How to charge late payment interest in Odoo

What Odoo does and doesn't do

• Payment terms set the due date. They don't add anything when a customer pays late.
• Payment follow-ups send reminders at levels you define. They don't calculate interest.
• No interest calculation. Odoo Community and Enterprise 17, 18, 19 and 20 have no standard way to charge interest on overdue or late-paid invoices. The usual workaround is a manual invoice with an interest product.

How statutory late payment interest works

Most European rules use the same pattern: a reference rate published twice a year plus a statutory margin, charged per day on the amount that is still open. Between businesses, the EU Late Payment Directive adds a fixed compensation of at least EUR 40 per late invoice.

• The rate changes on 1 January and 1 July. A late period that crosses one of those dates is charged at two rates.
• The open amount changes. A partial payment lowers it from the day after it is booked; a credit note lowers it from the due date.
• Business and consumer rates differ in several countries, and the fixed compensation applies to business customers only.
• Paid late still counts. A customer who paid 49 days late owes interest for those days, even though the invoice is now closed.
• Never twice. The same days and the same compensation must not be charged again next month.

This guide summarises the general pattern. Check your contracts and your national rules; it is not legal advice.

Charge it from Odoo with LateRate

1. Install LateRate on Odoo.sh or your own server (Odoo 19 or 20).
2. Choose your country rule in the Invoicing settings. Presets cover Sweden, Finland, Denmark, Norway, Germany and the EU directive.
3. Enter the current reference rate for the half-year.
4. Run the calculation up to today. Every late invoice, including invoices already paid late, gets a proposal with its periods, rates and compensation.
5. Review the proposals and create one draft interest invoice per customer, with the calculation attached as a PDF.

Good to know

• Nothing is posted or sent automatically. Posting and sending stay in your normal invoicing.
• Odoo Online can't install custom Python add-ons; use Odoo.sh or your own server.