An imperial gallon is exactly 4.54609 liters.
Imperial gallons to Metric cups Converter — imp gal to metric cup
Convert Imperial gallon (imp gal) to Metric cup (metric cup) using the exact conversion factor (1 imperial gallon = 18.18436 metric cup). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Imperial gallons to Metric 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 metric cup is 250 milliliters.
Result = input x 0.00454609 / 0.00025.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Imperial gallons to Metric cups
Imperial gallon and Metric 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 gallon is typically associated with united Kingdom, Canada (some contexts), and other Commonwealth countries, while Metric cup is typically associated with australia, New Zealand, United Kingdom, Canada (recipes and cooking measurement).
Formula
metric cups = imperial gallons × 18.18436
This factor comes from each unit's defined relationship to the category's base unit: 1 imperial gallon equals 0.00454609 base units, and 1 metric cup equals 0.00025 base units, so dividing one by the other gives the direct imperial gallon-to-metric cup factor of 18.18436.
Simple example
1 imp gal × 18.18436 = 18.18436 metric cup
1 imperial gallon = 18.18436 metric cups.
Real-world example
10 imp gal × 18.18436 = 181.8436 metric cup
10 imperial gallons = 181.8436 metric cups.
Conversion table
| Imperial gallon (imp gal) | Metric cup (metric cup) |
|---|---|
| 1 imp gal | 18.18436 metric cup |
| 5 imp gal | 90.9218 metric cup |
| 10 imp gal | 181.8436 metric cup |
| 25 imp gal | 454.609 metric cup |
| 50 imp gal | 909.218 metric cup |
| 100 imp gal | 1,818.436 metric cup |
Reverse conversion: Metric cup to Imperial gallon
18.18436 metric cup × 0.05499231207 = 1 imp gal
18.18436 metric cups = 1 imperial gallons.
imperial gallons = metric cups × 0.0549923120748
For a page dedicated to this direction, see Metric cup to Imperial gallon.
Imperial gallon vs. Metric cup
| Aspect | Imperial gallon | Metric cup |
|---|---|---|
| Family | UK/imperial customary unit | Non-SI unit (culinary, metric countries) |
| Typical use | UK fuel and beverage measurement (historically; UK now primarily uses liters for retail) | Recipe and cooking measurement in metric-using English-speaking countries |
| Where it's used | United Kingdom, Canada (some contexts), and other Commonwealth countries | Australia, New Zealand, United Kingdom, Canada (recipes and cooking measurement) |
Understanding the Imperial gallon
Imperial gallon (imp gal) measures volume. The imperial gallon is defined as exactly 4.54609 liters, about 20% larger than the US gallon. It is classified as a UK/imperial customary unit.
Where it's used: United Kingdom, Canada (some contexts), and other Commonwealth countries
Imperial gallon vs. US gallon. Britain's 1824 Weights and Measures Act defined a new gallon based on 10 pounds of water, replacing the old wine gallon the US had already adopted — leaving the US (3.785 L) and imperial (4.546 L) gallons about 20% apart today.
Uses of the Imperial gallon today
- UK fuel and beverage measurement (historically; UK now primarily uses liters for retail)
- Commonwealth country liquid measurement in some contexts
History of the Imperial gallon
The imperial gallon was created by Britain's Weights and Measures Act of 1824, defined as the volume of 10 pounds of water, replacing several inconsistent older English gallon definitions (wine gallon, ale gallon, corn gallon) with one standard.
Historical origin. Imperial gallon was not the invention of a single named person; it developed through the process described above.
Understanding the Metric cup
Metric cup (metric cup) measures volume. The metric cup used in Australia, New Zealand, the UK, and Canada is defined as exactly 250 milliliters. It is classified as a Non-SI unit (culinary, metric countries).
Where it's used: Australia, New Zealand, United Kingdom, Canada (recipes and cooking measurement)
Metric cup vs. US cup. The metric cup (250 mL) is about 4% larger than the US cooking cup (240 mL) — small for most recipes, but worth checking when following a recipe from a different country.
Uses of the Metric cup today
- Recipe and cooking measurement in metric-using English-speaking countries
- Baking and portion measurement
History of the Metric cup
As Commonwealth countries metricated through the 20th century, cookbook publishers and standards bodies adopted a round 250 mL 'metric cup' so recipes could use a convenient, easily-scaled volume rather than the US's 240 mL or older imperial teacup conventions.
Historical origin. Metric cup was not the invention of a single named person; it developed through the process described above.
Imperial gallon — sources
- UK Weights and Measures Act 1824 — Establishes the imperial gallon definition.
Metric cup — sources
- National Measurement Institute (Australia) — Kitchen measures — Documents the 250 mL metric cup standard.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many metric cups are in 1 imperial gallon?
1 imperial gallon equals 18.18436 metric cups, using the exact defined conversion factor rather than an estimate.
How do I convert imperial gallon to metric cup?
Multiply the imperial gallon value by 18.18436. The converter above does this instantly to whatever precision you set.
How do I convert metric cup back to imperial gallon?
Use the reverse factor: 1 metric cup equals 0.0549923121 imperial gallons. You can also use the swap control in the converter above to flip the direction instantly.
What is a imperial gallon?
Imperial gallon (imp gal) measures volume. The imperial gallon is defined as exactly 4.54609 liters, about 20% larger than the US gallon. It is classified as a UK/imperial customary unit.
What is a metric cup?
Metric cup (metric cup) measures volume. The metric cup used in Australia, New Zealand, the UK, and Canada is defined as exactly 250 milliliters. It is classified as a Non-SI unit (culinary, metric countries).
Is the imperial gallon to metric cup conversion exact?
Yes. The metric cup used in Australia, New Zealand, the UK, and Canada is defined as exactly 250 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.
What is the difference between imperial gallon vs. us gallon?
Britain's 1824 Weights and Measures Act defined a new gallon based on 10 pounds of water, replacing the old wine gallon the US had already adopted — leaving the US (3.785 L) and imperial (4.546 L) gallons about 20% apart today.
Where is the imperial gallon still used today?
United Kingdom, Canada (some contexts), and other Commonwealth countries