This question might seem simple, so you might not like the answer. The truth is that you can put as much towards a mortgage as you can afford to! Some specialists say to stretch… and that building equity is worth the risk to your credit and life situation. Others say to cut back, buying less house then you think you can afford so that you will be alright no matter what your situation is.
I tend to agree with the latter.
As far as a figure goes, many say that 25% is an ideal amount of your income to spend on debts. This includes a car payment, a mortgage, and whatever other debts you may incur, like credit card payments. This also does not include closing costs, fees, or a down payment. So, as you can see, this leaves less then you probably thought.
Some say that it is ok to stretch this figure, especially if you plan on getting raises, a promotion, or something like that. 36% is considered about the max, but this is too often a little bit more of a stretch than people can handle.
What you should do is add up your debt, figure out how much extra you will have in that 25% figure, and then go for a house that is less then what you have to spend. This way, you will have money for other things, and if other things come up you can still afford to make the mortgage payment.