Barrels (US fluid) to cubic inches conversion calculator shown above calculates how many cubic inches are in 'X' barrels (US fluid) (where 'X' is the number of barrels (US fluid) to convert to cubic inches). In order to convert a value from barrels (US fluid) to cubic inches (from fl bl to cu in) simply type the number of fl bl to be converted to cu in and then click on the 'convert' button.