Sharepoint formula EXP

Hi all,

Can someone spot the error with the below formula? It works in Excel, but i cannot get it to work in a sharepoint calculated column.

Thanks in advance!

=[Ref Ci strength]*EXP(-1*((0.693*(ROUNDDOWN([TODAY]-[Ref Ci date],1)))/75))

Ref Ci strength is a number column

Ref CI data is a date column

The returned data type is a number.