Base filing deadline
Employees / standard filers31 MarchVerified
Extension
A request is required. Silence counts as approval — you don't need to wait for a confirmation.
Request online, via the canton's tax portal — Online (my.so.ch)
- Freeuntil 31 JulyVerified
- CHF 30until 30 NovemberVerified
Absolute maximum extension
30 NovemberVerified
If you miss it
- Formal noticeCHF 60Verified
- FineCHF 100Verified
The one deadline that's the same everywhere
A Pillar 3a contribution or pension-fund (BVG) buy-in counts for a tax year only if it's credited to your account by 31 December of that year — the date you initiate the payment doesn't count, only the date it lands.
Banks and 3a foundations often close their own booking cutoff a few days early (commonly ~24–27 December) so the payment posts in time — that's provider practice, not law, so don't wait until the 31st.
Sources & methodology
- View source →Last verified 2026-07-06
- When is the Solothurn tax return due?
- 31 March for employees / standard filers.
- Can I get a deadline extension in Solothurn?
- Yes — see the Extension section above for the exact process, cost, and channel.
- What happens if I miss the deadline in Solothurn?
- See the "If you miss it" section above for this canton's specific consequences.
- When's the deadline for a Pillar 3a contribution?
- 31 December, nationwide, for every canton — and the payment must be credited to your account by then, not just sent.