Loan Amortization Calculator
Generate a full payment schedule for any loan and see exactly how each payment splits between interest and principal.
Your details
Extra payments
This calculator runs entirely on your device. Nothing you enter is uploaded, stored, or sold. How this works
Monthly payment
$1,580.17
30 yrs to pay off
Includes your inputs, the full breakdown, and every row of the table.
Total interest
$318,861
Total paid
$568,861
First payment is
86%
Interest
Interest saved
—
- Loan amount
- $250,000
- Rate
- 6.50%
- Scheduled payment
- $1,580.17
- Interest in the first payment
- $1,354.17
- Principal in the first payment
- $226.00
- Halfway paid off at
- 21 yrs 5 mo
- Total interest
- $318,861
- Total paid
- $568,861
| Month | Payment | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | $1,580.17 | $1,354.17 | $226.00 | $249,774.00 |
| 2 | $1,580.17 | $1,352.94 | $227.23 | $249,546.77 |
| 3 | $1,580.17 | $1,351.71 | $228.46 | $249,318.31 |
| 4 | $1,580.17 | $1,350.47 | $229.70 | $249,088.61 |
| 5 | $1,580.17 | $1,349.23 | $230.94 | $248,857.67 |
| 6 | $1,580.17 | $1,347.98 | $232.19 | $248,625.48 |
| 7 | $1,580.17 | $1,346.72 | $233.45 | $248,392.04 |
| 8 | $1,580.17 | $1,345.46 | $234.71 | $248,157.32 |
| 9 | $1,580.17 | $1,344.19 | $235.98 | $247,921.34 |
| 10 | $1,580.17 | $1,342.91 | $237.26 | $247,684.07 |
| 11 | $1,580.17 | $1,341.62 | $238.55 | $247,445.53 |
| 12 | $1,580.17 | $1,340.33 | $239.84 | $247,205.69 |
What this means
- Early payments are mostly interest because interest is charged on the outstanding balance. The split shifts toward principal as the balance falls.
- Note the halfway point: on a 30-year loan at typical rates, you do not owe half the original principal until somewhere around year twenty.
- Extra payments applied early save far more than the same amount applied late, because they remove interest for every remaining month.
How the loan amortization calculation works
Amortisation is the schedule that turns a loan balance into a series of equal payments. The payment never changes, but what it does changes completely: at the start it is nearly all interest, and by the end it is nearly all principal.
This is why the halfway figure surprises people. On a 30-year mortgage at 6.5%, roughly 77% of the first payment is interest, and the balance does not fall to half the original amount until around year twenty-one. Nothing is wrong — that is simply what charging interest on an outstanding balance produces.
It also explains why early extra payments are so effective. A dollar of extra principal in year one removes interest on that dollar for 359 remaining months. The same dollar in year twenty-five removes almost nothing.
The schedule below is the same one your lender uses. Comparing it against your statement is a reasonable way to check that extra payments are being applied to principal rather than being held as a prepaid instalment.
Frequently asked questions
Why is so much of my early payment interest?
Interest is charged on the balance you still owe, and at the start you owe nearly the whole loan. As the principal falls, the interest portion falls with it.
Is it better to pay extra monthly or one lump sum?
Timing matters more than structure — earlier is better. Consistent monthly extras usually beat a single later lump sum of the same total.
Do biweekly payments really help?
Yes, but not magically. Paying half the payment every two weeks produces 26 half-payments, or 13 full payments a year, which is really just one extra payment annually.
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Disclaimer. This calculator is provided for general information and educational purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Results are estimates based on the inputs you provide and the assumptions described above. Confirm any figure with a qualified professional before acting on it.