I know people who live fine with two kids on one phd salary (60k / year) or so. 120k CHF is definately enough to support a family. On 100k CHF you get already >7k CHF net, an apartment costs 2k - 2.5k if it is not in the city center and health insurance is 500 chf and food maybe 1k CHF more, so you can save 3k CHF every month. I run a tech recruitment firm in Zurich (coderfit.com), DM or email at [email protected] if you want to know more.