Gallons (UK) to deciliters conversion calculator above calculates how many deciliters are in 'X' gallons (UK) (where 'X' is the number of gallons (UK) to convert to deciliters). In order to convert a value from gallons (UK) to deciliters (from gal to dL) simply type the number of gal to be converted to dL and then click on the 'convert' button.