See how a 15-year fixed mortgage compares to a 30-year fixed — monthly payment, total interest, equity build-up, and the break-even point for refinancing.
Side-by-side monthly payment, total interest, and lifetime savings for the same loan amount at the same 6.5% rate. Click “Use this” on any 15-year or 30-year row to open the base mortgage calculator with that term pre-filled.
| Loan amount | 15-yr monthly | 15-yr total interest | 30-yr monthly | 30-yr total interest | Interest saved | Apply |
|---|---|---|---|---|---|---|
| $100,000 | $$871 | $$56,799 | $$632 | $$127,544 | $$70,745 | Use this → |
| $160,000 | $$1,394 | $$90,879 | $$1,011 | $$204,071 | $$113,192 | Use this → |
| $240,000 | $$2,091 | $$136,318 | $$1,517 | $$306,107 | $$169,788 | Use this → |
| $320,000 | $$2,788 | $$181,758 | $$2,023 | $$408,142 | $$226,385 | Use this → |
| $400,000 | $$3,484 | $$227,197 | $$2,528 | $$510,178 | $$282,981 | Use this → |
| $500,000 | $$4,356 | $$283,997 | $$3,160 | $$637,722 | $$353,726 | Use this → |
Assumes 6.5% rate for both terms. In practice, 15-year rates are typically 0.50–0.75 percentage points lower than 30-year rates, which would make savings even larger.
A 15-year fixed mortgage costs roughly 40%–50% more per month than a 30-year on the same loan amount, but you save 50%–65% in total interest and build equity twice as fast. For a $300K loan at 6.5%, the difference is $717 more per month to save $212,235 over the life of the loan — a $6.4% annualized return on the extra monthly payment — the loan rate, risk-free — which beats most investment-grade yields.
The trade-off isn’t always worth it: lenders want to see your monthly housing payment stay below 28% of gross income (front-end DTI). A 15-year only makes sense if your income supports the higher payment without crowding out retirement contributions, emergency savings, or other long-term investments.
Cross-checked against authoritative formulas (IRS, NIST, ACSM) and updated for 2025/2026 tax years and rates.
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