# Loan calculator

> A personal loan payment comes from the amount, the APR, and the number of months. A $15,000 loan at an example 12% APR over 36 months costs $498.21 a month and $2,935.73 in interest. An origination fee of 4% ($600) is taken from the funds you receive, which lifts the true cost to an effective APR near 14.86%.

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

## How a personal loan payment works

Most personal loans are installment loans: you borrow a lump sum and repay it in equal monthly payments. Each payment covers the month's interest, and the rest reduces what you owe. Early payments are mostly interest.

```
Monthly rate r = APR ÷ 12
Payment = amount × r ÷ (1 − (1 + r)^−months)
Total interest = payment × months − amount
```
Example: $15,000 at 12% for 36 months. r = 0.01, so the payment is $498.21 and interest is $2,935.73.

To see every payment split into interest and principal, use the [amortization schedule calculator](https://www.calterix.com/en-us/simulator/amortization/). To see what extra payments save, try the same tool's extra payments tab.

## Origination fees and the real cost

Some lenders charge an origination fee, often shown as a percent of the loan. It is usually subtracted from the money you receive, but you still repay the full amount. On $15,000 with a 4% fee, you get $14,400 and repay $15,000 plus interest.

| Fee | You receive | Effective APR |
| --- | --- | --- |
| 0% | $10,000 | 12.00% |
| 2% | $9,800 | 13.41% |
| 5% | $9,500 | 15.61% |
| 8% | $9,200 | 17.90% |

$10,000 loan at an example 12% APR for 36 months. Effective APR counts the fee.

When you compare lenders, line up the APR, the fee, and the term, then use the Compare two offers tab. A lower rate with a high fee can cost more than a higher rate with no fee.

## Payment by APR

| APR | Monthly payment | Total interest |
| --- | --- | --- |
| 8% | $313.36 | $1,281.09 |
| 12% | $332.14 | $1,957.15 |
| 16% | $351.57 | $2,656.53 |
| 20% | $371.64 | $3,378.89 |
| 24% | $392.33 | $4,123.83 |
| 30% | $424.52 | $5,282.57 |

$10,000 over 36 months. Rates are examples. Enter yours for real numbers.

## Common mistakes with loans

- Comparing interest rates without fees. The APR on the official disclosure includes certain fees, so compare APR to APR.
- Picking the longest term for the lowest payment. Total interest grows with every added month.
- Borrowing the exact amount you need without counting a fee taken from the funds.
- Using one loan to pay another without checking the new total cost.

If the debt is a credit card, use the [credit card payoff calculator](https://www.calterix.com/en-us/simulator/credit-card-payoff/). For a vehicle, see the [auto loan calculator](https://www.calterix.com/en-us/simulator/auto-loan/).

## Frequently asked questions

### How do I calculate a personal loan payment?

Use the loan formula: amount times the monthly rate, divided by 1 − (1 + rate)^−months. A $15,000 loan at 12% APR for 36 months is $498.21 a month.

### What is an origination fee on a loan?

It is a one-time charge for processing the loan, usually a percent of the amount. Lenders often take it out of the funds you receive, so you repay more than you get. A 4% fee on $15,000 is $600.

### How do I compare two loan offers?

Compare the total cost of each, meaning interest plus fees over the full term, and the monthly payment. On $15,000, a 12% loan for 36 months with no fee costs $2,935.73, while a 9.5% loan for 48 months with a 3% fee costs $3,538.66.

### How do I find the interest rate from a payment?

Use the Find the APR tab with the amount, payment, and number of months. A $10,000 loan repaid at $340 for 36 months works out to an APR of about 13.63%.

### Is a longer loan term cheaper?

A longer term lowers the monthly payment but raises total interest. Choose the shortest term that fits your budget.

### What APR should I expect on a personal loan?

Rates depend on your credit, income, loan size, and the lender, so no single number fits everyone. The rates here are examples. Prequalify with a few lenders and enter the real APR from each offer.