Hong Life CalculatorsUnderstanding the volume converter — concept and principle
This converter changes a volume from one unit to another: liters, milliliters, cubic meters, cubic centimeters, cubic feet, cubic inches and US gallons. People use it for recipes and drink labels, aquarium and tank sizes, engine displacement, concrete or soil orders, moving boxes and fuel. Type a value, choose the unit you have and the unit you want, and the page also lists the same volume in every other unit.
How it is calculated
Every unit is stored as a fixed number of liters. The calculator first turns your value into liters, then divides by the size of the target unit:
- result = value × (liters per "from" unit) ÷ (liters per "to" unit)
- 1 mL = 1 cm³ = 0.001 L; 1 m³ = 1,000 L
- 1 in³ = 0.016387064 L; 1 ft³ = 28.316846592 L; 1 US gallon = 3.785411784 L
All of these factors are exact by definition, so the only rounding is in the display.
The principle
Volume is length cubed. A liter is defined as one cubic decimeter (a cube 10 cm on each side), so 1 L = 10 cm × 10 cm × 10 cm = 1,000 cm³. The same idea gives every cubic unit: because 1 inch is exactly 2.54 cm, 1 in³ = 2.54³ = 16.387064 cm³, and because 1 foot is 12 inches, 1 ft³ = 12³ = 1,728 in³. This is why volume factors look "odd": a small length factor gets multiplied by itself three times. The US gallon is defined as exactly 231 in³, which works out to 3.785411784 L.
Worked example
Default: 1 liter to milliliters.
- Convert to liters: 1 × 1 = 1 L.
- Divide by the size of a milliliter: 1 ÷ 0.001 = 1,000.
- Result: 1 L = 1,000 mL. The list also shows 0.001 m³, 0.0353146667 ft³, 61.02374409 in³ and 0.2641720524 US gallons.
How to read the result
Useful anchors: a standard drink can holds about 0.355 L, a wine bottle 0.75 L, a bathtub very roughly 150–300 L, and 1 m³ is a cube 1 m on each side (1,000 L, about 264 US gallons). If a result surprises you by a factor of 1,000, check whether you mixed up L and m³ or mL and L.
Common mistakes
- Using linear factors for cubic units: 1 m = 100 cm, but 1 m³ = 1,000,000 cm³.
- Confusing US and imperial gallons: an imperial gallon is 4.54609 L, about 20% larger.
- Treating volume as weight: 1 L of water is close to 1 kg, but 1 L of oil or flour is not.
Frequently asked questions
Is 1 mL exactly the same as 1 cm³?
Yes. Since 1964 the liter has been defined as exactly 1 dm³, so 1 mL equals exactly 1 cm³ (often written "cc").
How many liters are in a cubic foot?
Exactly 28.316846592 L, so about 28.3 L.
How many cubic inches are in a liter?
About 61.02 in³. This is why a 2.0 L engine is sometimes described as about 122 cubic inches.
Does the calculator use US or UK gallons?
US liquid gallons (3.785411784 L). For imperial gallons, divide liters by 4.54609.
Sources: BIPM, The International System of Units (SI Brochure), 9th edition, 2019 · NIST Special Publication 811 (2008), Guide for the Use of the International System of Units, Appendix B