Hello, I apologize for being vague, but it depends. Where is your unit located in Waltham? As of today, there have been 22 condos sold in Waltham in the last 2 months, ranging from $160k to $535k. How many bedrooms and bathrooms do you have? Are there any special features to your condo that would set it apart from the rest of the condos on the market? Without additional information about your condo, it is tough to give you a sense of the value. For a hassle free comparative market analysis and market report, feel free to email me at email@example.com. Best of luck to you.