Amortization calculator with extra payments
Enter the loan amount, rate, term and any extra principal per month. On $250,000 at 6.5% for 30 years, the scheduled payment is $1,580.17; adding $100 a month pays the loan off 56 months early and saves about $58,860 in interest.
Inputs used by this calculator
Amortization Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Loan amount | 250,000 | 0 or greater | Supplies the loan amount quantity used by the published equation or result breakdown. |
| Annual interest rate (%) | 6.5 | 0 to 100 | Supplies the annual interest rate (%) quantity used by the published equation or result breakdown. |
| Loan term (years) | 30 | 0 to 100 | Supplies the loan term (years) quantity used by the published equation or result breakdown. |
| Extra principal per month | 100 | 0 or greater | Supplies the extra principal per month quantity used by the published equation or result breakdown. |
What an amortization schedule shows
An amortization schedule lists every payment with the interest, the principal and the remaining balance. The CFPB explains that more of each early payment goes to interest and that the principal balance falls slowly at first and faster near the end. Open the detailed schedule under the result to see every month.
How each month is calculated
Interest for the month is the balance times the monthly rate. The rest of the payment reduces the balance. Next month's interest is calculated on the lower balance, so the principal share grows over time.
interest = balance × annual rate ÷ 12principal = payment − interestnew balance = balance − principal − extraWhat extra payments do
Money added to principal lowers the balance immediately, so every later month charges less interest. On the $250,000 example, $100 extra each month shortens the loan by 56 months, and $500 extra saves about $163,500 in interest. The table compares several amounts.
Check how the lender applies extra money
Ask the lender to apply extra money to principal, not to the next scheduled payment, and check the statement. The CFPB notes that some loans carry a prepayment penalty; review the loan documents before paying ahead.
Extra payments versus refinancing
Extra payments keep the same rate and flexibility, while refinancing changes the rate and resets costs. The Refinance Calculator compares a new loan with the current one, including closing costs.
Scope of this model
The model assumes a fixed rate, monthly payments, and extra principal paid every month with no fee. Taxes, insurance and escrow are not part of the amortization; see the Mortgage Calculator for the full housing payment.
$250,000 at 6.5% for 30 years with extra principal
| Extra each month | Payoff time | Total interest | Interest saved |
|---|---|---|---|
| None | 30 yr 0 mo | $318,861 | — |
| $100 a month | 25 yr 4 mo | $260,001 | $58,860 |
| $200 a month | 22 yr 1 mo | $221,243 | $97,618 |
| $500 a month | 16 yr 3 mo | $155,345 | $163,516 |
Frequently asked questions
What is amortization?
Repaying a loan in scheduled payments that cover interest and reduce principal until the balance reaches zero.
Why is most of my early payment interest?
Interest is charged on the balance, which is largest at the start.
How much does $100 extra a month save?
On $250,000 at 6.5% for 30 years, about 56 months and $58,860 in interest.
Does paying extra lower my monthly payment?
No. It shortens the loan; the scheduled payment stays the same.
Can I be charged for paying early?
Some loans have prepayment penalties; check your documents.
Can I download the schedule?
Yes. Use Download CSV under More options to save every row.
Does this include taxes and insurance?
No. Use the Mortgage Calculator for the full monthly payment.
What to keep in mind
Assumes the lender applies the extra amount directly to principal every month with no fee. Confirm prepayment rules with the lender.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.