The result of your conversion between Btu and femtojoule appears here
To convert between Btu and Femtojoule you have to do the following:
First divide 1055.0559 / 1.0e-15 = 1055055900000000000.
Then multiply the amount of Btu you want to convert to Femtojoule, use the chart below to guide you.
Symbol: Btu
No description
Symbol: fJ
No description