Cubic decameters to gallons (US liquid) conversion calculator above calculates how many gallons (US liquid) are in 'X' cubic decameters (where 'X' is the number of cubic decameters to convert to gallons (US liquid)). In order to convert a value from cubic decameters to gallons (US liquid) (from dam³ to gal) just type the number of dam³ to be converted to gal and then click on the 'convert' button.