Why "US" is in the name
A US gallon and a UK (Imperial) gallon are not the same size — the UK gallon is about 20% larger. The same is true of quarts, pints, and fluid ounces: every one of these unit names is shared between the two systems, but the actual volumes differ. This converter specifically uses the US customary definitions throughout, based on the US liquid gallon of exactly 231 cubic inches. If you're converting from a UK recipe or UK-specified capacity, the numbers here won't match — that's expected, not an error.
Exact conversion factors
| Unit | Equal to |
|---|---|
| 1 cubic meter (m³) | 1,000 liters |
| 1 cubic centimeter (cm³) | 1 milliliter (exactly) |
| 1 liter | 1,000 milliliters |
| 1 gallon (US) | 3.785411784 liters (exactly) |
| 1 quart (US) | ¼ gallon — 0.946352946 liters |
| 1 pint (US) | ⅛ gallon — 0.473176473 liters |
| 1 cup (US) | ⅝₆ gallon — 236.5882365 mL |
| 1 fluid ounce (US) | ⅓₂₈ gallon — 29.5735295625 mL |
| 1 cubic foot | 1,728 cubic inches (12³) |
| 1 cubic yard | 27 cubic feet |
These aren't rounded approximations — they're the exact legal definitions (the US gallon is defined as precisely 231 cubic inches, and an inch is defined as precisely 25.4mm, so every figure above follows directly with no accumulated rounding error).
Frequently asked questions
How many liters are in a US gallon?
Exactly 3.785411784 liters.
Is a US gallon the same as a UK gallon?
No — a UK (Imperial) gallon is about 20% larger than a US gallon (roughly 4.546 liters versus 3.785 liters). This converter uses US customary units throughout.
How many milliliters are in a cubic centimeter?
Exactly 1 — a milliliter and a cubic centimeter are the same volume by definition, just different names for it.