Mortgage Assumption Guide
Compare assuming an existing mortgage with taking a new market-rate loan.
Build a baseline, conservative case, and alternative
The calculator organizes assumptions. It does not replace a contract, tax determination, recommendation, or current market quote.
Start with source figures
Compare the assumed payment, cash needed for seller equity, fees, remaining term, and a same-balance market-rate loan.
- Confirm the loan is legally assumable.
- Request the current balance, rate, payment, and remaining term.
- Price any second loan or cash needed for the equity gap.
Run more than one scenario
Save the documented baseline, then change the assumption most likely to move. If a small change reverses the decision, gather better information or preserve more margin.
Verify before acting
Use the mortgage assumption calculator to create a comparable estimate, then reconcile important figures with the relevant statement, quote, contract, or official source.
Frequently asked questions
Does this guide predict the outcome?
No. It explains a deterministic comparison controlled by the values you enter.
What should I verify first?
Confirm the loan is legally assumable. Request the current balance, rate, payment, and remaining term. Price any second loan or cash needed for the equity gap.