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Loan Calculator

A free online loan calculator that works out your monthly payment, total interest, and total cost for any fixed-rate loan, plus how much time and interest extra monthly payments would save you.

How the Loan Calculator Works

Choose a loan type — personal, auto, mortgage, student, business, or other — for context, then enter your loan amount, APR interest rate, and loan term in years. Optionally add an extra monthly payment to see how much faster you could pay off the loan. The calculator instantly returns your monthly payment, payoff time, a principal-vs-interest visual split, total interest, and total cost of the loan. If you entered an extra payment, it also shows how many months and how much interest that extra payment would save compared to the base monthly payment, and you can toggle a year-by-year breakdown table showing principal paid, interest paid, and ending balance for each year.

How the Monthly Payment Is Calculated

The calculator uses the standard amortization formula for a fixed-rate loan: Payment = P × r ÷ (1 − (1 + r)⁻ⁿ), where P is the loan principal, r is the monthly interest rate (your APR divided by 12), and n is the total number of monthly payments (loan term in years multiplied by 12). This formula produces a fixed monthly payment that fully pays off the loan, principal and interest, by the end of the term. For a $25,000 loan at 6.5% APR over 5 years, this works out to a monthly payment of $489.15, total interest of $4,349.22, and a total cost of $29,349.22.

Extra Payments and the Yearly Breakdown

Adding an optional extra monthly payment reduces your outstanding principal faster than the base schedule, which means less interest accrues over the life of the loan and the loan is paid off sooner. The calculator compares your extra-payment scenario against your base monthly payment and reports the months saved and the interest saved. The togglable yearly breakdown table then shows, for every year of the loan, how much you paid toward principal, how much toward interest, and what your ending balance is — useful for seeing exactly how the balance shrinks and how the principal-to-interest ratio shifts as the loan matures.

Common Mistakes to Avoid

Using the monthly interest rate instead of APR

Solution:

The calculator expects your annual percentage rate (APR), not a monthly rate — it divides by 12 internally to get the monthly rate used in the amortization formula. Entering an already-monthly rate as if it were the APR will produce a payment far too low.

Entering the loan term in months instead of years

Solution:

The term field expects years, not months. Typing 60 instead of 5 for a five-year loan multiplies the term twelvefold and produces a wildly understated monthly payment.

Forgetting extra payments compound over time

Solution:

An extra monthly payment made early in the loan reduces principal while more of your regular payment would otherwise have gone to interest, so the same extra amount saves more in interest the earlier it starts. Waiting until later in the term to add extra payments saves less than starting immediately.

Confusing total interest with total cost of the loan

Solution:

Total interest is only the extra amount paid on top of the principal. Total cost of the loan is the full amount paid over the life of the loan — principal plus total interest combined. Reading one figure as the other misrepresents what the loan actually costs.

Ignoring fees, taxes, and insurance not included in this calculator

Solution:

This calculator computes principal and interest only. Real-world loans, especially mortgages and auto loans, often include origination fees, property taxes, insurance, or other charges that aren't part of this calculation, so your actual required payment may be higher than the figure shown here.

Assuming a 0% interest rate needs no calculation

Solution:

Even at 0% APR, the calculator still divides the loan amount evenly across the term to determine the monthly payment — it isn't skipped or left blank. A 0% rate simply means total interest is zero and total cost equals the loan amount.

Frequently Asked Questions

The loan type selector lets you choose personal, auto, mortgage, student, business, or other for context, but the underlying math is the same fixed-rate amortization formula for every type — the loan type doesn't change the calculation, only the label shown with your result.
No. It calculates principal and interest only. Property taxes, homeowners insurance, PMI, origination fees, and other charges are not included, so your actual monthly obligation on a real loan may differ from the result shown here.
It depends on your loan amount, rate, term, and how large the extra payment is, but even a modest extra amount each month can shorten your payoff time by months or years and save a meaningful amount in total interest, especially if you start the extra payments early in the loan.
This Loan Calculator gives you a quick summary — monthly payment, total interest, total cost, and an optional yearly breakdown. The dedicated Loan Amortization Calculator instead shows the full month-by-month payment schedule in detail, which is useful if you need to see every individual payment rather than a yearly summary.
The monthly payment is determined entirely by the loan amount, interest rate, and term using the standard amortization formula. The loan type field is included purely for your own context and record-keeping — it has no effect on the calculation.
Yes. At 0% APR, the calculator simply divides the loan amount evenly across the number of payments, since no interest accrues. Total interest will show as zero and total cost will equal the loan amount.
No. The calculator runs entirely locally in your browser. Your loan amount, rate, term, and any extra payment amount are never uploaded, logged, or stored on any server.

Key Features

  • Loan type selector — personal, auto, mortgage, student, business, or other, kept for context only and doesn't change the math.
  • Loan amount field — enter the principal you're borrowing.
  • APR interest rate field — enter your annual percentage rate.
  • Loan term in years — enter the length of the loan.
  • Optional extra monthly payment — add an extra amount to see how much faster you'd pay off the loan.
  • Monthly payment result — your required fixed monthly payment, calculated instantly.
  • Payoff time — how long it will take to pay off the loan given your inputs.
  • Principal-vs-interest visual split — a clear visual showing how much of your total cost is principal versus interest.
  • Total interest and total cost of loan — the full interest paid over the life of the loan, and the total amount you'll pay including principal.
  • Base monthly payment reference — shown alongside your result so you can compare against the extra-payment scenario.
  • Extra-payment savings message — a plain-English summary of months saved and interest saved if you add an extra monthly payment.
  • Togglable year-by-year breakdown table — principal paid, interest paid, and ending balance for each year of the loan.