Loan Calculator

How to use the loan calculator

1. Type the Loan amount, for example 25000 for a car loan or a line of credit you want to repay on a fixed plan.
2. Enter the Annual interest rate (%) quoted by the lender, such as 6.5.
3. Set the length of the loan with Years and Months. A 30-month loan is 2 years and 6 months, or simply 0 years and 30 months.
4. Choose the Payment frequency: monthly, semi-monthly, bi-weekly, weekly, quarterly or annually.
5. Leave Compounding on Same as payments for most consumer loans, or pick another option if your contract says so (see below).
6. Optionally add an Extra payment per period to see how much interest you save by paying a little more each time.

The results update as you type: the regular Payment, the Number of payments, the Total interest, the Total paid and, when you add an extra amount, the Interest saved (extra). The Amortization schedule lists every payment, or one line per year if you switch the view to By year, and Download CSV saves it for a spreadsheet. Open How it was calculated to see the formula with your numbers.

The loan payment formula

A fixed-payment (amortizing) loan uses the annuity formula:

P = L × i / (1 − (1 + i)^−n)

where L is the amount borrowed, i the interest rate per payment period and n the number of payments. With 25,000 at 6.5% over 5 years paid monthly, i = 0.065 / 12 ≈ 0.0054167 and n = 60, so the payment is 489.15.

Each payment first covers the interest accrued since the last one (balance × i); the rest reduces the principal. That is why early payments are mostly interest and later ones mostly principal. This tool rounds the interest to the cent every period, like a lender’s statement, and adjusts the last payment so that the balance ends at exactly zero.

Compounding and the rate per period

When compounding matches the payment frequency, the rate per period is simply the annual rate divided by the number of payments per year. When it does not, the tool converts the rate to an equivalent rate per payment: i = (1 + r/m)^(m/n) − 1, where m is the number of compounding periods per year and n the number of payments. For example, Canadian fixed-rate mortgages are compounded semi-annually; for those, the dedicated mortgage calculator also handles insurance and accelerated payments. The Rate per period result shows the exact value used.

Extra payments

An extra amount paid each period goes entirely to principal, so the balance falls faster, less interest accrues, and the loan ends early. The schedule shows the shorter payoff and the stats compare total interest with and without the extra amount. Check your contract first: some loans charge a prepayment penalty or limit extra payments.