Can I get a good mortgage rate with a fico of 640 but low DTI?

You can get a good rate with that score, your DTI doesn't help the rate , the only facors for rate are score and loan to value. You need to speak with a local pro and look at both an FHA loan and conventional loan to see which works best for you. Also they can look at your credit to see if you can get your middle score up.

DTI does not affect your interest rate.. how much you put down, and your credit score will.. typically, the best pricing is for those with a 740 or above credit score.. But since rates are so low right now, then yes.. you can get a good rate, but you could get a better rate if your score were higher and/or your down payment were higher.. I'm a Broker here in Scottsdale AZ and I only lend in Arizona. If you or someone you know is looking for financing options, feel free to contact me or pass along my information. William J. Acres, Lender411's number ONE lender in Arizona. 480-287-5714 WilliamAcres.com