Atmospheres (standard) to decibars conversion calculator shown above calculates how many decibars are in 'X' atmospheres (standard) (where 'X' is the number of atmospheres (standard) to convert to decibars). In order to convert a value from atmospheres (standard) to decibars (from atm to dbar) simply type the number of atm to be converted to dbar and then click on the 'convert' button.