ExpenseIn uses a third-party exchange rate and currency conversion service which updates to the current exchange rate every three hours from Currency Layer, a well-known and widely used currency source.
To allow users to enter their own exchange rate on their expense, turn on the setting for this in Advanced Settings in Admin.
If you wish you can also enter your own exchange rates which will be used in place of the real-time rates provided by our third-party software. Please see our Add custom exchange rates help article for more information.