How to Convert US gallons to Cubic metres (gal to m³)
Volume conversions help with baking from American recipes, comparing petrol prices quoted per gallon abroad with pump prices per litre here, and reading PUB water bills in cubic metres. This guide shows how to convert us gallons into cubic metres by hand, with examples and a quick-reference table.
The conversion
To convert us gallons to cubic metres, multiply the value by 0.00378541. To go the other way, divide by the same number (or multiply by 264.172176858). For a quick estimate, multiply by about 0.0038.
Cubic metres = us gallons × 0.00378541
Worked examples
- 3 gal = 0.011356 m³
- 12.5 gal = 0.047318 m³
- 75 gal = 0.283906 m³
US gallons to Cubic metres table
| US gallons | Cubic metres |
|---|---|
| 1 gal | 0.003785 m³ |
| 2 gal | 0.007571 m³ |
| 5 gal | 0.018927 m³ |
| 10 gal | 0.037854 m³ |
| 20 gal | 0.075708 m³ |
| 25 gal | 0.094635 m³ |
| 50 gal | 0.189271 m³ |
| 100 gal | 0.378541 m³ |
| 250 gal | 0.946353 m³ |
| 500 gal | 1.8927 m³ |
| 1,000 gal | 3.7854 m³ |
Common questions
Is gal to m³ exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Cubic metres to US gallons converter.
Mistakes to avoid
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Background
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
For any value, use the US gallons to Cubic metres Converter or browse all volume converters.
Run your own numbers: US gallons to Cubic metres Converter