Loan Calculator

Free Online Loan Calculator

This loan calculator finds your monthly payment, total interest paid, total amount paid, and full amortization schedule for any fixed-rate loan — personal, auto, student, or mortgage. Enter the loan amount, interest rate, and term, and the results update instantly. Add an optional extra monthly payment to see how much interest and time you save.

The Loan Payment Formula

The standard amortizing loan formula calculates a fixed monthly payment that pays off the loan in equal installments over the term:

M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)

Where M is the monthly payment, P is the principal, r is the monthly interest rate (annual rate ÷ 12), and n is the number of payments. This is what the calculator uses, with each month re-applied to compute remaining balance, interest paid, and the full amortization table.

How to Use the Calculator

Type your loan amount, the annual interest rate (as a percentage), and the loan term in years. Optionally enter an extra monthly payment to model paying off faster. The four result boxes show your monthly payment, total interest, total paid, and the actual payoff time (which can be shorter than the term if you add extra payments).

Pay Off Sooner With Extra Payments

Adding even a small extra payment each month can dramatically reduce total interest. For example, a $25,000 5-year auto loan at 6.5% costs about $4,344 in interest. Adding just $50/month extra cuts that to roughly $3,690 — over $650 saved — and pays the loan off about 7 months early. The amortization schedule shows month by month exactly how the extra payment accelerates principal reduction.

Common Loan Types

• Personal loans — typically 2-7 year terms, rates from 6% to 36% depending on credit
• Auto loans — 3-7 year terms, rates from about 5% to 15%
• Student loans — 10-25 year terms; federal rates are fixed, private rates vary
• Mortgages — 15 or 30 year terms most commonly; rates depend on the market
• Credit cards — technically revolving credit, but if you pay a fixed amount monthly the same math applies

What the Amortization Schedule Shows

Each row in the amortization table shows the payment number, the monthly payment, how much of that went to principal, how much went to interest, and the remaining balance. Early in the loan, most of each payment is interest; later, more goes to principal. Seeing this shift is one of the best ways to understand the real cost of a long-term loan.

Frequently Asked Questions

Is this calculator accurate?

Yes. It uses the standard amortizing-loan formula and walks the schedule month by month with full floating-point precision. Real loans may include fees, taxes, insurance, or variable rates that this calculator does not model — for those, use the result here as a baseline.

Why is most of my early payment going to interest?

Because interest is charged on the remaining balance, which is high at the start. As the principal shrinks, less of each payment is needed for interest and more goes to principal. By the last year of the loan, almost the entire payment reduces principal.

Does this work for mortgages?

Yes — the formula is identical. Just enter your full mortgage principal and term (typically 15 or 30 years). For a complete picture of a mortgage, factor in property tax, homeowners insurance, and PMI separately, since those are added to the bank's payment but are not part of the loan math.

Should I make extra payments or invest the money?

If your loan rate is higher than the after-tax return you expect to earn from investing, extra payments win. If your rate is low (below ~4-5%) and you can earn more by investing, investing tends to come out ahead long-term. Use this calculator's "extra/mo" field alongside a compound interest calculator to compare the two paths.