Loan Calculator
Calculate monthly payments, total interest and payoff for any loan.
All calculations happen locally in your browser — nothing is uploaded, stored or tracked.
Enter the loan amount
The principal you plan to borrow.
Set rate and term
Annual interest rate and the repayment term in years or months.
Review the results
Monthly payment, total interest, total cost and the full amortization schedule.
What Is a Loan Calculator?
A loan calculator works out the fixed monthly payment required to repay a loan over a set term at a given annual interest rate, then shows how that payment splits between interest and principal over time. The math is the standard amortization formula used by banks worldwide.
The calculator covers any fixed-rate, fixed-term loan — personal, auto, student or business. Payment frequency can be monthly or biweekly, and the assumptions (interest rate, term, fees) are always the values you enter; nothing is pulled from the internet.
The Amortization Formula
Where P is the principal, r is the monthly interest rate (annual rate ÷ 12 ÷ 100) and n is the number of payments. Total interest is then (payment × n) − principal. The amortization table shows the principal/interest split of every payment.
Your data never leaves your device.
Every calculation on this site runs in your browser using vanilla JavaScript. Nothing is uploaded, stored or tracked.
- 100% local, client-side calculations
- No data stored on any server
- No tracking, no analytics, no ads scripts
- Works offline once loaded
Frequently Asked Questions
How is a loan payment calculated?
Using the standard amortization formula: payment = P × r / (1 − (1 + r)^−n), where r is the monthly rate and n the number of payments.
How much interest will I pay on a loan?
Multiply your monthly payment by the number of payments and subtract the principal. The calculator shows this directly.
What affects my monthly payment most?
The interest rate and the term. A longer term lowers the payment but increases total interest; a higher rate raises both.
Is the interest rate compounded monthly?
The calculator assumes monthly compounding at the annual rate divided by 12, the standard convention for most consumer loans.
Does this include fees?
No — the result is principal and interest only. Add any origination fees or insurance separately.