As much as you want, or as little as you want. A single man can be homeless and dumpster diving, or doing coke and renting a penthouse. Comfort is very subjective, most presume a norm that just isn't justified (eg: references to 80k, or specific needs down to makes)
For a single person, I'd say the general thresholds are around 30-(50)-70k based on the US median city and you can scale that by your local COL. Below the 30 point you have failed hurdles that would make it uncomfortable (although I'd still question that, since it could result in community living and such which tends to be net positive, seen in places like Mexico). Over 70k results in nicer stuff, but it scales down very quickly at that point.
Having said that, it doesn't give you apples to apples. Living in the downtown core of San Fran is not the same as driving to work in Boston, or New Jersey to NY. The way money is spent is really different, with really different returns on QOL (comfort). It's less about what you spend on and more about what you get. Paying affordable rent but driving an hour to work because of traffic is not equivalent to transferring the cost to rent and walking to work. Some places can't pay enough to justify the prices (see China + smog, or Eastern Europe and crime, or many places + political security). There is no comfortable wage in these places (until you reach top 10% of local population).
I live in Vancouver (Canada), so I'm skewed towards best cities in the world. I pay ~1700 in rent for 800 sq ft... and that's on the low end of the area (~$3/sq ft average). But I don't own a car (walk to work, rent sometimes, car share the rest). It's one of the most expensive cities in the world to work/live in.
But the QOL transfer far outweighs price. I could cut my rent by 30-40% but I'd be driving to work everyday. It takes me ~50 min a day (my wife ~15 min), walking. Moving would move it up to a net of about 2h driving for both (back when we were doing it, it was about 2h20 min, since we ended up waiting for each other). It was about 3h using transit. Not only did we lose the stress of traffic and gain the exercise, we also saved about 20h/month. 20h! I consider the whole time saved since I should be doing at least that much cardio.
The "comfortable" wage in Vancouver is very high, but even with a lower wage ("uncomfortable", your QOL is better than most cities in the world.
My wife and I also spend about ~1400 on food. Probably more these days. There is no real reason to. We enjoy it, sure, and we eat well... but is it equivalent of the family making dinner together and eating together? Cost is not the same kind of enjoyment. Us, a couple, enjoy the date. The family is probably less stressed eating at home than packing up and going out. Singles could go out with friends, co-workers or romantic restaurants instead, for instance. But what is uncomfortable for one is beneficial for another.
So very different definitions of "comfortable".
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I guess what I'm trying to say is... no one needs 80k+ to be comfortable. 80k is "comfortable" for single parents with more than one kid. Yes, seriously. It's not
good that it is but it's well above the median. You can be secure there, although always at higher risk.
What you probably want to know are the minimum hurdles. Kids in households that are sub-40k will have a harder life (depending on your social systems, but certainly true in the states). Resource starvation is a real social problem.
You generally don't gain comfort or happiness from having a comfortable salary (again, minimum hurdle), but rather from social connections and meaningful efforts. So you can be pretty comfortable with surprisingly low wages because spending money may not be required for your particular needs... or require high wages to ever be comfortable (if you ever could be) because of social needs.
I think
this is a pretty good calculator. Seems pretty accurate for my area and family, at least.
Edit: It assumes you have a kid, so it might not be that great for a lot of folks here. Sorry.
I can't believe how much is taken up by medical insurance for you (US) guys. The total tax burden and relative housing seems kind of low but it is just my gut feeling.
The car costs - eventually you'll need a new car, so you could be "saving" for it now anyway. It's probably still fair and seems about right. (The better way to say it is that your current car is depreciating in value all the time, so it "costs" you regardless.)
Save. Save! Start as young as you can. And don't just save it in a piggy bank. Look into investing. Owning your own property is a good investment too, if you buy right. You don't need to live in it. Rent it out.
Saving is important but very different than investing.
Saving is for risk absorption (eg: variance in income or expenses). Most people should save between 3-12 months (depending on sources of income, variances in expenses, etc.) This is money that could be withdrawn quickly and without variance. Insurance is complementary to savings (lowering variance). The more insurance you carry, the lower your savings need to be. It is better to not insure the contents of your house if you have sufficient savings to replace the contents of your house, and so on.
Investments is about deferring consumption for increased consumption in the future. It's sub-optimal in more cases than you'd think. A normally overlooked cost comes from anything that would pay dividends, such as a degree. A typical example would be to spend more on your kids (money comes from somewhere!), vs leaving a legacy to them at the end. There is an entire other group that involves experiences now vs later. The marginal difference between them is actually very small for the amount deferred. Travel, for instance, because age makes it harder and less enjoyable, and has to be discounted for expected lifespan. Many are unable to travel; discount your future value by 20-25% (some 5-10% chance of it being 0, and the sliding scale for the rest) and suddenly it seems much less appealing.
Hence, it's not a good idea to mix "saving for travelling" and "investing for travelling" (retirement). The same applies for a great deal (majority?) of things.
But, seriously, save. And except for big investments, that appreciate in value (like property), avoid having a debt.
FWIW, property (land) only increases at inflation (on average) and property (buildings) depreciate in value. Using debt to finance them is only superior because of the amount of leverage available and relative stability, hence not having the debt called on you. That causes the property to rise at inflation and the debt to decrease at inflation, along with the income stream increasing at inflation for the life of the property (building).
Almost like buying bank stocks. Where the banking system is stable, anyway.
Debt is not inherently negative, but is situationally bad simply because needing debt means you do not have the equivalent in cash. For most people means that you bought something you couldn't afford (property included). It doesn't mean that it is sub-optimal to use debt. I'd mortgage myself as much as I could right this moment if someone was willing to do it. I just don't count as security for a loan, sadly.
