I know xmr.to mentions that they don't charge a fee, but I'm sure they make a cut on the exchange rate some how. How does xmr.to make a profit? They have a fee their system if you exchange more, your fee is higher. What is this fee %?
XMR.TO admin here.
I do not know where you saw that XMR.TO does not charge a fee in general, this is not true and to the best of my knowledge we never made such statements. However it is true we do not charge anything on small orders. The reason is that, unlike all competitors, we are a Monero-specific service: we launched in 2015 for both building a business AND serving the Monero community, maximizing Monero's utility immediately rather than waiting for sufficient merchants acceptance in the future. We are also involved with Monero on an individual basis since inception and our interests align very much with those of the Monero community at large. As a result, we typically offer better prices than anyone else for everyday amounts. Currently the service is "free" for amounts up to 0.5 BTC.
We do charge something for larger orders (larger than 0.5 BTC). It is difficult to tell you how much, basically the percentage of the cut is proportional to the amount you exchange. This is why we specify in the FAQ that you need to enter the amount you want to exchange to find out about the specific rate we offer for this specific amount at that time.