Barrels (oil) to gallons (US liquid) converter above calculates how many gallons (US liquid) are in 'X' barrels (oil) (where 'X' is the number of barrels (oil) to convert to gallons (US liquid)). In order to convert a value from barrels (oil) to gallons (US liquid) (from bbl to gal) simply type the number of bbl to be converted to gal and then click on the 'convert' button.