounce is 1/128 of a US gallon.
Result = input x 1.6387064e-5 / 2.95735296e-5.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Cubic inches to Fluid ounces
Cubic inch and Fluid ounce appear side by side at fuel pumps and on beverage labels, since the US measures liquids in gallons while most of the world uses liters. Specifically: A cubic inch is the volume of a one-inch cube, and a US fluid ounce is 1/128 of a US gallon.
Formula
fluid ounces = cubic inches × 0.554112554113
This factor comes from each unit's defined relationship to the category's base unit: 1 cubic inch equals 0.000016387064 base units, and 1 fluid ounce equals 0.0000295735295625 base units, so dividing one by the other gives the direct cubic inch-to-fluid ounce factor of 0.554112554113.
Simple example
1 in3 × 0.5541125541 = 0.5541125541 fl oz
1 cubic inch = 0.5541125541 fluid ounces.
Real-world example
10 in3 × 0.5541125541 = 5.541125541 fl oz
10 cubic inches = 5.541125541 fluid ounces.
Conversion table
| Cubic inch (in3) | Fluid ounce (fl oz) |
|---|---|
| 1 in3 | 0.5541125541 fl oz |
| 5 in3 | 2.770562771 fl oz |
| 10 in3 | 5.541125541 fl oz |
| 25 in3 | 13.85281385 fl oz |
| 50 in3 | 27.70562771 fl oz |
| 100 in3 | 55.41125541 fl oz |
Reverse conversion: Fluid ounce to Cubic inch
0.5541125541 fl oz × 1.8046875 = 1 in3
0.5541125541 fluid ounces = 1 cubic inches.
cubic inches = fluid ounces × 1.8046875
For a page dedicated to this direction, see Fluid ounce to Cubic inch.
Understanding the Cubic inch (in3)
A cubic inch is the volume of a one-inch cube.
Understanding the Fluid ounce
Fluid ounce (fl oz) measures volume. The US fluid ounce is 1/128 of a US gallon: exactly 29.5735295625 milliliters. It is classified as a US customary unit.
Where it's used: United States (beverage, nutrition labeling)
Uses of the Fluid ounce today
- US beverage container sizing (soda, water bottles)
- US nutrition and medication dosing labels
History of the Fluid ounce
The US fluid ounce follows from the same English wine-gallon system as the rest of the US liquid volume units, defined as a consistent fraction of the gallon.
Historical origin. Fluid ounce was not the invention of a single named person; it developed through the process described above.
Fluid ounce — sources
- NIST Handbook 44, Appendix C — General tables of units including the US fluid ounce definition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many fluid ounces are in 1 cubic inch?
1 cubic inch equals 0.5541125541 fluid ounces, using the exact defined conversion factor rather than an estimate.
How do I convert cubic inch to fluid ounce?
Multiply the cubic inch value by 0.5541125541. The converter above does this instantly to whatever precision you set.
How do I convert fluid ounce back to cubic inch?
Use the reverse factor: 1 fluid ounce equals 1.8046875 cubic inches. You can also use the swap control in the converter above to flip the direction instantly.
What is a cubic inch?
Cubic inch (in3) is a unit of volume.
What is a fluid ounce?
Fluid ounce (fl oz) measures volume. The US fluid ounce is 1/128 of a US gallon: exactly 29.5735295625 milliliters. It is classified as a US customary unit.
Is the cubic inch to fluid ounce conversion exact?
Yes. The US fluid ounce is 1/128 of a US gallon: exactly 29.5735295625 milliliters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.