Hold on, hold on. The amount highly depends on age and pension scheme.
The very bare minimum pillar 2 contribution is:
https://www.ahv-iv.ch/Portals/0/adam...tab_2020de.pdf
Employer and employee pay half of the contribution.
In addition the very bare minimum (a.k.a mandatory part) is just for part of sallary between CHF 24'885 and CHF 85’320
In the worst case the annual pillar 2 contribution is just CHF 4230.
The mandatory part is currently awarded with an interest of at least 1% https://www.bsv.admin.ch/bsv/de/home...tzinssatz.html
At pension age you can request (given some conditions) a pension of 6.8% (BVG conversion rate) of the accurred mandatory part amount. Other wise you will get the lump sum. https://www.bsv.admin.ch/bsv/de/home...lungssatz.html .
If your 20 years are from 25 to 44 you end up with around 140k at pension age (which you most likley must take as a lumnp sum).
If your 20 years are from 45 to 64you end up with around 220k at pension age.
That is the bare minimum. A particular pension plan might have better interest, interest might be lower in the follwing years, the mandatory contributions might change, the conversion rate might change, the conditions when you can request a pension instead of a lump sum might change, the condition when you can request a lump sum instead a pension might change, the pension age might change.
In addition to the bare minimum there is a so called non-mandatory part which covers your income above CHF 85’320, and in some cases also bellow CHF 24'885 (this is normally assumed to be covered by pillar 1, and is known as Koordinationsabzug/déduction de coordination). Just the bare minimum is very, very unusual.
Contribution for the non-mandatory is around the same as for the mandatory part (actual values depend on pension provider). Interest can be 0%. Conversion rate at pension age can be 0%. Depending on pension provider it is currently around 5 - 6 % https://www.pensionskassenvergleich....etze/index.php
In addition some employer pay a larger share of the contribution than the usual 50/50 split. And as said, nothing is fixed all of that can change in the future.
Comparing employer pension plans could make a huge difference. Employers with good pensions plans are for example Swisscom, Roche, or the City of Zurich. Things to check: Past performance (interest rates of mandatory and non-mandatory part, as well as funding ratio of a pension fund), contributions tables, employer/employee split of contribution, conversion rate of non-mandatory part, if there is a Koordinationsabzug/déduction de coordination.