# Fixed payment vs fixed principal

> A level payment loan charges the same amount every month, while a declining payment loan repays equal principal each month plus interest on the shrinking balance. On $250,000 at an example 6.5% over 30 years, the level payment is $1,580.17 and total interest is $318,861.22. The declining plan starts at $2,048.61, ends at $698.21, and costs $244,427.08 in interest.

Source: https://www.calterix.com/en-us/simulator/fixed-payment-vs-fixed-principal/ · Updated 11/06/2026 · en-US

## Level payment vs declining payment

Both plans charge the same interest rate. The difference is how principal is paid back.

- **Level payment** (also called fixed payment): the payment never changes. Early payments are mostly interest, and the share going to principal grows over time. This is how most U.S. mortgages and car loans work.
- **Declining payment** (fixed principal): you repay the same slice of principal every month, plus interest on the balance. The payment starts high and falls every month.

```
Level: payment = loan × r ÷ (1 − (1 + r)^−n)
Declining: payment in month k = loan ÷ n + (loan − (k − 1) × loan ÷ n) × r
r = rate ÷ 12, n = number of months
```
Example: $250,000, 6.5%, 360 months. Level payment $1,580.17. Declining first payment $694.44 + $1,354.17 = $2,048.61.

Level payments make budgeting easy. A declining payment loan pays down principal faster, so the balance and the total interest are lower. To play with real loan numbers, see the [amortization schedule calculator](https://www.calterix.com/en-us/simulator/amortization/) or the [mortgage calculator](https://www.calterix.com/en-us/simulator/mortgage/).

## Worked examples

| Term | Level payment | Level interest | Declining first payment | Declining interest |
| --- | --- | --- | --- | --- |
| 5 years | $4,891.54 | $43,492.22 | $5,520.83 | $41,302.08 |
| 10 years | $2,838.70 | $90,643.93 | $3,437.50 | $81,927.08 |
| 15 years | $2,177.77 | $141,998.31 | $2,743.06 | $122,552.08 |
| 30 years | $1,580.17 | $318,861.22 | $2,048.61 | $244,427.08 |

$250,000 at an example 6.5% rate.

On the 30-year loan, the declining plan saves $74,434.14 in interest but asks for $468.44 more in the first month. The longer the term, the bigger the gap between the plans.

## Balance and payment over time

| Payment number | Level plan balance | Declining plan balance | Declining payment |
| --- | --- | --- | --- |
| 60 | $234,027.44 | $208,333.33 | $1,826.68 |
| 120 | $211,940.32 | $166,666.67 | $1,600.98 |
| 180 | $181,397.85 | $125,000.00 | $1,375.29 |
| 240 | $139,163.21 | $83,333.33 | $1,149.59 |
| 300 | $80,760.41 | $41,666.67 | $923.90 |

$250,000, 6.5%, 30 years. The level payment stays $1,580.17.

After 10 years, the declining plan has paid down $83,333.33 of principal and the level plan only $38,059.68. The declining payment falls below the level payment at payment 126, a little over 10 years in.

## Which plan fits you

- A level payment is easier on a tight monthly budget, because the first payment is lower.
- A declining payment needs higher income at the start, but total interest is lower and the balance falls faster.
- If you can afford the declining first payment, you can often get a similar result with a level loan by paying extra each month. Try the extra payments tab in the [amortization calculator](https://www.calterix.com/en-us/simulator/amortization/).
- Most lenders in the U.S. offer level payment loans, so the declining plan is mainly a way to see the math.

## Frequently asked questions

### What is the difference between fixed payment and fixed principal?

A fixed payment loan charges the same total each month, while a fixed principal loan repays the same amount of principal each month plus interest, so the payment falls over time. On $250,000 at 6.5% for 30 years, the first starts at $1,580.17 and the second at $2,048.61.

### Which costs less in interest, level payments or declining payments?

Declining payments cost less, because principal drops faster. On $250,000 at 6.5% over 30 years, interest is $244,427.08 versus $318,861.22 with a level payment, a $74,434.14 difference.

### Why is the first payment higher with a declining payment loan?

The first payment includes a full slice of principal ($694.44 here) on top of interest on the whole balance. As the balance shrinks, interest and the payment shrink with it.

### When does the declining payment fall below the level payment?

On $250,000 at 6.5% over 30 years, the crossover is at payment 126, a little over 10 years in. Use the Crossover month tab for your own loan.

### What is a level payment loan called in the U.S.?

Lenders usually just say a fixed-rate loan with equal monthly payments. An amortization schedule shows how each payment splits between interest and principal.