A US liquid gallon is exactly 3.785411784 liters.
Gallons to Cubic Decimeters Converter — gal to dm3
Convert Gallon (gal) to Cubic Decimeter (dm3) using the exact conversion factor (1 gallon = 3.785411784 cubic decimeter). See the formula, worked examples, conversion table, history, and common uses.
Gallons to Cubic Decimeters converter
Converter
Volume Converter
Convert metric, US customary, imperial, cooking, dry, and industrial volume units.
Context values
Some unit families need one extra value for a physically accurate result.
Cubic metric volume unit.
Result = input x 0.003785411784 / 0.001.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Gallons to Cubic Decimeters
Gallon and Cubic Decimeter appear side by side at fuel pumps and on beverage labels, since the US measures liquids in gallons while most of the world uses liters. Gallon is most often used for fuel pump and vehicle fuel-economy measurement in the us.
Formula
cubic decimeters = gallons × 3.785411784
This factor comes from each unit's defined relationship to the category's base unit: 1 gallon equals 0.003785411784 base units, and 1 cubic decimeter equals 0.001 base units, so dividing one by the other gives the direct gallon-to-cubic decimeter factor of 3.785411784.
Simple example
1 gal × 3.785411784 = 3.785411784 dm3
1 gallon = 3.785411784 cubic decimeters.
Real-world example
10 gal × 3.785411784 = 37.85411784 dm3
10 gallons = 37.85411784 cubic decimeters.
Conversion table
| Gallon (gal) | Cubic Decimeter (dm3) |
|---|---|
| 1 gal | 3.785411784 dm3 |
| 5 gal | 18.92705892 dm3 |
| 10 gal | 37.85411784 dm3 |
| 25 gal | 94.6352946 dm3 |
| 50 gal | 189.2705892 dm3 |
| 100 gal | 378.5411784 dm3 |
Reverse conversion: Cubic Decimeter to Gallon
3.785411784 dm3 × 0.2641720524 = 1 gal
3.785411784 cubic decimeters = 1 gallons.
gallons = cubic decimeters × 0.264172052358
For a page dedicated to this direction, see Cubic Decimeter to Gallon.
Understanding the Gallon
Gallon (gal) measures volume. The US liquid gallon is defined as exactly 231 cubic inches, equal to 3.785411784 liters. It is classified as a US customary unit.
Where it's used: United States (fuel, beverage, and liquid measurement)
US gallon vs. imperial gallon. The US liquid gallon (3.785411784 L) and the British imperial gallon (4.54609 L) are different units with the same name; always confirm which one a source is using.
Uses of the Gallon today
- Fuel pump and vehicle fuel-economy measurement in the US
- Beverage and liquid product packaging in the US
- Cooking and recipe measurement in US customary units
History of the Gallon
The US gallon descends from the English wine gallon of 231 cubic inches, a standard used for measuring wine in medieval and early modern England, which the American colonies inherited and retained even after England moved to a different imperial gallon in 1824.
England's 1824 Weights and Measures Act replaced the old wine gallon with a new imperial gallon (based on 10 pounds of water), but the US kept the older 231-cubic-inch definition — which is why the US gallon (3.785 L) and the imperial gallon (4.546 L) differ by about 20% today.
Historical origin. Gallon was not the invention of a single named person; it developed through the process described above.
Understanding the Cubic Decimeter (dm3)
Cubic metric volume unit.
Gallon — sources
- NIST Handbook 44, Appendix C — General tables of units of measurement, including the US gallon definition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many cubic decimeters are in 1 gallon?
1 gallon equals 3.785411784 cubic decimeters, using the exact defined conversion factor rather than an estimate.
How do I convert gallon to cubic decimeter?
Multiply the gallon value by 3.785411784. The converter above does this instantly to whatever precision you set.
How do I convert cubic decimeter back to gallon?
Use the reverse factor: 1 cubic decimeter equals 0.2641720524 gallons. You can also use the swap control in the converter above to flip the direction instantly.
What is a gallon?
Gallon (gal) measures volume. The US liquid gallon is defined as exactly 231 cubic inches, equal to 3.785411784 liters. It is classified as a US customary unit.
What is a cubic decimeter?
Cubic Decimeter (dm3) is a unit of volume.
Is the gallon to cubic decimeter conversion exact?
Yes. The US liquid gallon is defined as exactly 231 cubic inches, equal to 3.785411784 liters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between us gallon vs. imperial gallon?
The US liquid gallon (3.785411784 L) and the British imperial gallon (4.54609 L) are different units with the same name; always confirm which one a source is using.
Where is the gallon still used today?
United States (fuel, beverage, and liquid measurement)