I highly recommend speaking with a high-quality loan specialist before house hunting. That way you really know what you can afford and will be comfortable with, in terms of a monthly payment.
But if you'd just like to try out a few scenarios first, check out these handy loan calculators that can help you a number of different ways.
Be aware, each home is different and may require special insurance or be in a higher property tax district, so these online tools should only be used for very general information.
If there's anything at all that I can do for you, here in Louisville Real Estate, or otherwise, please contact me. Thanks!