There is always a problem: what to take with, and what would be provided on place?
How it is with towels in saunas in Germany? Do you have to take a sauna towel with you? Or the towel is rented in price? Or maybe you don't need any towel inside sauna, and outside you can use your own towel, which don't have to be full size (for example, 80x60 would be enough)?
A towel is required. And it has to be large enough. You are supposed to sit or to lie on it. One towel can be enough. However, a second towel and/or a bathrobe can be useful too, when you are relaxing outside the sauna. In most of the saunas you can rent towels and bathrobes.
If 80x60 refer to centimeters, than it's not enough. You have to fit on the towel, as shown here:
However, sitting like this won't be accepted. You will then be kindly reminded to put your feet on the towel:
Most places have a policy requiring towels and also a rule with says "no sweat on the wood". You will need to have a towel big enough to cover the area to sit and for your feet. Just make sure that wherever you might drop sweat its covered by your towel. No one will measure your towel, just stick to this rule.
To answer the second part of the question: Saunas often provide towels and bathrobes (the latter might be mandatory in the bar/restaurant area, when there is one) but I have never seen them included in the entry price. Often, the sauna sells towels (as opposed to lending/renting them). In any case, it would always cost something on top of the regular price and most guests prefer to bring their own.
