The research allowance (Forschungszulage) can be applied for retroactively for projects going back to 2022 – up to four years. What matters is the four-year assessment deadline (Festsetzungsfrist) starting on 31.12. of the respective expense year. For expenses from 2022, this deadline expires on 31.12.2026.
Deadlines at a glance
| Expense year | Deadline ends |
|---|---|
| 2022 | 31.12.2026 – act soon! |
| 2023 | 31.12.2027 |
| 2024 | 31.12.2028 |
| 2025 | 31.12.2029 |
Why retroactive claims pay off
The BSFZ certificate is a basic assessment notice for the entire project and can be used for several financial years. With a single application you can therefore cover several past years – and then claim the allowance per financial year at the tax office. For companies that have been doing research for years without realising it, several annual amounts quickly add up.
Two points in time, two logics
Important for retroactive applications: what counts is the point at which the expense is incurred – that is, the year in which the costs arose. This point in time determines the funding rate and the cap. A retroactive application for 2022 is therefore calculated under the conditions in force at the time (25%, €4M assessment base, without the SME bonus and without the overhead flat rate), not under the improved figures from 2026 onward. The full overview is available under Amount & funding rates.
This must be distinguished from the assessment deadline: it is the outer limit up to which you can still claim an expense year for tax purposes at all. The BSFZ application itself is not bound to any deadline – you can file it before, during or after the project.
Completed and failed projects count too
Whether a project was successful is irrelevant to eligibility – what matters is that the R&D criteria were met. Failed approaches in particular are strong evidence of the technical risk. Even projects that have already been completed can therefore be activated retroactively, as long as the assessment deadline for the respective expense year is still running. How such a constellation pays off is shown by the example calculation.
What you should do now
- Identify R&D projects and their timeframes (git history, project management, invoices help with reconstruction).
- Roughly estimate the expenses per year – fastest with the flat-rate calculator.
- Prioritise years close to their deadline (2022!) and start the funding check.
Frequently asked questions about retroactive applications
How far back can I apply for the research allowance retroactively?
For expenses going back to 2022 – that is, up to four years. What matters is the four-year assessment deadline starting on 31.12. of the respective expense year.
Why is expense year 2022 urgent?
For expenses from 2022, the assessment deadline ends on 31.12.2026. An application filed in time is therefore time-critical if you still want to include 2022 costs.
Do I need prior approval for retroactive applications?
No. The research allowance can be applied for before, during or after the project; prior approval is not required. Completed or failed projects are eligible too.