What are lenders ratios for morgages just for PITI?

I’m just looking for the lower ratio.. the one that just takes in to account PITI, not including other loans, because I don’t have any debt. I saw on a mortgage affordability calculator that it is 30 or 30/39. Is 30% normal or can you go higher? I don’t take on car, credit card, student [...] http://bit.ly/o3Z644