Should you trust the Zillow Mortgage Calculator?

You can trust the Zillow Mortgage Calculator as a mathematically accurate calculator for the inputs you give it, especially for estimating principal and interest. It’s useful for comparing scenarios like:

• how a bigger down payment changes your payment
• 15-year vs. 30-year loan terms
• rough monthly principal-and-interest costs

Where you should be cautious is in the assumptions beyond the loan math. Zillow’s estimates for property taxes, homeowners insurance, interest rates, PMI, and HOA fees are often general estimates, and they may not match your actual situation. Property taxes can also change after a sale, so historical tax data may not reflect what you’ll pay as the new owner.

Bottom line: use it for quick estimates and comparisons, but verify the numbers with actual lender quotes, local tax records, insurance quotes, and HOA information before making a buying decision.