Loan Extra Payment Calculator
See exactly how much interest you save and how many months sooner you become debt-free by making extra monthly payments on your mortgage or loan.
All calculations run in your browser. No data is sent anywhere.
Your loan details
Comparison Summary
| Standard monthly payment | — |
|---|---|
| With extra payment | — |
| Original payoff term | — |
| New payoff term | — |
| Total interest (standard) | — |
| Total interest (with extra) | — |
| Interest saved | — |
| Paid off | — |
How Extra Payments Work
Why extra payments save so much
Every dollar of extra principal you pay today eliminates future interest charges on that dollar for the entire remaining loan term. Early in a loan (when the balance is high), each dollar saved prevents the most interest because it compounds over the most remaining years. Even a small, consistent extra payment — $50 or $100 per month — can save tens of thousands on a 30-year mortgage and cut years off the term.
Tips for making extra payments
- Specify "apply to principal" — make sure your lender knows the extra amount isn't prepaying next month's payment.
- Make it automatic — set up a slightly higher automatic payment each month so it happens without thinking.
- Annual lump sum — a tax refund or bonus applied once a year has the same compounding benefit as smaller monthly extra payments.
- Check for prepayment penalties — some loans (especially personal loans) charge a fee for paying off early. Verify your loan agreement first.
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Open calculator →FAQ
How does an extra payment reduce my loan?
Extra payments go directly toward your principal (when properly applied). A lower principal means less interest accrues each month, so more of each future payment goes toward principal — creating a compounding effect that accelerates payoff significantly.
How much can I save by paying $100 extra per month?
It depends on your balance, rate, and term. On a typical 30-year $300,000 mortgage at 7%, an extra $100/month saves roughly $36,000 in interest and shortens the loan by about 4 years. Use this calculator to get exact figures for your loan.
Should I make extra payments or invest the money?
Compare your after-tax loan interest rate to expected investment returns. Paying down debt is a guaranteed return equal to your interest rate. If your mortgage rate is 7% and you expect 8–10% stock returns, investing may win — but with more risk. Most advisors recommend maxing tax-advantaged accounts first, then consider extra loan payments if your rate is above ~5%.
Do I need to tell my lender the extra is for principal?
Yes — specify that extra amounts should be applied to principal, not your next scheduled payment. Many lenders default to treating extra money as a future-payment prepayment, which saves no interest. Use your lender's online portal "apply to principal" option, or write it on a check.