Amortization Calculator
An amortization schedule shows the truth about a mortgage: early payments are mostly interest, late payments are mostly principal. This page shows the yearly split so you can see when the crossover happens.
Add an extra payment and every extra dollar goes straight to principal, which pulls the crossover forward and cuts the tail of the loan.
Results update as you type.
First 10 years
| Period | Interest | Principal | Balance |
|---|---|---|---|
| Year 1 | $20,572 | $7,756 | $312,244 |
| Year 2 | $20,052 | $8,276 | $303,968 |
| Year 3 | $19,498 | $8,830 | $295,138 |
| Year 4 | $18,907 | $9,421 | $285,716 |
| Year 5 | $18,276 | $10,052 | $275,664 |
| Year 6 | $17,602 | $10,726 | $264,939 |
| Year 7 | $16,884 | $11,444 | $253,495 |
| Year 8 | $16,118 | $12,210 | $241,284 |
| Year 9 | $15,300 | $13,028 | $228,256 |
| Year 10 | $14,427 | $13,901 | $214,356 |
How it works
First the scheduled payment comes from the standard amortizing formula: payment = B × r ÷ (1 − (1 + r)^−n), where B is the balance, r is the monthly rate (annual rate ÷ 12) and n is the number of payments left.
Then the loan is walked month by month. Interest for the month is balance × r; everything in the payment above that is principal; the balance falls by the principal part only. An extra payment is added to the principal line, so it never earns interest and the balance drops faster.
The table groups that loop by year. It assumes a fixed rate, payments applied on time, and no escrow, mortgage insurance or servicer fees — those sit outside the schedule.
Example
$320,000 balance · 6.5% rate · 25 years left · $200 extra a month
- Scheduled payment: $2,161 a month.
- First payment split: about $1,733 interest and $427 principal.
- Payoff in 20 yr 5 mo instead of 25 yr.
- Total interest $259,116, which is $69,083 less than staying on schedule.
Worked example using the figures above — an illustration, not financial advice. Your loan documents decide the real numbers.
Amortization Calculator FAQ
What is an amortization schedule?
A table that splits every payment between interest and principal and shows the balance left afterwards. On a $320,000 loan at 6.5% over 25 years, the first $2,161 payment pays $1,733 of interest and only $427 of principal.
When do most of my payment go to principal?
Once the balance falls below roughly half the original, the split flips. On that $320,000 loan at 6.5% with 25 years left it happens around month 173 — year 14. Any extra principal you pay moves that month earlier.
Does an extra payment change the amortization schedule?
Yes. Money applied to principal shrinks the balance immediately, so next month's interest is smaller and the whole schedule compresses. On that same loan, $200 a month cuts 4 years 7 months off the term and saves $69,083 in interest.
What is the difference between amortization and a payoff calculation?
A payoff calculation answers when the loan ends and what the interest costs. An amortization schedule answers what happens inside each individual payment. Same maths, different question.
Why is my real amortization schedule a few dollars different?
Servicers differ on interest accrual (30/360 versus actual/365), on payment posting dates, and on whether extra money sits in suspense before it hits principal. Match to the dollar only against your own servicer's method.
Is this schedule the same as the one on my statement?
Close, not identical. This one compounds monthly and applies every payment on time. Your servicer may accrue interest on an actual/365 basis, post payments on a different day, or hold partial payments in suspense — expect a few dollars of difference per month, not a different payoff year.
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Last updated October 4, 2026. Every figure is an estimate produced in your browser — see the methodology and its limits.