US vs UK Gallons, Cups and Ounces: Which One Do You Have?

A US gallon is 3.785 liters and a UK (imperial) gallon is 4.546 liters, about 20% more. In the kitchen, a US cup is about 236.6 mL, while the "metric cup" used in many recipes outside the US is 250 mL. Before converting any volume, figure out which system the original number comes from, because the same word can mean different amounts.

This guide helps you identify the unit you are dealing with, then convert it correctly.

Step 1: Work out which system you have

Clue	Likely system
US recipe site, American cookbook, US fuel prices	US customary
UK fuel economy in miles per gallon, older British recipes	Imperial (UK)
Australian, New Zealand, Canadian or South African recipe in cups	Often metric cup (250 mL)
Anything in mL, L or m³	Metric; no ambiguity

If you can't tell, look for other clues in the source: spelling ("color" vs "colour"), oven temperatures in °F or °C, and whether weights are in ounces or grams.

Step 2: Use the right factor

Gallons

• 1 US gallon = 3.785411784 L
• 1 UK gallon = 4.54609 L
• 1 UK gallon = 1.201 US gallons

A car with a 50-liter tank holds 13.21 US gallons but only 11.00 UK gallons. That gap is also why fuel economy in UK miles per gallon looks better than the same car's US figure: the UK gallon is larger.

Cups and spoons (US customary)

The US kitchen units nest neatly:

• 1 gallon = 16 cups
• 1 cup = 16 tablespoons = 236.59 mL
• 1 tablespoon = 3 teaspoons = 14.79 mL
• 1 teaspoon = 4.93 mL

So 2 liters of stock is 8.45 US cups, and 500 mL of milk is 2.11 cups.

Fluid ounces

A US fluid ounce is 29.57 mL. A 12 fl oz soda can holds 354.9 mL, and a 330 mL European can holds 11.16 US fl oz. The UK fluid ounce is slightly smaller, at about 28.4 mL; this converter uses the US definition.

Step 3: Decide whether you need volume at all

For baking, weight beats volume. A cup of flour can weigh noticeably more or less depending on how it was scooped, while 125 g is always 125 g. If a recipe gives both cups and grams, use the grams and a kitchen scale. For converting between ounces, pounds and grams of weight, use the Weight Converter.

Volume is the right choice for liquids, and for anything where small differences don't matter, like a soup or a marinade.

Beyond the kitchen

• Water tanks and pools: 1 m³ = 1,000 L = 264.17 US gallons.
• Shipping and storage: 1 cubic foot = 28.32 L.
• Engines: displacement in cubic inches converts at 16.387 mL per in³.
• Lab work: milliliters and centiliters; 1 cL = 10 mL.

How to use the Volume Converter

The Volume Converter includes metric, US customary and imperial units:

1. Type your amount in Value.
2. Choose From and To: milliliters, centiliters, liters, cubic meters, US teaspoons, tablespoons, fluid ounces, cups, pints, quarts, US gallons, UK gallons, cubic inches or cubic feet. The ⇄ button swaps them.
3. Read the result, or check the table showing your amount in every unit at once, handy for scaling a recipe up or down.

All the cooking units here (teaspoon through gallon, apart from the UK gallon) are US customary. For a metric cup, convert to milliliters and divide by 250. For a UK pint, which isn't in the list, use 568.26 mL.

Quick reference

Amount	Equivalent
1 US cup	236.59 mL
1 metric cup	250 mL
1 US pint	473.18 mL
1 US quart	946.35 mL
1 US gallon	3.785 L
1 UK gallon	4.546 L

FAQ

Why is a US pint smaller than a UK pint?

The US pint is 16 US fluid ounces (473 mL); the UK pint is 20 imperial fluid ounces (568 mL). Both systems kept the name "pint" while defining it differently.

How many liters are in a gallon of paint?

Paint sold in the US is measured in US gallons, so 3.785 L. Outside the US, check the label: the volume in liters is usually printed on the can.

Can I convert cups of flour to grams here?

Not directly. That needs the density of the ingredient, which varies. Convert cups to milliliters here, then use the ingredient's weight per milliliter from a trusted recipe source.

Convert cups, gallons, liters and more with the Volume Converter.