Volume Converter
Exact volume conversions, US and UK measures, and an L × W × H box helper.
Type a volume in plain words — “20 L to gal”, “500 ml in fl oz”, “3 brass to m3”, “1 cbm to cft” — or use the boxes below.
Rounded · gal (US) = L ÷ 3.785411784
- Litre: exactly 1 dm³ (12th CGPM, 1964)
- Gallon (US): exactly 231 in³ = 3.785411784 L
Length × width × height
Work out the volume of a box, tank, room or pit. The sides can be in different units; the volume goes into the converter above.
1 L in every unit
Select a unit to convert to it. Values marked ≈ are rounded; all others are exact.
| Unit | Value | Copy |
|---|---|---|
| Metric | ||
| 1,000 | ||
| 1,000 | ||
| from | 1 | |
| 0.001 | ||
| US customary (liquid) | ||
| ≈ 33.8140227 | ||
| ≈ 2.113376419 | ||
| ≈ 1.056688209 | ||
| to | ≈ 0.2641720524 | |
| Imperial (UK) | ||
| ≈ 35.19507973 | ||
| ≈ 1.759753986 | ||
| ≈ 0.8798769932 | ||
| ≈ 0.2199692483 | ||
| Cubic (imperial & US) | ||
| ≈ 61.02374409 | ||
| ≈ 0.03531466672 | ||
| ≈ 0.001307950619 | ||
| Bulk & industry | ||
| ≈ 0.00628981077 | ||
| ≈ 0.02837759326 | ||
| ≈ 8.107131938 × 10⁻⁷ | ||
| Indian trade | ||
| ≈ 0.0003531466672 | ||
Convert a list of values
Up to 1,000 lines. Fractions (3/4), mixed numbers (1 1/2) and grouped digits (1,250) are fine.
| Value | Result |
|---|
About the Volume Converter
Convert volumes between millilitres, cubic centimetres (cc), litres and cubic metres (CBM), US and imperial gallons, quarts, pints and fluid ounces, cubic inches, feet and yards, the 42-gallon oil barrel, the US bushel, the acre-foot and the Indian trade unit “brass”. Type in either box and the other updates; every unit is listed in the table underneath with the formula used.
The arithmetic is exact. A US gallon is exactly 231 cubic inches = 3.785411784 L and an imperial gallon exactly 4.54609 L, so the results are exact and printed in full; only values that never end are rounded (marked ≈).
The Length × width × height helper works out the volume of a box, tank, room or pit from its sides, in any mix of units.
How to use it
- Type a volume in From and pick its unit, then pick the unit you want in To. You can also type in the To box to convert the other way.
- Or type a conversion in Quick convert, such as
20 L to gal,500 ml in fl oz,3 brass to m3or1 cbm to cft, and press Enter. - To start from measurements, fill in Length × width × height (for example 60 cm × 40 cm × 50 cm for a tank).
- Copy the result or a link, download the table of every unit as CSV, or convert a column of volumes with Convert a list.
Examples
20 L to gal (US)
≈ 5.283441047 gal (US)
20 L to gal (UK)
≈ 4.399384966 gal (UK)
1 CBM to cft
≈ 35.31466672 ft³
60 cm × 40 cm × 50 cm
120,000 cm³ = 120 L exactly
3 brass to m³
8.4950539776 m³ exactly (300 ft³)
1 bbl to L
158.987294928 L exactly (42 US gallons)
Common uses
- Fuel, water and paint quantities in litres or US and UK gallons.
- Water tanks, aquariums and pits from length × width × depth.
- Freight and shipping in CBM and cubic feet.
- Construction materials: sand and aggregate in brass, concrete in cubic yards or m³.
- Crude oil in barrels and irrigation or reservoir volumes in acre-feet.
Where the conversion factors come from
From NIST Handbook 44 (2026), Appendix C and the UK Weights and Measures Act 1985, Schedule 1:
- Litre = 1 dm³ = 0.001 m³ (12th CGPM, 1964); mL = cm³ (cc).
- US gallon = 231 in³ = 3.785411784 L; 1 gal = 4 qt = 8 pt = 128 US fl oz.
- Imperial gallon = 4.54609 L; 1 gal = 4 qt = 8 pt = 160 UK fl oz (1 UK fl oz = 1/20 pint).
- Cubic foot = 28.316846592 L; cubic yard = 27 ft³ = 0.764554857984 m³.
- Oil barrel = 42 US gallons, the customary barrel for crude oil and petroleum products (other “barrels” exist for beer, spirits and dry goods).
- US bushel = 2,150.42 in³ = 35.23907016688 L (struck measure).
- Acre-foot = 43,560 ft³ = 1,233.48183754752 m³.
Brass, CBM and cft
In western India sand, aggregate and excavation are often priced per brass, a trade convention of 100 cubic feet (2.8316846592 m³). It is not a legal unit of measurement, so contracts and bills should also give m³ or ft³. CBM is the shipping name for a cubic metre and cft for a cubic foot; 1 CBM ≈ 35.3147 cft.
Volume of a box or tank
Volume = length × width × height. With all three sides in the same unit the result is in that unit cubed (centimetres give cm³, which equal mL; millimetres are shown in mL). With mixed units each side is converted to metres first and the result is shown in litres (below 1 m³) or cubic metres. For a cylindrical tank use π × radius² × height instead — this helper handles boxes only.
Limitations
- Kitchen cups, tablespoons and teaspoons are not included, because their size differs by country and recipe.
- Volume cannot be turned into weight without the density of the material.
- The box helper handles rectangular shapes only.
- Inputs are limited to 60 characters; very large or very small results are shown in scientific notation.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How many litres are in a gallon?
It depends on the gallon: a US gallon is exactly 3.785411784 L and an imperial (UK) gallon exactly 4.54609 L. Fuel prices and recipes from the US use the US gallon; older UK figures use the imperial one.
How many cubic feet are in a cubic metre?
About 35.3147. A cubic foot is exactly 0.028316846592 m³, so 1 m³ = 35.31466672… ft³.
Is a UK fluid ounce the same as a US fluid ounce?
No, and it is the one imperial measure that is smaller than its US namesake: a UK fluid ounce is 28.4130625 mL and a US fluid ounce 29.5735295625 mL, about 4% more. The imperial pint, quart and gallon are about 20% larger than the US ones, because an imperial pint holds 20 fl oz and a US pint 16.
Is 1 mL the same as 1 cc?
Yes. A millilitre is defined as one cubic centimetre, so 150 cc = 150 mL.
How much is one brass?
100 cubic feet, which is 2.8316846592 m³. It is a trade convention, not a legal unit, so confirm the m³ figure with your supplier.
How many litres of water make 1 kg?
About one: a litre of water has a mass of about 1 kg near room temperature. Other liquids are lighter or heavier — a litre of cooking oil is less than 1 kg — so converting volume to weight needs the density.
How do I find the volume of a tank in litres?
Measure the inside length, width and depth and enter them under Length × width × height. For example 60 cm × 40 cm × 50 cm = 120,000 cm³ = 120 L.