Gallons to Cubic Meters
Type a value in either box to convert between gallons and cubic meters. The factor is 0.00378541.
| Gallons | Cubic Meters |
|---|---|
| 1 gal | 0.003785 m³ |
| 2 gal | 0.007571 m³ |
| 3 gal | 0.011356 m³ |
| 5 gal | 0.018927 m³ |
| 10 gal | 0.037854 m³ |
| 25 gal | 0.094635 m³ |
| 50 gal | 0.189271 m³ |
| 100 gal | 0.378541 m³ |
How to use
- Enter a value in the Gallons field.
- The Cubic Meters figure appears immediately — no button to press.
- Typing in the Cubic Meters field converts back to Gallons the same way.
- Use the reference table for the values that come up most often.
Gallons to Cubic Meters formula
The factor from gallons to cubic meters is 0.00378541178.
m³ = gal × 0.00378541178
Why this factor: the gallon and the cubic meter are both defined against the liter, so dividing one definition by the other gives 0.00378541178 directly. Both definitions are set out in full below.
To go the other way, divide by 0.00378541178 — or use the Cubic Meters to Gallons converter, which is the same calculation reversed.
Worked example
Start with 8 gal. Multiply by 0.00378541178 to get 0.030283 m³.
8 gal × 0.00378541178 = 0.030283 m³
The converter above does this for any value you type, in either direction.
What is a gallon?
A US liquid gallon is the standard large-volume unit in the United States.
Definition: Defined as exactly 231 cubic inches, which works out to exactly 3.785411784 liters.
Where it is used: Fuel sales, milk and beverage containers, and paint in the US.
Worth knowing: The imperial gallon used in the UK and Canada is about 20% larger, at 4.54609 L — so 'miles per gallon' figures are not comparable between the two.
What is a cubic meter?
A cubic meter is the SI unit of volume — the space in a one-meter cube.
Definition: Derived directly from the meter. Exactly 1,000 liters.
Where it is used: Freight and shipping volume, concrete and timber quantities, natural gas metering, and HVAC airflow.
Gallons vs Cubic Meters
The gallon is a US customary unit while the cubic meter is an SI unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many cubic meters are in a gallon?
One gallon equals 0.00378541178 cubic meters.
What is the formula to convert gallons to cubic meters?
Multiply the number of gallons by 0.00378541178. To reverse it, divide by 0.00378541178 instead.
How do I convert cubic meters back to gallons?
Divide by 0.00378541178, which is the same as multiplying by 264.172052.
How many cubic meters are in 10 gallons?
10 gal works out to 0.037854 m³.
Is there anything to watch out for with gallons?
The imperial gallon used in the UK and Canada is about 20% larger, at 4.54609 L — so 'miles per gallon' figures are not comparable between the two.
How is the gallon defined?
Defined as exactly 231 cubic inches, which works out to exactly 3.785411784 liters.