# Amortization schedule calculator

> An amortization schedule lists each loan payment split into interest and principal, plus the balance left. A $300,000 loan at an example 6.5% rate over 30 years has a $1,896.20 payment. Payment 1 sends $1,625.00 to interest and $271.20 to principal. Adding $200 a month pays the loan off in 23 years and 1 month and saves $103,448.79.

Source: https://www.calterix.com/en-us/simulator/amortization/ · Updated 11/06/2026 · en-US

## How amortization works

Amortizing a loan means paying it off in scheduled payments. For a fixed-rate loan, the payment stays level. Each month, the lender charges interest on the balance, and the rest of the payment cuts the balance. Because the balance starts high, early payments are mostly interest. As the balance falls, more of each payment goes to principal.

```
Interest = balance × APR ÷ 12
Principal = payment − interest
New balance = old balance − principal
```
Example: $300,000 at 6.5%. Interest in payment 1 = 300,000 × 0.065 ÷ 12 = $1,625.00. Principal = $1,896.20 − $1,625.00 = $271.20.

This schedule matches the way a [mortgage](https://www.calterix.com/en-us/simulator/mortgage/), an [auto loan](https://www.calterix.com/en-us/simulator/auto-loan/), or a [personal loan](https://www.calterix.com/en-us/simulator/loan/) is usually built. To compare it with a loan whose payment shrinks, see [fixed payment vs fixed principal](https://www.calterix.com/en-us/simulator/fixed-payment-vs-fixed-principal/).

## A sample schedule

| Payment | Interest | Principal | Balance after |
| --- | --- | --- | --- |
| 1 | $1,625.00 | $271.20 | $299,728.80 |
| 12 | $1,608.40 | $287.81 | $296,646.82 |
| 60 | $1,523.20 | $373.01 | $280,832.93 |
| 120 | $1,380.41 | $515.80 | $254,328.38 |
| 180 | $1,182.95 | $713.25 | $217,677.42 |
| 240 | $909.90 | $986.30 | $166,995.85 |
| 300 | $532.33 | $1,363.87 | $96,912.49 |
| 360 | $10.22 | $1,885.99 | $0.00 |

$300,000 at an example 6.5% for 30 years. Payment is $1,896.20 every month.

After 5 years (60 payments), only $19,167.07 of principal is paid, about 6% of the loan. The balance crosses the halfway point near payment 257, with 103 payments left.

Total interest over the 30 years is $382,633.47, which is 128% of the amount borrowed.

## How extra payments help

An extra payment that goes to principal lowers the balance right away, so later interest is charged on less. The regular payment stays the same, and the loan ends earlier. Ask your lender to apply extra money to principal, and check for any prepayment fee.

| Extra payment | Paid off in | Interest saved |
| --- | --- | --- |
| None | 30 years | $0.00 |
| $200 every month | 23 years and 1 month | $103,448.79 |
| $200 monthly plus $10,000 at payment 12 | 21 years and 6 months | $133,152.94 |
| $20,000 once, at payment 1 | 24 years and 11 months | $97,429.37 |

$300,000 at an example 6.5% for 30 years.

Money applied early saves the most. The same $20,000 paid at payment 1 saves far more than it would at payment 240.

## Common mistakes

- Assuming interest and principal split evenly. Early on, interest takes most of each payment.
- Sending extra money without telling the lender to apply it to principal.
- Forgetting that taxes, insurance, and fees are not part of the loan schedule.
- Comparing two loans on payment size alone, without total interest and term.

## Frequently asked questions

### What is an amortization schedule?

It is a table of every loan payment showing how much goes to interest, how much to principal, and the balance left afterward. A $300,000 loan at 6.5% for 30 years has 360 rows and a $1,896.20 payment.

### How do I calculate amortization?

Multiply the balance by the monthly rate to get interest, subtract that from the payment to get principal, and subtract principal from the balance. Repeat for each month.

### How much interest do I save by paying extra each month?

On $300,000 at 6.5% for 30 years, an extra $200 a month saves $103,448.79 in interest and ends the loan 6 years and 11 months sooner.

### Why is so much of my early payment interest?

Interest is charged on the full balance, and the balance is largest at the start. In payment 1 of the example loan, $1,625.00 of $1,896.20 goes to interest.

### Is it better to pay a lump sum early or small amounts monthly?

Money that reaches the loan earlier saves more interest, whatever the form. A one-time $20,000 at payment 1 saves $97,429.37, and $200 a month saves $103,448.79 over time. Use the Extra payments tab to test your own plan.

### What is the difference between APR and interest rate in a schedule?

The schedule here uses one rate, entered as APR, divided by 12 each month. Fees are not in the schedule, so add them separately if your lender charges them.