Volume Converter

The SI unit of volume is the cubic metre. The litre (L), accepted for use with SI, is exactly one cubic decimetre (0.001 m³). US customary liquid volume is built from the fluid ounce (fl oz): 8 fl oz = 1 cup, 2 cups = 1 pint, 2 pints = 1 quart, 4 quarts = 1 US gallon (3.785 411 784 L exactly). Imperial (UK) units use the same names but different sizes: 1 imp gallon = 4.546 09 L. The US and imperial fluid ounce also differ: 29.574 mL vs 28.413 mL.

All conversions in this category are computed relative to a single base unit (Liter) using factors sourced from NIST Special Publication 811 and the BIPM SI Brochure. A shared reference unit keeps the conversion relationships consistent. Converting directly from the original measurement avoids the rounding differences that can accumulate when displayed intermediate results are entered again.

This calculator supports 18 units, including Liter, Milliliter, Cubic Meter, Cubic Centimeter, Cubic Millimeter. Choose the unit shown in your source measurement, then the unit needed for your result.

Units may have alternate spellings or abbreviations. You can search using these names too. Examples include Liter (l, also written as liters or litre), or Milliliter (ml, also written as milliliters or millilitre), or Cubic Meter (m3, also written as cubic meters or m³).

All volume conversions within the SI family are purely multiplicative: you multiply the source value by a fixed conversion factor derived from the ratio of the two unit definitions. Imperial-to-metric conversions use the exact defined equivalences (e.g., 1 inch = 25.4 mm exactly) rather than approximations.

When precision matters, avoid rounding intermediate calculations. The displayed factors and results are rounded for readability, usually to ten significant digits; very large or small values use scientific notation. Use the original measurement for each conversion and round the final answer to match the accuracy of that measurement.

Keep the unit alongside each volume value when you copy or share it. Check that the source and target units match your task. If two units have similar names, read their definitions before selecting one.

For a second check, use the worked example and formula on the conversion page. Start from your original value rather than a rounded result from another calculator. If you need to report a specific number of decimal places, round once at the end.