Comparison
15-year vs 30-year refinance: comparing term tradeoffs
Compare estimated payments, interest, and simple payment break-even for 15-year versus 30-year refinance terms under the same illustrative loan assumptions — not market rate quotes.
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Choosing a refinance term changes more than the calendar length of the loan. Under the same assumed balance, rate, and closing costs, a shorter term usually means a higher monthly payment and less total interest, while a longer term usually lowers the payment and increases total interest. This page runs both paths through the same educational refinance model so you can inspect those tradeoffs with identical assumptions.
What differs
- New loan term length (180 vs 360 months) with the same assumed balance, new rate, and closing costs.
- Estimated monthly payment, total interest, and whether a simple payment break-even applies versus the stated current loan.
Illustrative scenario results
Illustrative shared assumptions (not market quotes): $320,000 balance, 6.5% current rate with 300 months remaining, 6.0% new rate, $4,000 closing costs.
| Option | Term | Est. new payment | Est. new interest | Payment vs current | Simple break-even |
|---|---|---|---|---|---|
| 15-year refinance | 180 months | $2,700.34 | $166,061.53 | -$539.68 | Not applicable |
| 30-year refinance | 360 months | $1,918.56 | $370,682.20 | $242.10 | 16.5 months (approx.) |
How to read these results
Under these illustrative assumptions, the 15-year path shows a higher estimated monthly payment and lower estimated interest than the 30-year path. The 30-year path shows a lower payment and more total interest over the full term. Payment break-even versus the stated current loan depends on whether the new payment is lower than the current payment; when it is not, break-even does not apply in this simple payment model. These outcomes follow from the term length difference and the fixed inputs — they are not a recommendation of either term.
When each approach may be useful to explore
These notes describe situations where comparing the paths can be informative. They are not recommendations.
- 15-year refinance path: You want to inspect how a shorter term changes estimated payment size and total interest under a fixed assumed rate — not as a recommendation.
- 30-year refinance path: You want to inspect how a longer term changes estimated payment size and total interest under the same assumed rate and costs.
Run your own numbers
This page uses fixed illustrative assumptions. For estimates based on inputs you control, open the Mortgage Refinance Calculator.
Assumptions
- All dollar amounts, rates, remaining term, and closing costs are illustrative assumptions entered for education — not quotes from a lender or a claim about current market rates.
- Both refinance options use the same assumed new rate, balance, and closing costs; only the new term length differs.
- Fixed-rate, fully amortizing loans with monthly payments; closing costs are treated as paid out of pocket.
- Taxes, insurance, PMI, points, and prepayment penalties are excluded unless folded into the closing-costs assumption.
Limitations
- Not a full economic refinance analysis; ignores tax effects, escrow, points, and lender overlays.
- Simple payment break-even is not a complete economic break-even.
- Assumed rates are not market quotes.
Methodology
- Each variant calls the site mortgage refinance engine (CALCULATOR-SPECS §1) with the shared base inputs and that variant’s new term in months.
- Monthly payment and interest use standard amortization (zero-rate shortcut when rate is 0%).
- Simple payment break-even = closing costs ÷ monthly payment savings when savings are greater than zero; otherwise not applicable.
Data provenance
Scenario inputs are illustrative assumptions defined in this dataset. Payment and interest figures are computed by the site’s mortgage refinance calculator engine — not scraped market statistics.
- Mortgage refinance methodology: docs/CALCULATOR-SPECS.md §1 (as of 2026-09-09)
- Scenario dataset: data/pseo/comparisons/15-vs-30-year-refinance.ts (as of 2026-09-09)
Do not treat assumed rates or balances as current market data. Re-run with your own inputs on the calculator page.