How to change the amounts calculated on an invoice

Is there any way to change the calculations made by Invoice Ninja when creating an invoice? When trying to import a booking voucher (that is the official terminology that was given to us by the hotel owner, which describes a document that states that a client has reserved and paid for a room and contains the paid amount, the tax calculated from the paid amount and the price per stay excluding tax) into Invoice Ninja we get some differences because makes some rounding (up or down to make the price round to two decimals). The import process is to add the price per stay to the “Create Invoice Section” and then let Invoice Ninja do its magic to calculate the rest of the amounts (paid amount and tax). Although the differences are in cents of a euro, requires the hotel to issue a document (invoice + receipt) that has identical numbers with its voucher, otherwise the hotel owner needs to transfer the excess of money (cents) to . Is there any way to either change or add the rounding process of Invoice Ninja when creating an Invoice or at least arbitrarily add the numbers to the invoice so when it is created corresponds to the numbers the voucher has?

Best Regards,


You could create a custom invoice surcharge called ‘Adjustment’ on Settings > Invoice Settings.

Dear Hillel,

this is an excellent solution but at the same time one that involves manual input from the user and users might make errors. Is there a way to add a round() function make the Amount an integer?

Best Regards,

Panagiotis Mouratis

It may be possible by self hosting the app and modifying the code.

Would it be possible to point us to a set of files or a file where the calculations are performed?

You’re the man, Hillel!