Volume Converter

Litres, gallons, cups, and everything between

Volume conversion covers an unusually wide range of everyday situations — cooking, fuel, plumbing, shipping, and lab work all use different preferred units. This tool spans from millilitres and teaspoons up to cubic metres and UK gallons, so whether you're scaling a recipe, checking a fuel tank capacity, or converting a lab reagent volume, you can do it in one place without juggling separate calculators for cooking and for engineering.

US customary versus UK imperial volumes

One detail that catches people out: US and UK gallons are not the same size. A US gallon is defined as 3.78541 litres, while a UK (imperial) gallon is larger, at 4.54609 litres — about 20% bigger. The same applies to fluid ounces, pints, and quarts, though this tool focuses on the US customary versions for cups, teaspoons, tablespoons, and fluid ounces since those are the standard for most published recipes and product labels, while offering both US and UK gallon options given how often fuel and container capacities are compared across those two conventions.

Cooking-specific quirks

A US cup is standardised at 240 mL for conversion purposes (though a "legal" US cup used on nutrition labels is very slightly different, at 240 mL exactly, matching this tool). A UK or Australian "cup" measurement, common in some recipes, is closer to 250 mL — if you're converting a recipe and the result looks slightly off, check whether the original recipe specifies which cup standard it's using. For fine baking work, weighing dry ingredients in grams is generally more accurate than converting volume measurements, since a "cup of flour" can vary in actual mass depending on how it's packed.

Where this gets used

Home cooks adapting recipes between US, UK, and metric-only sources; brewers and winemakers scaling batch sizes; car owners checking fuel tank or oil capacity specs listed in litres against a US owner's manual in gallons; and students or lab technicians converting reagent volumes between millilitres and larger metric units are all common users of a volume converter. Because it's entirely client-side, it also works well as a quick reference while actively cooking, without needing to unlock a phone repeatedly to refresh a page.

Tips for reliable conversions

For recipes, round to practical kitchen measurements (nearest quarter-teaspoon or tablespoon) rather than using the raw decimal result. For fuel, engineering, or lab use, keep full decimal precision, and always double check whether a "gallon" or "ounce" value you're working from is specified as US or UK/imperial, since mixing the two silently introduces a 20% (gallon) or roughly 4% (fluid ounce) error — small differences that compound significantly in bulk calculations like fuel costing or industrial batch sizing.

When in doubt, check the source

If a recipe or specification doesn't state which measurement standard it uses, look for other context clues — the country of the publisher, the spelling conventions used elsewhere in the document, or accompanying metric figures — before assuming a default, since a wrong assumption here is one of the most common causes of a failed bake or a miscalculated fuel budget.