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