Introduction

Deadlines depend on how you file

German law distinguishes between self-filed returns and returns prepared by an advisor. After temporary pandemic relief, timelines have largely returned to the standard regime, with state tax offices publishing annual calendars that account for weekends and public holidays. :contentReference[oaicite:1]{index=1}

Voluntary vs. mandatory returns

If you are not required to file, you may still submit a voluntary return (Antragsveranlagung) to claim a refund. This has a generous 4-year window that always ends on 31 December of the fourth year after the tax year. :contentReference[oaicite:2]{index=2}

What happens if you miss a deadline

Late-filing surcharges are imposed by law and can be automatic after certain grace periods. Interest on under/overpayments accrues from the statutory interest start date at an annual rate currently set at 1.8% (0.15% per month). :contentReference[oaicite:3]{index=3}

1) Key filing dates (Assessment Years 2024–2026)

If a deadline falls on a weekend/holiday, the due date moves to the next working day; state tax office pages publish the exact operative dates each year. :contentReference[oaicite:7]{index=7}

2) Voluntary filing (Antragsveranlagung)

If you are not obliged to file, you can still submit a return within four years after the tax year—deadline is always 31 December of the fourth year (e.g., for 2025, until 31 December 2029). :contentReference[oaicite:8]{index=8}

This 4-year window is a practical rule publicized by authorities and guidance portals; special cases around limitation periods can exist—see professional commentary if edge cases apply. :contentReference[oaicite:9]{index=9}

3) Late filing surcharges & interest

• Late-filing surcharge (Verspätungszuschlag): Generally 0.25% of the assessed tax per started month, with a minimum €25 per month and a cap of €25,000. Rules are set in §152 AO and applied via your assessment notice. :contentReference[oaicite:10]{index=10}
• Interest on under/overpayments: Statutory rate currently 0.15% per month (1.8% p.a.) under §233a AO (revised 2022; next evaluation due by 1 Jan 2026). :contentReference[oaicite:11]{index=11}
• Automatic imposition: For returns filed well past the legal deadline, surcharges can be mandatory; even modest delays can trigger a surcharge at the tax office’s discretion. :contentReference[oaicite:12]{index=12}

4) ELSTER & electronic filing rules

• ELSTER portal: “Mein ELSTER” is the official online portal to prepare and submit returns electronically. One-time registration required. :contentReference[oaicite:13]{index=13}
• Mandatory e-filing for business/professional income: If you have Gewinneinkünfte (self-employment, trade, farming/forestry), the income tax return must be filed electronically; paper returns can be rejected unless a hardship exemption is granted. :contentReference[oaicite:14]{index=14}
• Employees/retirees: May typically still file on paper, though e-filing is encouraged. :contentReference[oaicite:15]{index=15}
• Software parity: Whether you use tax software or ELSTER directly does not change the legal deadline. :contentReference[oaicite:16]{index=16}

6) Compliance checklist & useful links

• Confirm if you are obligated to file; if not, consider a voluntary return within 4 years.
• Note the self-filed vs. advisor-filed deadlines for your specific assessment year.
• Use Mein ELSTER and keep certificates ready for e-filing; request hardship relief for paper only if truly necessary.
• File on time to avoid late-filing surcharges and interest.

• State deadlines (Baden-Württemberg): self-filed/advised dates incl. 2025/2026. :contentReference[oaicite:21]{index=21}
• General rule 31 July / advisor end-Feb (PwC summary). :contentReference[oaicite:22]{index=22}
• Voluntary filing window (4 years). :contentReference[oaicite:23]{index=23}
• Late-filing surcharge (§152 AO) & examples. :contentReference[oaicite:24]{index=24}
• Interest under §233a AO: 0.15%/month (1.8% p.a.). :contentReference[oaicite:25]{index=25}
• ELSTER portal & mandatory e-filing for Gewinneinkünfte; hardship exception. :contentReference[oaicite:26]{index=26}

7) FAQ