Convert US fluid ounces to Cubic inches
1 US fluid ounce is 1.8 in³. One US fluid ounce is exactly 1.8046875 cubic inches.
One US fluid ounce is 1.8046875 cubic inches. To convert US fluid ounces to cubic inches, multiply by 1.8046875; to go the other way, divide by 1.8046875 or multiply by 0.55411255. The factor is exact rather than rounded: it follows from NIST Handbook 130. Exactly one 128th of a US gallon, which makes it 29.5735295625 ml exactly.
Factor checked against the defining standard · How we check
- US fluid ounces × 1.8046875
1 * 1.80468751.805 in³
1 US fluid ounce in every volume unit
| Unit | Value | Exact factor |
|---|---|---|
| US teaspoons | 6 tsp | × 6 |
| US tablespoons | 2 tbsp | × 2 |
| US fluid ounces (as entered) | 1 fl oz | — |
| US cups | 0.125 cup | × 0.125 |
| US pints | 0.0625 pt | × 0.0625 |
| US quarts | 0.03125 qt | × 0.03125 |
| US gallons | 0.0078125 gal | × 0.0078125 |
| milliliters | 29.57352956 ml | × 29.5735295625 |
| liters | 0.02957352956 L | × 0.0295735295625 |
| imperial gallons | 0.006505267067 gal (UK) | × 0.00650526706741 |
| imperial quarts | 0.02602106827 qt (UK) | × 0.0260210682697 |
| imperial pints | 0.05204213654 pt (UK) | × 0.0520421365393 |
| imperial fluid ounces | 1.040842731 fl oz (UK) | × 1.04084273079 |
| imperial gills | 0.2081685462 gi (UK) | × 0.208168546157 |
| cubic millimetres | 29,573.52956 mm³ | × 29,573.5295625 |
| cubic centimetres | 29.57352956 cm³ | × 29.5735295625 |
| cubic inches | 1.8046875 in³ | × 1.8046875 |
| cubic feet | 0.00104437934 ft³ | × 0.00104437934028 |
| cubic yards | 0.00003868071631 yd³ | × 0.0000386807163066 |
| cubic metres | 0.00002957352956 m³ | × 0.0000295735295625 |
Factors are entered by hand from NIST Handbook 130 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert US fluid ounces to cubic inches? The converter and the working
- 1.Take the measurement in US fluid ounces.
- 2.Multiply by 1.8046875 — that is how many cubic inches fit in one US fluid ounce.
- 3.To go back the other way, divide by 1.8046875, or multiply by 0.55411255.
Worked example: 25 US fluid ounces to cubic inches
- Formula
- fl oz × 1.8046875 = in³
- Arithmetic
- 25 × 1.8046875 = 45.12 in³
- Answer
- 25 fl oz = 45.12 in³
The factor is exact, so this figure is exact too — only the display is rounded.
US fluid ounces to cubic inches conversion table
| US fluid ounces | Cubic inches |
|---|---|
| 1 fl oz | 1.8 in³ |
| 2 fl oz | 3.61 in³ |
| 3 fl oz | 5.41 in³ |
| 4 fl oz | 7.22 in³ |
| 5 fl oz | 9.02 in³ |
| 6 fl oz | 10.83 in³ |
| 7 fl oz | 12.63 in³ |
| 8 fl oz | 14.44 in³ |
| 9 fl oz | 16.24 in³ |
| 10 fl oz | 18.05 in³ |
| 12 fl oz | 21.66 in³ |
| 15 fl oz | 27.07 in³ |
| 20 fl oz | 36.09 in³ |
| 25 fl oz | 45.12 in³ |
| 50 fl oz | 90.23 in³ |
| 100 fl oz | 180.47 in³ |
| 200 fl oz | 360.94 in³ |
| 300 fl oz | 541.41 in³ |
| 500 fl oz | 902.34 in³ |
| 1000 fl oz | 1,804.69 in³ |
| 2000 fl oz | 3,609.38 in³ |
| 5000 fl oz | 9,023.44 in³ |
| 10000 fl oz | 18,046.88 in³ |
What is a US fluid ounce?
Exactly one 128th of a US gallon, which makes it 29.5735295625 ml exactly. The imperial fluid ounce is a different unit at exactly 28.4130625 ml, so a UK recipe calling for 10 fl oz means 284 ml and a US one means 296 ml. It is also a volume, not a weight: an ounce of flour is not a fluid ounce of flour.
What is a cubic inch?
Exactly 16.387064 millilitres, since the inch is exactly 25.4 mm. American engine displacement was quoted in it until the 1980s — a 350 small block is 5.7 litres.
How many cubic inches are in a US fluid ounce?
One US fluid ounce is 1.8046875 cubic inches, exactly. Going the other way, one cubic inch is 0.55411255 US fluid ounces. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every volume unit here
The whole group — 20 units with their symbols and the size of each one in liters — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a US fluid ounce.
Cite this page
- APA
- Rule Calculator. (2026). Convert US fluid ounces to cubic inches. Rule Calculator. https://rulecalculators.com/convert/fluid-ounce-to-cubic-inch
- MLA
- "Convert US fluid ounces to cubic inches." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/fluid-ounce-to-cubic-inch.
- Chicago
- Rule Calculator. "Convert US fluid ounces to cubic inches." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/fluid-ounce-to-cubic-inch.
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Questions people actually ask
- How many cubic inches are in a US fluid ounce?
- 1.8046875. Exactly 16.387064 millilitres, since the inch is exactly 25.4 mm. American engine displacement was quoted in it until the 1980s — a 350 small block is 5.7 litres.
- How do I convert cubic inches back to US fluid ounces?
- Divide by 1.8046875, or multiply by 0.55411255 — they are the same operation.
Other volume conversions
Cubic inches to US fluid ounces — the same conversion the other way.