Gallons (US liquid) to cubic meters conversion calculator shown above calculates how many cubic meters are in 'X' gallons (US liquid) (where 'X' is the number of gallons (US liquid) to convert to cubic meters). In order to convert a value from gallons (US liquid) to cubic meters (from gal to m³) just type the number of gal to be converted to m³ and then click on the 'convert' button.