An imperial fluid ounce is 1/160 of an imperial gallon.
Imperial fluid ounces to Cups Converter — imp fl oz to cup
Convert Imperial fluid ounce (imp fl oz) to Cup (cup) using the exact conversion factor (1 imperial fluid ounce = 0.1200949926 cup). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Imperial fluid ounces to Cups 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 customary cup is 236.5882365 milliliters.
Result = input x 2.84130625e-5 / 0.0002365882365.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Imperial fluid ounces to Cups
Imperial fluid ounce and Cup 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 typically associated with united Kingdom (historically; less common in current UK retail than metric units), while Cup is typically associated with united States (recipes and cooking measurement).
Formula
cups = imperial fluid ounces × 0.12009499255
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 cup equals 0.0002365882365 base units, so dividing one by the other gives the direct imperial fluid ounce-to-cup factor of 0.12009499255.
Simple example
1 imp fl oz × 0.1200949926 = 0.1200949926 cup
1 imperial fluid ounce = 0.1200949926 cups.
Real-world example
10 imp fl oz × 0.1200949926 = 1.200949926 cup
10 imperial fluid ounces = 1.200949926 cups.
Conversion table
| Imperial fluid ounce (imp fl oz) | Cup (cup) |
|---|---|
| 1 imp fl oz | 0.1200949926 cup |
| 5 imp fl oz | 0.6004749628 cup |
| 10 imp fl oz | 1.200949926 cup |
| 25 imp fl oz | 3.002374814 cup |
| 50 imp fl oz | 6.004749628 cup |
| 100 imp fl oz | 12.00949926 cup |
Reverse conversion: Cup to Imperial fluid ounce
0.1200949926 cup × 8.326741846 = 1 imp fl oz
0.1200949926 cups = 1 imperial fluid ounces.
imperial fluid ounces = cups × 8.32674184629
For a page dedicated to this direction, see Cup to Imperial fluid ounce.
Imperial fluid ounce vs. Cup
| Aspect | Imperial fluid ounce | Cup |
|---|---|---|
| Family | UK/imperial customary unit | US customary unit (culinary) |
| Typical use | UK/Commonwealth beverage measurement in historical or specialized contexts | US recipe and cooking measurement |
| Where it's used | United Kingdom (historically; less common in current UK retail than metric units) | United States (recipes and cooking measurement) |
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 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.
Imperial fluid ounce — sources
- UK Weights and Measures Act 1824 — Basis for the imperial fluid ounce via the imperial gallon.
Cup — sources
- US FDA — Reference Amounts Customarily Consumed — Uses the 240 mL rounded cup for nutrition labeling.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many cups are in 1 imperial fluid ounce?
1 imperial fluid ounce equals 0.1200949926 cups, using the exact defined conversion factor rather than an estimate.
How do I convert imperial fluid ounce to cup?
Multiply the imperial fluid ounce value by 0.1200949926. The converter above does this instantly to whatever precision you set.
How do I convert cup back to imperial fluid ounce?
Use the reverse factor: 1 cup equals 8.326741846 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 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).
Is the imperial fluid ounce to cup conversion exact?
Yes. 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). 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)