Loan payoff calculator
Calculator
The calculator needs JavaScript. The tables below give the same numbers for common cases.
How it is worked out
- Each month interest = balance × 0.005; the payment plus extra reduces the balance.
- Without extra: 197 months, interest $85,987.70. With extra: 154 months, interest $65,368.56.
| Inputs | Answer |
|---|---|
| Loan balance: 150000; Interest rate: 6; Regular monthly payment: 1200; Extra payment per month: 200 | With $200.00 extra a month the loan is paid off in 12 years 10 months instead of 16 years 5 months, saving $20,619.15 in interest. |
| Loan balance: 25000; Interest rate: 7.5; Regular monthly payment: 500; Extra payment per month: 100 | With $100.00 extra a month the loan is paid off in 4 years 1 months instead of 5 years 1 months, saving $1,018.22 in interest. |
| Loan balance: 300000; Interest rate: 5.5; Regular monthly payment: 2000; Extra payment per month: 500 | With $500.00 extra a month the loan is paid off in 14 years 7 months instead of 21 years 3 months, saving $72,171.66 in interest. |
How to use it
Extra payments go straight to the principal, so later interest shrinks. On a $150,000 balance at 6% with a $1,200 payment, adding $200 a month cuts the payoff time from 16 years 5 months to 12 years 10 months and saves about $20,600 in interest.
The calculator simulates every month with and without the extra amount and shows the time and interest saved. Check that your lender applies extra money to the principal and charges no prepayment penalty. These are estimates from the numbers you type, not financial advice or an offer; real products add fees and change rates.
Frequently asked questions
Do extra payments save interest?
Yes, because the balance on which interest is charged falls faster.
Should extra payments go to principal?
Yes; confirm that your lender applies them that way.
What if my payment is too low?
If it does not cover the interest the loan never pays off.
Method: standard arithmetic shown step by step; no outside data is used. Checked 2026-11-12.
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General information only. Results are plain arithmetic on the numbers you enter; check anything important (money, health, school work) against your own records or the official source.