British thermal units (59 °F) to calories conversion calculator above calculates how many calories are in 'X' British thermal units (59 °F) (where 'X' is the number of British thermal units (59 °F) to convert to calories). In order to convert a value from British thermal units (59 °F) to calories type the number of British thermal units (59 °F) to be converted to cal and then click on the 'convert' button.