Imperial Gallons to Metric Cups (gal (UK) to cup)

1 imperial gallon equals 18.18436 metric cups exactly.

1 imperial gallon = 18.18436 metric cups

How to convert imperial gallons to metric cups

To convert imperial gallons to metric cups, multiply the number of imperial gallons by 18.18436. This factor is exact. To go the other way, multiply metric cups by 0.05499231207 (rounded).

metric cups = imperial gallons × 18.18436

Example: 10 imperial gallons = 181.8436 metric cups.

Pints, quarts, gallons and fluid ounces differ between the US and the UK. Units are labeled 'US' or 'imperial' to avoid confusion.

About these units

Imperial Gallon (gal (UK))

Imperial (British)Current unit

Exactly 4.54609 liters, the volume of 10 pounds of water. Used for fuel economy in the UK (miles per gallon) and historically across the Commonwealth.

Britain unified its confusing gallons by act of Parliament in 1824. Before then, the country used separate ones for wine at 231 cubic inches, ale at 282 and corn at about 268.8. The 1824 reform replaced them with the imperial gallon, defined as the volume of ten pounds of distilled water, calculated at 277.274 cubic inches. A new definition in 1889 slightly changed that, and after the liter was restored to exactly a cubic decimeter in 1964, Canada and then the UK in 1976 adopted the exact value of 4.54609 liters.

Because the United States kept the 231-cubic-inch wine gallon, an imperial gallon is about 20 percent larger than a US gallon. That explains why a car rated at 40 miles per gallon in Britain is less impressive in American terms, since it comes to roughly 33 US miles per gallon. Ireland dropped the gallon as a primary trade unit at the end of 1993 and the UK at the end of September 1995, but it lives on in British fuel-economy figures and older recipes.

1 imperial gallon = 4.54609 liters (exactly).

Sources: Wikipedia: Gallon; UK Weights and Measures Act 1985, Schedule 1

Metric Cup (cup)

Cooking & barCurrent unit

Exactly 250 mL. The cup used in Australia, New Zealand and most Commonwealth recipes.

A metric cup is a cup tamed by decimal thinking. Australia, Canada, New Zealand and some other former British colonies that metricated use a round 250 milliliters, exactly a quarter of a liter. Canada's older cup had been eight imperial fluid ounces, about 227.3 mL, so the metric version is noticeably larger, and Canadian recipes now usually use the 250 mL cup.

The metric cup is not an SI unit, only a practical convention, and it differs from the US cups in useful ways. It is about 6 percent larger than the US customary cup at 236.6 mL and about 4 percent larger than the 240 mL US label cup. Its arithmetic is simple: four cups make a liter, and a cup holds 50 metric teaspoons or 16 and two thirds tablespoons of 15 mL. Many recipes outside the US skip cups entirely and give dry ingredients in grams, because volume is a rough proxy for flour.

1 metric cup = 0.25 liters (exactly).

Sources: Wikipedia: Metric cup; Wikipedia: Cup (unit)

Related conversions

See all volume units.