Loan amortisation schedule
Every payment broken down. The interesting part is not the total, it is watching how long it takes before you are mostly paying off the debt.
Your figures
Result
- Total interest
- $77,666
- Total repaid
- $227,666
- Interest in year one
- $4,457
- Month when principal overtakes interest
- 84
- Month when half the debt is gone
- 220
- Number of payments
- 360
Month by month
| Month | Payment | Interest | Principal | Outstanding |
|---|---|---|---|---|
| 1 | $632.41 | $375.00 | $257.41 | $149,743 |
| 2 | $632.41 | $374.36 | $258.05 | $149,485 |
| 3 | $632.41 | $373.71 | $258.69 | $149,226 |
| 4 | $632.41 | $373.06 | $259.34 | $148,967 |
| 5 | $632.41 | $372.42 | $259.99 | $148,707 |
| 6 | $632.41 | $371.77 | $260.64 | $148,446 |
| 7 | $632.41 | $371.11 | $261.29 | $148,185 |
| 8 | $632.41 | $370.46 | $261.94 | $147,923 |
| 9 | $632.41 | $369.81 | $262.60 | $147,660 |
| 10 | $632.41 | $369.15 | $263.26 | $147,397 |
| 11 | $632.41 | $368.49 | $263.91 | $147,133 |
| 12 | $632.41 | $367.83 | $264.57 | $146,868 |
What we assume
- Level payments: the amount stays the same for the whole term.
- The rate entered is the nominal annual rate and the monthly rate is that divided by 12.
- A fixed rate is assumed. On a variable-rate loan the schedule is recalculated at each review.
- Fees, insurance and set-up costs are not included.
How it is calculated
Each month, interest is charged on what you still owe. Whatever is left of the payment reduces the debt:
interest = outstanding x monthly rate
principal = payment - interest
Since the outstanding balance falls every month, the interest share falls with it and the principal share grows. The payment never changes; its composition changes completely.
The two months worth finding
We flag the month when principal finally overtakes interest and the month when half the debt is gone. On a 30-year loan the second one lands around year 21, not year 15, and that single fact explains why overpaying early is worth so much more than overpaying late.
An example
On 150,000 at 3% over 30 years, the first payment is 375 interest and 257 principal. Principal only overtakes interest around month 150, and you are halfway through the debt around month 250 of 360.
Frequently asked questions
Why is so much of the early payment interest?
Because interest is charged on the outstanding balance, and at the start you owe almost everything. It is not a fee structure, it is arithmetic.
What happens to the schedule if I overpay?
The outstanding balance drops immediately, so every future interest charge is smaller. Use the early repayment calculator to see the effect.
Can I export it?
Yes, the CSV button gives you the whole table for a spreadsheet.
Keep calculating
All tools →- Loan payment calculatorWork out the monthly payment on a loan or mortgage and, above all, how much you will end up paying in interest.
- Early repayment: term or paymentOne lump sum, two ways to use it. Which saves more interest is not close, but the other one has its reasons.
- How much mortgage can I affordTwo things limit you: what you can pay each month and what you have saved. We tell you which one is binding, because that decides what to do about it.
Updated on 2026-08-26. Calculations run in your browser; nothing you type is sent to a server.