Volume Converter
Volume measurements are essential in cooking, medicine, commerce, and science, yet different regions and industries use vastly different units. The metric system uses millilitres for small quantities, litres for everyday volumes, and cubic metres for large quantities, all based on powers of 10 for easy conversion. The US customary system uses teaspoons, tablespoons, fluid ounces, cups, pints, quarts, and gallons with non-uniform conversion factors that are challenging to remember. Modern definitions are precise: 1 US fluid ounce equals exactly 29.5735 millilitres, 1 US cup equals exactly 236.588 millilitres, and 1 US gallon equals exactly 3,785.41178 millilitres. For engineering and construction, cubic inches and cubic feet are common in the United States, with 1 cubic foot equalling approximately 28.317 litres. Cooks following international recipes must convert between cups and millilitres, while scientists work almost exclusively in millilitres or litres. Shipping and industrial contexts use cubic metres for bulk quantities. This calculator displays fourteen common volume units simultaneously: metric units from millilitres to cubic metres, and US customary units from teaspoons to gallons, plus cubic inches and feet. Enter a value in any field and all others update instantly with NIST-defined precision.
NIST conversion factors
All conversions below use standard NIST-defined factors, with all units expressed relative to the millilitre.
| Unit | Symbol | Millilitres |
|---|---|---|
| Millilitre | mL | 1 |
| Centilitre | cL | 10 |
| Decilitre | dL | 100 |
| Litre | L | 1,000 |
| Cubic metre | m³ | 1,000,000 |
| US teaspoon | tsp | 4.92892 |
| US tablespoon | tbsp | 14.78676 |
| US fluid ounce | fl oz | 29.57353 |
| US cup | cup | 236.5882 |
| US pint | pt | 473.17647 |
| US quart | qt | 946.35295 |
| US gallon | gal | 3,785.41178 |
| Cubic inch | in³ | 16.38706 |
| Cubic foot | ft³ | 28,316.84659 |
Volume converter: frequently asked questions
What is the difference between US and metric volumes?
The metric system uses litres and millilitres as the base units for volume, with precise decimal relationships. The US customary system uses fluid ounces, cups, pints, quarts, and gallons with historical definitions. One US gallon equals approximately 3,785.41 millilitres, while one imperial gallon (UK) equals approximately 4,546.09 millilitres, making them quite different.
Why is a US cup different from a metric cup?
A US cup equals exactly 236.588 millilitres and is standardized for US cooking. A metric cup is defined as 250 millilitres. While similar, they are distinct, and recipes should specify which is intended. Most modern recipes use millilitres for precision.
What is a cubic metre used for?
A cubic metre (m³) is the SI unit for volume and equals 1,000 litres. It is used for measuring large quantities of liquids or gases, from swimming pools to industrial quantities of water or chemicals. One cubic metre is slightly more than 264 US gallons.
How precise are these conversions?
These are NIST-defined standard conversions: 1 US fluid ounce equals exactly 29.5735 millilitres, 1 US gallon equals exactly 3,785.41178 millilitres. All conversions shown are mathematically precise to two decimal places.
When would I use cubic inches or cubic feet?
Cubic inches and cubic feet are used in the United States for measuring volumes in engineering, construction, and industrial applications. One cubic foot equals approximately 28.3 litres, commonly used for air conditioning capacity or tank volumes in US contexts.
Official sources
- NIST Handbook 44: Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices.
- NIST Special Publication 330: The International System of Units.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.