An imperial fluid ounce is 1/160 of an imperial gallon.
Imperial fluid ounces to Cubic inches Converter — imp fl oz to in3
Convert Imperial fluid ounce (imp fl oz) to Cubic inch (in3) using the exact conversion factor (1 imperial fluid ounce = 1.733871455 cubic inch). See the formula, worked examples, conversion table, history, and common uses.
Imperial fluid ounces to Cubic inches 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 cubic inch is the volume of a one-inch cube.
Result = input x 2.84130625e-5 / 1.6387064e-5.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Imperial fluid ounces to Cubic inches
Imperial fluid ounce and Cubic inch 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. Imperial fluid ounce is most often used for uk/commonwealth beverage measurement in historical or specialized contexts.
Formula
cubic inches = imperial fluid ounces × 1.73387145495
This factor comes from each unit's defined relationship to the category's base unit: 1 imperial fluid ounce equals 0.0000284130625 base units, and 1 cubic inch equals 0.000016387064 base units, so dividing one by the other gives the direct imperial fluid ounce-to-cubic inch factor of 1.73387145495.
Simple example
1 imp fl oz × 1.733871455 = 1.733871455 in3
1 imperial fluid ounce = 1.733871455 cubic inches.
Real-world example
10 imp fl oz × 1.733871455 = 17.33871455 in3
10 imperial fluid ounces = 17.33871455 cubic inches.
Conversion table
| Imperial fluid ounce (imp fl oz) | Cubic inch (in3) |
|---|---|
| 1 imp fl oz | 1.733871455 in3 |
| 5 imp fl oz | 8.669357275 in3 |
| 10 imp fl oz | 17.33871455 in3 |
| 25 imp fl oz | 43.34678637 in3 |
| 50 imp fl oz | 86.69357275 in3 |
| 100 imp fl oz | 173.3871455 in3 |
Reverse conversion: Cubic inch to Imperial fluid ounce
1.733871455 in3 × 0.576744024 = 1 imp fl oz
1.733871455 cubic inches = 1 imperial fluid ounces.
imperial fluid ounces = cubic inches × 0.576744023985
For a page dedicated to this direction, see Cubic inch to Imperial fluid ounce.
Understanding the Imperial fluid ounce
Imperial fluid ounce (imp fl oz) measures volume. The imperial fluid ounce is 1/160 of an imperial gallon: exactly 28.4130625 milliliters — slightly smaller than the US fluid ounce despite the larger imperial gallon, because it divides that gallon into more parts. It is classified as a UK/imperial customary unit.
Where it's used: United Kingdom (historically; less common in current UK retail than metric units)
Imperial fluid ounce vs. US fluid ounce. Confusingly, the imperial fluid ounce (28.41 mL) is slightly smaller than the US fluid ounce (29.57 mL), even though the imperial gallon is larger overall — because the imperial gallon is divided into 160 fluid ounces rather than the US gallon's 128.
Uses of the Imperial fluid ounce today
- UK/Commonwealth beverage measurement in historical or specialized contexts
History of the Imperial fluid ounce
The imperial fluid ounce follows from Britain's 1824 imperial gallon, divided into 160 parts rather than the 128 used in the US system, producing its counterintuitively smaller size relative to the US fluid ounce.
Historical origin. Imperial fluid ounce was not the invention of a single named person; it developed through the process described above.
Understanding the Cubic inch (in3)
A cubic inch is the volume of a one-inch cube.
Imperial fluid ounce — sources
- UK Weights and Measures Act 1824 — Basis for the imperial fluid ounce via the imperial gallon.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many cubic inches are in 1 imperial fluid ounce?
1 imperial fluid ounce equals 1.733871455 cubic inches, using the exact defined conversion factor rather than an estimate.
How do I convert imperial fluid ounce to cubic inch?
Multiply the imperial fluid ounce value by 1.733871455. The converter above does this instantly to whatever precision you set.
How do I convert cubic inch back to imperial fluid ounce?
Use the reverse factor: 1 cubic inch equals 0.576744024 imperial fluid ounces. You can also use the swap control in the converter above to flip the direction instantly.
What is a imperial fluid ounce?
Imperial fluid ounce (imp fl oz) measures volume. The imperial fluid ounce is 1/160 of an imperial gallon: exactly 28.4130625 milliliters — slightly smaller than the US fluid ounce despite the larger imperial gallon, because it divides that gallon into more parts. It is classified as a UK/imperial customary unit.
What is a cubic inch?
Cubic inch (in3) is a unit of volume.
Is the imperial fluid ounce to cubic inch conversion exact?
Yes. The imperial fluid ounce is 1/160 of an imperial gallon: exactly 28.4130625 milliliters — slightly smaller than the US fluid ounce despite the larger imperial gallon, because it divides that gallon into more parts. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between imperial fluid ounce vs. us fluid ounce?
Confusingly, the imperial fluid ounce (28.41 mL) is slightly smaller than the US fluid ounce (29.57 mL), even though the imperial gallon is larger overall — because the imperial gallon is divided into 160 fluid ounces rather than the US gallon's 128.
Where is the imperial fluid ounce still used today?
United Kingdom (historically; less common in current UK retail than metric units)