Do you have an agent? They should be able to pull up the most recent mf sales and help you out. Zillow, Realtor.com, and redfin usually have estimates on the properties. I wouldnt take them as fact but they're usually in the same ball park and can get you going.
Hope this helps!
Thank you Mr. Mike! I didn't have an agent, but i did use zillow, realtor.com , and redfin.