Gallons (UK) to cubic decimeters converter above calculates how many cubic decimeters are in 'X' gallons (UK) (where 'X' is the number of gallons (UK) to convert to cubic decimeters). In order to convert a value from gallons (UK) to cubic decimeters (from gal to dm³) just type the number of gal to be converted to dm³ and then click on the 'convert' button.