See how extra monthly principal payments shrink your mortgage term and cut total interest.
Auto-updated · Verified daily against IRS, Fed & Treasury sources
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Payoff accelerated by 7.1 years
| Base Monthly Payment | $1,960 |
|---|---|
| New Monthly Payment (w/ extra) | $2,160 |
| Baseline Total Interest | $405,519 |
| New Total Interest | $293,735 |
| Interest Saved | $111,784 |
| Baseline Payoff | 30 years |
| New Payoff | 22y 11mo |
| Time Saved | 7.1 years |
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Each extra principal payment reduces the balance that future interest is calculated on, so all subsequent payments go more toward principal. Even small extras compound hugely over 30 years.
Compare your mortgage rate to expected investment return. If mortgage is 6.82% and index funds expect 7-8%, it's a wash. Paying extra gives historically reliable return; investing gives higher expected but variable return. For risk-averse, pay extra.
Most modern US mortgages do NOT have prepayment penalties (banned on QM loans by CFPB since 2014). Older loans or non-QM loans might. Check your promissory note.
Biweekly payments = 26 half-payments = 13 full monthly payments per year (1 extra). This typically shaves ~6 years off a 30-year mortgage and saves ~25% in total interest.
Every formula on this page traces to a federal agency, central bank, or peer-reviewed institution. We cite the rule-makers, not secondhand blogs.
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Result: ~$55k principal paid in 10 years vs $260k of payments — 21% principal ratio
Early-year mortgage payments are mostly interest. Year 1: ~85% interest / 15% principal. By year 10, it's about 60/40. Total principal built in first decade on a 30-yr loan is only 15–25% of the original balance. This surprises most homeowners.
Result: Pays off in year 22 vs year 30 — saves ~$85k interest
Shortening the term is mathematically better than extra principal at similar monthly totals because 15-yr rates price 0.25–0.50% lower. But it's inflexible — you can't skip the higher payment if cash flow tightens. Alternative: keep 30-yr term, apply $496/mo extra principal voluntarily.
Result: Paying off reduces monthly obligation by $1,150/mo — lowers retirement income needs
Math says keep the 5% mortgage and invest at 7%. Psychology and retirement planning say pay off — lower fixed obligations de-risk retirement income. Monte Carlo simulations show retirees with paid-off homes have 10–20% higher sustainable withdrawal rates. Many financial planners recommend paying off by retirement despite the spread.
Most conforming loans have none, but some non-QM and older subprime loans charge 1–3% prepayment penalties. Read your note.
Impact: A 2% penalty on $200k remaining = $4,000 surprise fee.
Keep 3–6 months expenses liquid and maintain 401(k) match at minimum. Mortgage payoff is a low-priority asset allocation vs emergency liquidity.
Impact: Forgoing 401(k) employer match to pay off mortgage = losing 25–100% historically reliable return (the match itself).
Selling $100k of stock with $40k capital gain = $6–$8k federal + state tax. Net you have $92k to pay off, not $100k. Model after-tax amounts.
Impact: Expecting to pay off $100k and finding you have $92k can leave $8k residual mortgage + tax surprise.
Calculations are for educational purposes only. Consult a qualified financial advisor for personalized advice.