I started working in CH while being 31 years old. I assume that I have a gap in terms of my payments for 1st and 2nd pillar.
1. How can check what my gap is? Do I need to write somewhere, or are there online services from government/canton?
2. How do I top up this gap?
3. Can I deduct this topping up in my tax declaration?
Contact them and tell them what amount you want to pay in
You can see from the link below that buy back missing AHV contributions, but only from five years prior. It is not possible to pay for older gaps.
Would be worthwhile, not finding out about the 5 year cap 10 years after coming in.
And the notification on your pillar 2 statement is quite clear.
For the second pillar, contact your job's pension fund.
Careful! The more one puts in the higher the tax percent on take out.
It was on my first pillar 2 statement here.
Pillar 2 is obvious, sure.
Well, I've heard about the "buying back" thing within my first 5 years here, but my inquiries ended with understanding that if I was working in EU before moving here I didn't have any AHV gaps to buy in. I don't know, maybe I misunderstood it due to language barrier, or maybe it was simply not possible due to EU laws.
OP, the term "gap" has many meanings. One might take a break without voluntary payment to AHV and zero contribution within a year makes you a gap in AHV years, where you need 40 years to get full 1st pillar pension. Now with 2nd pillar, the gap mean that the funds you have accumulated in your 2nd pillar will not provide you with retirement benefit giving you a lifestyle level matching your current one (living off your current salary). Of course people always start careers from lower salaries, so everyone has a gap at some point in their 2nd pillar as the previous contributions were much lower. Anyway, the minimum contribution (deduction from your salary) depends on your age. There are employers who pay more than the minimum, but most stick with the minimum I guess. In the end, the closer to the retirement the higher the % of your salary goes to 2nd pillar, plus usually your salary should be at the highest.
There's no time limit to top-up into your 2nd pillar, there's only amount limit. The more your earn the bigger pot you are allowed to have in your 2nd pillar, alas I don't really understand what's happening with 2nd pillar if someone riches the top of his career then decides to switch to some easy work paying peanuts. Most likely normal monthly deductions still have to be put into 2nd pillar but of course it won't be possible to top-up it as there would be much more money than a current salary would ever allow to build up.
Pillar 1 and Pillar 2 can be topped up but subject to guidelines.
Your employer should be able to confirm.