Asking for an extension and the tax interest

An extension and interest do not run the same way for every year of death. For a death in 2025 or earlier the ordinary deadline is eight months. For a death in 2026 the deadline for the return is twenty months. You do not ask for an extension with a loose note in the file. In the older cases, up to and including 2025, an extension of five months can be requested. That request must be in before the date on the letter from the Belastingdienst. After that date the request is too late and the eight-month deadline continues to run. Record the letter date before you send the request out.

The interest is a separate warning in those older cases. It can already run from eight months after the death, even if an extension has been granted. An extension of five months shifts the filing, not automatically the interest as well. Anyone who looks only at the new end date misses that difference. In the file the extension request and the interest stand side by side. Write the date on which the request was sent, and before which letter date that had to be. Keep the proof that the request was made in time. A task that only says an extension was requested, without those dates, cannot be checked later.

For a death in 2026 you do not invent a start date for the interest here. The Belastingdienst names a filing deadline of twenty months. How the interest works in that case is set out in the letter. Copy that explanation into the file, with the date of the letter, and do not add a rule of your own after it. The arrangement of five months' extension and of interest from eight months belongs to deaths up to and including 2025. It is not copied onto a death in 2026 just because the file sits on the same screen. If the year of death is wrong, the guidance is wrong.

Ervazo calculates no tax interest and grants no extension. The program keeps the task, the date of death and the documents you add. The inheritance tax indication uses the tables for 2026 and is not a calculation of interest. An amount on that screen says nothing about the interest that runs from a given moment. For a death up to and including 2025 you keep the letter date, the request for five months and the warning about eight months apart. For a death in 2026 you keep the deadline of twenty months apart, plus what the letter says about interest. The return itself goes outside the software.

An extension of five months, requested before the date on the letter, belongs to a death up to and including 2025. In those cases the interest can still run from eight months, even with an extension. For a death in 2026 the deadline of twenty months applies, and the letter explains the interest. No start date is invented alongside it here. This piece is a reading guide to those rules, not a calculation for a file. This is not legal advice and not tax advice. Whether an extension in a case was requested in time, and whether interest is running, you assess with the letter and with the Belastingdienst or an adviser.