Amortization Schedule Generator
A full loan payoff table with yearly or per-payment views, plus extra-payment and biweekly comparisons showing exactly what each strategy saves.
The first payment is 86% interest
Every payment is the same size and what it is made of changes completely over the term. Interest is charged on the balance outstanding, so when the balance is largest the interest is too, and whatever is left goes on the loan. Taking $300,000 at 6.5% over 30 years, a payment of $1896.20:
| First payment | Amount | Share |
|---|---|---|
| interest | $1625.00 | 85.7% |
| principal | $271.20 | 14.3% |
The interest is nearly six times what you are actually repaying. It is not a fee or a charge — it is the month's rent on the money — but it does mean the loan barely moves for a long time.
And the crossover is much later than anyone guesses
The obvious question is when the two halves swap over. On this loan it is payment 233 of 360 — year 19.4. For more than half the term, most of every payment is interest.
| Through the term | Of the loan repaid |
|---|---|
| 25% | 10.4% |
| 50% | 27.4% |
| 75% | 55.1% |
Halfway through the term you have made half the payments and repaid 27.4% of the loan. That is not a penalty or a trick; it falls straight out of charging interest on a balance that starts high. But it means "I am halfway through my mortgage" and "I have paid off half my mortgage" are nowhere near the same sentence, and the gap is what surprises people selling early.
Over the whole term the interest comes to $382,633 on $300,000 borrowed — 128% of the amount, so the house costs $682,633 in total, 2.3 times its price.
Which is why early overpayments are worth so much
A pound of extra principal now removes every future interest charge that pound would have generated, for the whole remaining term. The same pound in the final year saves a few months of interest and nothing more:
| Extra per month | Term | Months saved | Interest saved |
|---|---|---|---|
| none | 30.0 years | 0 | — |
| $100 | 26.0 years | 48 | $60,995 |
| $250 | 21.8 years | 98 | $120,337 |
| $500 | 17.5 years | 150 | $179,759 |
It is the front-loading that makes this powerful, not any special treatment of extra money. Every additional pound lands against a balance that is still large, so it cancels interest that would have compounded for decades — which is why the advice is always "early" rather than "whenever you can".
A control worth having: run the same loan at 0% and there is no front-loading at all. Every payment is pure principal, and halfway through the term exactly 50% is repaid. So the whole effect on this page is the interest, not anything about how a schedule is shaped.
How to use
- Enter the loan amount, rate and term.
- Read the schedule by payment or by year.
- Add an extra payment to see the effect.
- Compare biweekly against monthly.
Frequently asked questions
What does an amortisation schedule show?
How each payment divides between interest and principal, and what the balance is after every one. It makes visible what a single monthly figure hides: that early payments barely touch the debt, and that the split reverses gradually over the term.
Why does the interest portion fall over time?
Because interest is charged on the outstanding balance, which shrinks with every payment. The payment stays level, so as the interest component falls the principal component necessarily rises — slowly at first, then with increasing speed toward the end.
How do biweekly payments save money?
By sneaking in an extra payment each year. Paying half the monthly amount every two weeks means 26 half-payments, which is 13 full payments rather than 12. On a 30-year mortgage this typically cuts four to five years off the term. The saving comes from the extra payment, not from the fortnightly timing.
Where is the best place to make an extra payment?
As early as possible. An extra payment in year one removes all the interest that principal would have accrued over the remaining decades; the same payment in year 25 saves only a few years of interest. The earlier, the larger the effect, by a wide margin.
Will my lender apply extra payments correctly?
Not always without being told. Some apply extra money to the next instalment rather than to principal, which does not reduce the interest at all. It is worth stating explicitly that an overpayment is for principal reduction, and checking the next statement to confirm it was.
Are there penalties for paying early?
Sometimes. Prepayment penalties are restricted in many places but not extinct, particularly on commercial and older loans. The loan documents will say, and it is worth checking before making a large overpayment or refinancing.
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