Invoices

Submitted invoices by 9 December 2025 at the latest, will probably be process and payed before the end of this year, as long as they meet the Leiden University guidelines and are approved in time by the budget holder.

From January 6, 2026, the processing of invoices will start in BAS InSite. Between December 9, 2025, and January 6, 2026, there will be a 'freeze' period. Invoices that come in during this time will be registered, but they will only be processed and paid in January 2026.

With this change, the use of SAP numbers will stop. This means that instead of the familiar SAP codes, project numbers and cost center numbers will be used to register costs and activities. More information about this change to new booking references will be shared later on this webpage.

• More information about Guidelines for submitting purchase invoices from third parties and freelancers
• More information about Guidelines for submitting purchase invoices

The contracted suppliers the university works with are kept informed about the relevant changes we are implementing and what these mean for them. For your own direct contacts, we have standardized information available that you can share. The key deadlines for 2025 are outlined in the letter.

Make sure to supplement the standardized information with specific details, and share the letter with the supplier as a PDF file. In November, suppliers with outstanding orders will receive an email from ASSC Finance regarding the revised deadlines for submitting invoices.