In my opinion 300k net. Live off 100k and invest 200k. That's 2.4 million per year for investments which is pretty decent. 100k is enough to live on and drive etc in Nairobi assuming you are single or have only one kid and a working spouse.

And the rent would be how much?

Deduct school fees and utilities from that. You'll be left with next to nothing if anything at all

You probably earn more, that's why. Comfortable is relative and you may already be used to luxuries not available to the common man. A single man will live very comfortably in Nairobi spending 100k per month on all expenses. The OP asked for a comfortable life, not luxurious life. 30k will get you a decent two bedroom apartment within a 20 km radius from CBD with secure parking. 70k is enough to maintain a basic 1500cc Premio, drink every Friday+nyama choma etc. 100k is a lot of money to spend for a bachelor or a man with a low maintenance employed girlfriend. However, I agree that the budget may exceed 100k if a kid comes into the picture because there will be need for at least 3 bedrooms (50k stand alone house in a gated estate), and normal expenses that come along with kids e.g live-n househelp, medical check-ups etc. So, 100k expenses may be a very tough call to live comfortably when raising a child. Say 150k if there is a kid. So, spend 150k and save/invest 150k.

90% of salary earning employees earn less than 100k married or otherwise.the trick is to adjust as the fortunes change.try to live within means and take that as the comfortable life in that season.some start down there but through hardwork and honesty later live a relatively comfortable life in a third world country standards