What this calculator does
Change any volume from one unit to another, from milliliters and liters to cups, gallons and cubic feet. Volume units come from two very different traditions. Metric units are tied to the meter. A liter is a cube 10 cm on each side, and a milliliter is a cubic centimeter.
US and British units grew out of older trade measures. The two countries ended up with gallons, pints and fluid ounces that share the same names but are different sizes. The British ones are called imperial.
This converter covers metric volumes, US kitchen and liquid measures, the main imperial measures, and cubic inches and feet. Enter a volume and pick the units. You get the result, the working through liters, and a table of all sixteen units.
Where it's used
Why this math matters outside the classroom:
- Soda bottles. A 2 L soda bottle holds about 8.45 US cups.
- Imperial pints. A UK pint of about 568 mL is about 1.2 US pints.
- Engine displacement. A 5.7 L engine has a displacement of about 348 cubic inches.
- Rainwater tanks. A 1 m³ storage tank holds 1,000 L, about 264 US gallons.
- Moving boxes. Movers comparing box sizes see that a 3 ft³ moving box holds about 85 L.
Grade level and standards: Grades 5–6; Common Core State Standards for Mathematics 5.MD.A.1, 6.RP.A.3.d. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Enter the volume. Zero and decimals are fine, but negative volumes aren't.
- Choose the unit you're converting from and the unit you want. Check whether a recipe or label means US or imperial measures.
- Read the result, or scan the table for all units at once.
What the inputs mean
- Volume
- The volume to convert, in the “From” unit.
- From
- The unit your number is in. Units marked US and imperial are different sizes.
- To
- The unit you want the answer in.
Formula and method
result = value × (from-unit in L) ÷ (to-unit in L) 1 US gallon = 231 in³ = 3.785411784 L 1 US cup = 1/16 US gal = 236.5882365 mL; 1 US fl oz = 1/128 US gal 1 US tbsp = 1/2 US fl oz; 1 US tsp = 1/3 tbsp 1 imperial gallon = 4.54609 L; 1 imperial pint = 1/8 gal; 1 imperial fl oz = 1/160 gal
The calculator stores each unit as its exact size in liters (L). To convert, it multiplies your value by the from-unit's size in liters. Then it divides by the to-unit's size in liters. in³ means cubic inches.
The US units all come from the gallon of 231 cubic inches. The inch is exactly 2.54 cm, so every US liquid measure has an exact metric value. The imperial gallon is set directly as 4.54609 liters.
The imperial gallon is about 20% larger than the US gallon. An imperial pint holds 20 imperial fluid ounces, while a US pint holds 16 US fluid ounces. The one surprise runs the other way. A single US fluid ounce (29.57 mL) holds a little more than an imperial one (28.41 mL).
Worked example
A recipe calls for 2 US cups of stock. How many milliliters is that?
- 1 US cup = 0.2365882365 L.
- 2 × 0.2365882365 L = 0.473176473 L.
- 0.473176473 L ÷ 0.001 = 473.176473 mL.
Result: 2 US cups is 473.176473 mL, which most cooks would round to about 475 mL.
Understanding the result
For cooking, rounding to the nearest 5 mL is usually fine. A US cup is about 237 mL, a tablespoon about 15 mL and a teaspoon about 5 mL.
When a measurement just says “gallon” or “pint”, the country it came from decides which one is meant. US recipes and products use US measures. Older British and some Canadian sources use imperial ones.
Assumptions and limitations
- US units are the US customary liquid measures based on the 231 in³ gallon.
- Imperial units use the exact definition of 4.54609 liters per gallon.
- US dry measures (the dry pint, dry quart, peck and bushel) aren't included.
- The metric cup (250 mL) and nutrition-label cup (240 mL) aren't offered.
- It converts volume only. Turning a volume into a weight needs the ingredient's density (how heavy it is for its size).
Frequently asked questions
How many milliliters are in a US cup?
Exactly 236.5882365 mL. Some nutrition labels round this to 240 mL. The metric cup used in several other countries is 250 mL.
Is a UK pint bigger than a US pint?
Yes. An imperial pint is about 568 mL, and a US liquid pint is about 473 mL. So the imperial pint is roughly 20% larger.
How many gallons are in a cubic foot?
About 7.48 US gallons. A cubic foot is 1,728 cubic inches, and a US gallon is 231 cubic inches. So the ratio is 1,728 ÷ 231 ≈ 7.4805.
Can I convert cups of flour to grams here?
No. Grams measure mass (weight). How much a cup of an ingredient weighs depends on its density and how tightly it's packed. Use a kitchen scale or a chart for that ingredient instead.
Is there a page for a single pair, such as mL to oz?
Yes. The kitchen and household pairs people convert most often have their own pages with a reference table. There are pages for milliliters to fluid ounces, cups to milliliters, liters to gallons and tablespoons to milliliters. There are also teaspoons to milliliters, quarts to liters, pints to milliliters and cups to ounces. And there are tablespoons to teaspoons, cubic feet to cubic meters and cubic feet to gallons. All of them use US customary measures.
How this calculator is checked
Method: US gallon = 231 in³ with 1 in = 2.54 cm (exact); imperial gallon = 4.54609 L (exact); US and imperial sub-units by their defined fractions. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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