Liter-atmosphere to British thermal units (IT) conversion calculator shown above calculates how many British thermal units (IT) are in 'X' liter-atmosphere (where 'X' is the number of liter-atmosphere to convert to British thermal units (IT)). In order to convert a value from liter-atmosphere to British thermal units (IT) (from L atm to BTU) simply type the number of L atm to be converted to BTU and then click on the 'convert' button.