On: Google Fonts Analytics

[paxys]

I assumed 22 kb (compressed) font size. That's the average of the top 10 on their list. (Roboto is 35kb uncompressed for me, not 170kb).

[raphlinus → paxys]

35kb sounds like the basic (mostly latin-1) subset. The size will vary a fair amount depending on which subset is selected, etc. In any case, fonts will almost always be served compressed, with WOFF2 being the vast majority of requests.