A US customary cup is 236.5882365 milliliters.
Cups to Imperial fluid ounces Converter — cup to imp fl oz
Convert Cup (cup) to Imperial fluid ounce (imp fl oz) using the exact conversion factor (1 cup = 8.326741846 imperial fluid ounce). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Cups to Imperial 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.
An imperial fluid ounce is 1/160 of an imperial gallon.
Result = input x 0.0002365882365 / 2.84130625e-5.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Cups to Imperial fluid ounces
Cup and Imperial 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. Cup is typically associated with united States (recipes and cooking measurement), while Imperial fluid ounce is typically associated with united Kingdom (historically; less common in current UK retail than metric units).
Formula
imperial fluid ounces = cups × 8.32674184629
This factor comes from each unit's defined relationship to the category's base unit: 1 cup equals 0.0002365882365 base units, and 1 imperial fluid ounce equals 0.0000284130625 base units, so dividing one by the other gives the direct cup-to-imperial fluid ounce factor of 8.32674184629.
Simple example
1 cup × 8.326741846 = 8.326741846 imp fl oz
1 cup = 8.326741846 imperial fluid ounces.
Real-world example
10 cup × 8.326741846 = 83.26741846 imp fl oz
10 cups = 83.26741846 imperial fluid ounces.
Conversion table
| Cup (cup) | Imperial fluid ounce (imp fl oz) |
|---|---|
| 1 cup | 8.326741846 imp fl oz |
| 5 cup | 41.63370923 imp fl oz |
| 10 cup | 83.26741846 imp fl oz |
| 25 cup | 208.1685462 imp fl oz |
| 50 cup | 416.3370923 imp fl oz |
| 100 cup | 832.6741846 imp fl oz |
Reverse conversion: Imperial fluid ounce to Cup
8.326741846 imp fl oz × 0.1200949926 = 1 cup
8.326741846 imperial fluid ounces = 1 cups.
cups = imperial fluid ounces × 0.12009499255
For a page dedicated to this direction, see Imperial fluid ounce to Cup.
Cup vs. Imperial fluid ounce
| Aspect | Cup | Imperial fluid ounce |
|---|---|---|
| Family | US customary unit (culinary) | UK/imperial customary unit |
| Typical use | US recipe and cooking measurement | UK/Commonwealth beverage measurement in historical or specialized contexts |
| Where it's used | United States (recipes and cooking measurement) | United Kingdom (historically; less common in current UK retail than metric units) |
Understanding the Cup
Cup (cup) measures volume. The US customary cup used in cooking is defined as exactly 240 milliliters (a rounded culinary standard, not the older 236.588 mL legal cup). It is classified as a US customary unit (culinary).
Where it's used: United States (recipes and cooking measurement)
Cooking cup vs. legal US cup. US recipes commonly round the cup to 240 mL for convenience, while the precise legal US cup (used to derive fluid ounces, pints, etc.) is 236.588 mL — a small but sometimes noticeable difference in precise baking.
Uses of the Cup today
- US recipe and cooking measurement
- Nutrition labeling serving sizes
- Baking, where volume-based flour/sugar measurement is still common in the US
History of the Cup
The cup as a cooking measure grew out of household and community cookbook conventions in 19th-century America, standardizing what had been ad hoc measurements ('a teacup of flour') into a fixed volume.
The US FDA uses a rounded 240 mL 'metric cup' for nutrition labeling purposes, distinct from the slightly smaller legal/customary cup (236.588 mL, exactly 1/16 of a US gallon) used elsewhere.
Historical origin. Cup was not the invention of a single named person; it developed through the process described above.
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.
Cup — sources
- US FDA — Reference Amounts Customarily Consumed — Uses the 240 mL rounded cup for nutrition labeling.
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 imperial fluid ounces are in 1 cup?
1 cup equals 8.326741846 imperial fluid ounces, using the exact defined conversion factor rather than an estimate.
How do I convert cup to imperial fluid ounce?
Multiply the cup value by 8.326741846. The converter above does this instantly to whatever precision you set.
How do I convert imperial fluid ounce back to cup?
Use the reverse factor: 1 imperial fluid ounce equals 0.1200949926 cups. You can also use the swap control in the converter above to flip the direction instantly.
What is a cup?
Cup (cup) measures volume. The US customary cup used in cooking is defined as exactly 240 milliliters (a rounded culinary standard, not the older 236.588 mL legal cup). It is classified as a US customary unit (culinary).
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.
Is the cup to imperial fluid ounce 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 cooking cup vs. legal us cup?
US recipes commonly round the cup to 240 mL for convenience, while the precise legal US cup (used to derive fluid ounces, pints, etc.) is 236.588 mL — a small but sometimes noticeable difference in precise baking.
Where is the cup still used today?
United States (recipes and cooking measurement)