Refinance Mortgage Payment Calculator
Use this refi mortgage payment calculator to estimate your new monthly payment, savings, break-even timeline, and long-term interest impact before you refinance.
How this refi mortgage payment calculator helps
Refinancing can lower your monthly mortgage payment, reduce total interest, or free up cash through a cash-out refinance. But there is a tradeoff: refinance costs, a possible term reset, and long-term interest effects. This calculator gives you a fast first pass so you can compare your current loan with a proposed new loan side by side.
Rather than focusing only on the new interest rate, this tool also estimates your break-even point and 5-year net impact. Those are often more useful decision metrics than rate alone.
What the calculator includes
- Current monthly principal + interest payment based on your remaining balance, rate, and term.
- New monthly principal + interest payment based on the refinance terms.
- Monthly savings (or increase) to show immediate cash flow impact.
- Break-even timeline based on closing costs and monthly savings.
- 5-year net impact to show short-to-medium-term financial effect.
- Lifetime interest difference for long-horizon comparison.
How refinance payment math works
Monthly mortgage payment formula
The calculator uses the standard amortization formula:
M = P × [r / (1 - (1 + r)-n)]
- M = monthly payment
- P = loan principal
- r = monthly interest rate (annual rate / 12)
- n = total number of monthly payments
If your new term is longer, your payment may fall even if your lifetime interest goes up. That is why a full comparison is essential.
When refinancing is usually worth considering
Strong refinance scenarios
- You can reduce your interest rate meaningfully and plan to stay in the home long enough to pass break-even.
- You want to move from an adjustable-rate mortgage to a fixed-rate loan for payment stability.
- You want to remove mortgage insurance after reaching enough equity (subject to lender rules).
- You need to shorten your loan term to build equity faster and reduce total interest paid.
Scenarios where caution is needed
- You are moving soon and may not recover closing costs.
- The new loan restarts a long term, reducing payment but increasing long-run interest.
- Your new APR is not much better once points and fees are included.
- You are using cash-out for discretionary spending rather than high-value debt restructuring.
How to use this calculator better
1) Compare at least three lender offers
Get Loan Estimates from multiple lenders. Small rate and fee differences can translate to thousands of dollars over time.
2) Evaluate both payment and total cost
A lower payment does not always mean a better deal. Check lifetime interest and your expected time in the home.
3) Track your break-even in months
If your break-even is 36 months but you expect to move in 24, refinancing may not make financial sense.
4) Review APR, not just note rate
APR includes some fees and gives a clearer apples-to-apples comparison of borrowing costs.
Example refinance comparison
Suppose you owe $300,000 at 6.75% with 25 years left. A lender offers 5.75% for 30 years with $6,000 in closing costs. Your payment may decrease, but the 30-year reset may increase total interest unless you make extra principal payments. This calculator lets you see those tradeoffs quickly before you commit.
Important notes
- This tool estimates principal and interest only.
- Property tax, homeowners insurance, HOA dues, and mortgage insurance are not included.
- Actual lender fees, escrow setup, appraisal costs, and prepaid items may differ.
- Consult a licensed mortgage professional for personalized advice.
Use this refi mortgage payment calculator as your starting point, then validate assumptions with official lender disclosures. Good refinance decisions are built on complete numbers, not just advertised rates.