How to archive invoices properly

The Code of Obligations requires books, accounting records and business correspondence to be retained for ten years. The period starts at the end of the relevant financial year. Both issued and received invoices fall under this requirement.

The same retention period generally applies for VAT purposes to support returns and the right to deduct input tax. Certain documents relating to real estate must be kept for longer.

Electronic retention is permitted provided the documents remain readable for the entire period, cannot be altered without the change being detectable and can be accessed at any time. A stable, widely supported document format is perfectly suitable.

One point is often overlooked: keep the data used to produce the document as well as the final file. Regular exports of your invoices and customers protect you if you change tools.

One folder per financial year, one subfolder for issued invoices and another for received invoices, with filenames starting with the invoice number: this simple structure remains understandable ten years later, even to someone other than you.

A backup outside your computer, updated at least at every year-end closing, completes the setup. A single hard drive is not an archive.

Most fiduciaries work from a summary spreadsheet together with the supporting documents. A spreadsheet export containing number, date, customer, net amount, VAT and total avoids re-entering data and follow-up questions by email.