How this conversion works
Every volume unit is defined as an exact amount of cubic meters. The liter is one cubic decimeter (0.001 m³). The US gallon is defined as 231 cubic inches, which works out to exactly 3.785411784 L, and the Imperial gallon is defined as exactly 4.54609 L.
US kitchen measures are fixed fractions of the US gallon: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces, and 1 fluid ounce = 2 tablespoons = 6 teaspoons.
Formula: result = value × (base units per source unit) ÷ (base units per target unit)
Where this conversion is used
- Converting recipes between cups, tablespoons and milliliters.
- Fuel, paint and liquid containers sold in US gallons, Imperial gallons or liters.
- Aquarium, pool and tank capacity.
- Medication and lab measurements in mL or fluid ounces.
Worked example: 5 US gallons to liters
- One US gallon is 3.785411784 L.
- 5 × 3.785411784 = 18.92705892 L.
- Rounded: about 18.93 L.
Unit definitions
| Unit | In cubic meters | Note |
|---|---|---|
| Liter (L) | 0.001 | |
| Milliliter (mL) | 0.000001 | |
| Cubic meter (m³) | 1 | |
| Cubic centimeter (cm³) | 0.000001 | |
| Gallon (US) (gal) | 0.0037854118 | 231 in³ exactly. |
| Quart (US) (qt) | 0.0009463529 | |
| Pint (US) (pt) | 0.0004731765 | |
| Cup (US) (cup) | 0.0002365882 | US customary cup = ½ US pint (≈ 236.59 mL). |
| Fluid ounce (US) (fl oz) | 0.0000295735 | |
| Tablespoon (US) (tbsp) | 0.0000147868 | |
| Teaspoon (US) (tsp) | 0.0000049289 | |
| Gallon (Imperial) (imp gal) | 0.00454609 | 4.54609 L exactly. |
| Pint (Imperial) (imp pt) | 0.0005682613 | |
| Fluid ounce (Imperial) (imp fl oz) | 0.0000284131 | |
| Cubic foot (ft³) | 0.0283168466 | |
| Cubic inch (in³) | 0.0000163871 | |
| Cubic yard (yd³) | 0.764554858 |
Liters to US gallons
| Liter (L) | Gallon (US) (gal) |
|---|---|
| 1 | 0.2642 |
| 2 | 0.5283 |
| 4 | 1.0567 |
| 5 | 1.3209 |
| 10 | 2.6417 |
| 20 | 5.2834 |
| 50 | 13.2086 |
| 100 | 26.4172 |
US cups to milliliters
| Cup (US) (cup) | Milliliter (mL) |
|---|---|
| 0.25 | 59.1471 |
| 0.333 | 78.7839 |
| 0.5 | 118.2941 |
| 0.75 | 177.4412 |
| 1 | 236.5882 |
| 2 | 473.1765 |
| 3 | 709.7647 |
| 4 | 946.3529 |
Things to watch for
- US and Imperial gallons, pints and fluid ounces are different sizes. An Imperial gallon is about 20% larger than a US gallon.
- The US “legal” nutrition-label cup (240 mL) differs slightly from the customary cup used here (≈ 236.59 mL).
Precision and sources
Results are calculated from the definitions above and rounded to 12 significant digits; the converter shows up to eight decimal places and the tables four. Reference: NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B. US gallon from the US Code of Federal Regulations; Imperial gallon from the UK Weights and Measures Act 1985.
Frequently asked questions
How many liters are in a gallon?
A US gallon is exactly 3.785411784 L. An Imperial (UK) gallon is exactly 4.54609 L.
How many cups are in a liter?
About 4.2268 US customary cups.
Is a milliliter the same as a cubic centimeter?
Yes. 1 mL = 1 cm³ exactly.