Volume Converter

Convert between litres, US and imperial gallons, cubic metres, millilitres, fluid ounces, cubic feet, and more — for liquids, gas, and dry volume.

Volume

L, gallons, m³, fl oz

From

Result

1000

1 L = 1000 mL

Popular conversions

What Is a Volume Converter?

A volume converter translates a three-dimensional measurement of capacity — litres to gallons, millilitres to fluid ounces, cubic metres to cubic feet — from one unit to another. Volume is length cubed, so its conversion factors are the cube of the length factors. The bigger trap, though, is that 'gallon', 'pint', and 'fluid ounce' mean different amounts in the US and the UK, so the country matters as much as the number.

This converter works from the litre and the cubic metre. A US gallon is 3.785 litres while an imperial (UK) gallon is 4.546 litres — about 20% larger — and a US fluid ounce differs from a UK fluid ounce too. The tool keeps these systems distinct so a recipe, a fuel figure, or a tank capacity converts to the amount you actually mean.

This is one category of the full Unit Converter — pair it with our percentage calculator or scientific calculator for related everyday maths.

How Volume Conversion Works

Volume factors are length factors cubed

If 1 ft = 0.3048 m, then 1 ft³ = 0.3048³ = 0.0283168 m³. Volume scales with the cube of the linear ratio, so errors compound fast.

Litre and cubic metre are the metric anchors

One litre is exactly 0.001 m³ (1 cubic decimetre); 1 m³ is 1,000 litres. Metric volume stays clean because it's powers of ten.

US and imperial gallons differ

A US gallon is 3.78541 L; an imperial gallon is 4.54609 L. That ~20% gap is why US and UK fuel-economy and recipe figures never match directly.

Dry vs liquid measure

The US also has separate dry units (dry pints, bushels) for grain and produce. This converter focuses on the common liquid and cubic units.

Core Volume Conversion Factors

Multiply to reach litres (or cubic metres) and divide to come back. Watch which gallon you mean.

US gallons → L

× 3.785412

One US liquid gallon is 3.785412 litres. The imperial gallon is larger at 4.54609 L.

Litres → US fl oz

× 33.814

One litre is 33.814 US fluid ounces. A US fl oz is 29.5735 mL.

ft³ → m³

× 0.0283168

One cubic foot is 0.3048³ = 0.0283168 m³. Used for gas, shipping, and HVAC volumes.

How to Use the Volume Converter

1
Enter the volume
Type the amount you want to convert — a recipe quantity, a fuel tank, a container capacity.
2
Pick the 'from' unit carefully
Choose the exact unit, and mind US vs imperial: a 'gallon' or 'fluid ounce' means different amounts in the two systems.
3
Pick the 'to' unit
Select your target unit, or swap the two with one tap to reverse direction.
4
Read all units at once
The all-units table converts your value into litres, both gallons, millilitres, fluid ounces, cubic metres, and more simultaneously.

Key Volume Concepts

Litre

A metric volume unit equal to exactly one cubic decimetre (0.001 m³). Not an SI base unit, but the everyday standard for liquids worldwide.

US vs imperial gallon

The US gallon (3.785 L) and imperial gallon (4.546 L) differ by about 20%. The UK and a few others use the imperial gallon; the US uses its own.

Cubic metre

The SI unit of volume — a cube one metre on each side, equal to 1,000 litres. Standard for gas, water utilities, and shipping.

Fluid ounce

A small liquid unit that also differs by system: a US fl oz is 29.57 mL, a UK fl oz is 28.41 mL. Recipes can go wrong if you use the wrong one.

Real-World Volume Conversions

⛽

Fuel at the pump

A 15 US-gallon tank is 56.8 L; 50 L is 13.2 US gallons (11 imperial). Drivers crossing between US, UK, and metric markets convert fuel constantly.

🍳

Recipe quantities

A US cup is 236.6 mL; a UK cup is 284 mL. Converting a recipe between systems — and the right cup — keeps proportions correct.

💧

Water bottles and jugs

A 1-gallon US jug is 3.79 L; a half-litre bottle is 16.9 US fl oz. Everyday hydration math across labels.

🚿

Water bills

Utilities bill in cubic metres or US gallons — 1 m³ is 264 US gallons. Converting clarifies a bill that quotes an unfamiliar unit.

📦

Shipping volume

Freight is quoted in cubic metres or cubic feet — 1 m³ is 35.3 ft³. Container and parcel pricing depends on getting this right.

🧪

Lab and medicine

Doses and reagents use millilitres and litres; 5 mL is one teaspoon. Precise small-volume conversion matters in clinical settings.

Best Practices for Volume Conversion

✓Always specify US or imperial. A 'gallon', 'pint', 'quart', or 'fluid ounce' is ambiguous without the system. The US and imperial versions differ by up to ~20%.
✓Cube the length factor for cubic units. 1 ft³ is 0.0283 m³, not 0.3048 m³. Cubic conversions need the linear ratio cubed, which trips many people up.
✓Use millilitres for small precise amounts. For medicine, lab work, and baking, millilitres avoid the ambiguity and rounding of teaspoons, fluid ounces, and cups.
✓Match the gallon to the region. US fuel economy uses the US gallon; UK figures use the imperial gallon. Converting mpg between them requires the right gallon.
✓Remember 1 L = 1 kg only for water. A litre of water weighs about 1 kg, but a litre of oil, fuel, or syrup does not — don't equate volume and mass for other liquids.

Common Volume Conversion Mistakes

Mixing US and imperial gallons

Treating a US gallon as imperial (or vice versa) introduces a ~20% error — enough to throw off fuel, recipe, and tank calculations.

Not cubing the length factor

Converting cubic feet to cubic metres with 0.3048 instead of 0.0283 inflates the answer ~35×. Cubic units cube the ratio.

Confusing US and UK fluid ounces

A US fl oz (29.57 mL) and UK fl oz (28.41 mL) differ by ~4%, which adds up across a multi-ingredient recipe.

Equating litres with kilograms

1 L = 1 kg holds only for water at 4 °C. For fuel, oil, or milk the mass differs, so don't swap volume and weight blindly.

Why Volume Conversion Matters

Volume is how liquids, gases, and bulk goods are bought, sold, dosed, and shipped — fuel, water, beverages, concrete, freight, and medicine all trade by volume. Because the US and imperial systems give different sizes to the same words, and because cubic conversions cube the error, a sloppy volume conversion can mean overpaying for fuel, ruining a recipe's ratios, or — in a clinical setting — getting a dose wrong.

The metric–imperial split is sharper here than almost anywhere else: a US gallon and an imperial gallon are both 'gallons' yet differ by a fifth. A converter that keeps the systems separate and handles the cubing automatically lets you trust the number whether you're filling a tank, scaling a recipe, or reading a freight quote.

Built for cooks, drivers, brewers, lab and medical staff, shippers, and anyone juggling litres, US gallons, and imperial gallons.

Linear unit factors follow the BIPM SI brochure, the NIST Guide to the SI, and ISO 80000. Currency rates load live from open.er-api.com; crypto prices from CoinGecko. See our methodology and editorial policy. Educational only — not certified for regulated trading, settlement, medical, or aerospace use.

Volume Converter FAQs

It depends on the gallon. A US liquid gallon is 3.78541 litres; an imperial (UK) gallon is 4.54609 litres — about 20% larger. Always specify which system you mean, because the same word 'gallon' refers to two different volumes.

Divide millilitres by 29.5735 for US fluid ounces, or by 28.4131 for UK fluid ounces. So 500 mL is 16.9 US fl oz or 17.6 UK fl oz. The US and imperial fluid ounce differ by about 4%, so the system matters.

A US gallon is 3.785 litres and an imperial gallon is 4.546 litres, so the imperial gallon is about 20% larger. This is why US and UK fuel-economy figures (miles per gallon) can't be compared directly without converting.

Multiply cubic feet by 0.0283168 to get cubic metres, because 0.3048³ = 0.0283168. So 100 ft³ = 2.83 m³. Cubic conversions use the cube of the length factor, not the length factor itself.

Only for water near 4 °C, where 1 litre weighs almost exactly 1 kilogram. For other liquids the density differs — a litre of petrol is about 0.74 kg, a litre of honey about 1.4 kg — so volume and mass are not interchangeable.

It uses exact unit definitions (US gallon = 3.785411784 L, imperial gallon = 4.54609 L, litre = 0.001 m³) and routes conversions through litres or cubic metres at full precision, so results are exact to your input precision.