Volume Converter
Convert litres, millilitres, cubic metres, gallons, quarts, cups and spoons in one pass.
Awaiting input
Fill in the fields and press Calculate. Your result appears here and stays in view as you scroll.
The guide
Understanding the Volume Converter
Convert litres, millilitres, cubic metres, gallons, quarts, cups and spoons in one pass.
What each input means
The calculator asks for 3 pieces of information. Every field is validated before the maths runs, so an impossible value is refused rather than quietly producing a wrong answer.
| Input | What it asks for | Example |
|---|---|---|
| Value to convert | A number. | 2 |
| From | Choose one of 10 options. | Cups (US) |
| To | Choose one of 10 options. | Millilitres (ml) |
A worked example using the default inputs
With value to convert of 2, from of Cups (US), to of Millilitres (ml), the calculator returns 473.176 ml.
| Result line | Value |
|---|---|
| 2.000 US in ml | 473.176 ml |
| Conversion rate | 1 cup = 236.588 ml |
| Litres (L) | 0.47318 l |
| Cubic metres (m³) | 4.732e-4 m³ |
| Teaspoons (tsp) | 96.000 tsp |
| Tablespoons (tbsp) | 32.000 tbsp |
The same arithmetic runs whatever you type into the form above, so you can reproduce any figure by matching the inputs listed here.
How this is calculated
Convert to litres, then divide by the target unit’s litre factor. US liquid measures are used throughout.
Working values are kept at full precision and rounded only for display. Impossible dates, zero denominators, negative amounts where they make no sense, and out-of-range values are rejected before any result is shown.
How these conversions stay exact
Conversions are multiplications by fixed factors, so accuracy depends entirely on using the right factor and the right definition. Where a factor is defined exactly by international agreement it is used exactly; where a unit is a measurement convention, the agreed value is used and shown to a precision the input can support.
| Family | The approach | Where it is used |
|---|---|---|
| Exact defined factors | 1 inch = 25.4 mm, 1 pound = 0.45359237 kg | Length, weight |
| Base-unit chain | Convert into the SI base unit, then out to the target unit | Every converter in this section |
| Affine scales | F = C × 9/5 + 32; K = C + 273.15 | Temperature |
| US versus imperial | US gallon = 3.785411784 L; imperial gallon = 4.54609 L | Volume, fuel economy |
| Precision | Output rounded to the precision the input supports | Every converter in this section |
Temperature is the one family where the conversion is not a simple ratio. Because the scales start in different places, you multiply and then offset, which is why 20 °C is not twice as warm as 10 °C in any physical sense: it is 293 K against 283 K.
Recipe cups are the classic trap. A US customary cup is 236.6 mL, a metric cup is 250 mL and an Australian cup is 250 mL, so a cup of flour measured in different countries is a different weight before density is even considered.
Three worked examples from this section
Ten kilometres in miles
One mile is exactly 1.609344 km, so 10 ÷ 1.609344 = 6.2137 miles. For a quick check, multiply by 5 and divide by 8: 10 km is about 6.25 miles, which is close enough to sanity-check the number.
180 pounds in kilograms
One pound is exactly 0.45359237 kg, so 180 × 0.45359237 = 81.65 kg. In the other direction, a 70 kg adult is 70 ÷ 0.45359237 ≈ 154.3 lb.
- 180 lb
- 81.65 kg
- 70 kg
- 154.3 lb
- 1 stone
- 6.35 kg
100 °F in Celsius and kelvin
Subtract 32, multiply by 5 and divide by 9: (100 − 32) × 5 ÷ 9 = 37.8 °C. Adding 273.15 gives 310.9 K. The same steps reversed turn 37.0 °C into 98.6 °F.
Conversion factors and significant figures
Conversions use the exact defined factors where they exist (an inch is exactly 25.4 mm, a pound exactly 0.45359237 kg, a US gallon exactly 3.785411784 litres) and the internationally agreed values where measurement is involved.
- Results are shown to a precision that reflects the input. Multiplying a two-figure measurement by an exact factor still leaves you with a two-figure answer.
- US and imperial units differ: a US gallon is about 3.79 litres, an imperial gallon about 4.55. Choose the right one for the recipe or the vehicle.
- Temperature conversions are affine, not multiplicative; the offset is why doubling a Celsius temperature does not double a Fahrenheit one.
Sources and further reading
Reviewed 4 November 2026 · CalcFlow editorial
Common questions
Frequently asked
US or imperial gallons?+
US. An imperial gallon is about 4.546 L, roughly 20% larger. Check which one a recipe or fuel figure means.
Is a US cup 250 ml?+
No — a US customary cup is 236.6 ml. Metric recipes often round it to 250 ml, and Australian cups are 250 ml exactly.
Keep going
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