Loan Calculator
Estimate the monthly payment, total paid, and total interest on any loan from the amount, rate, and term.
About the Loan Calculator
The Loan Calculator turns three simple numbers — how much you're borrowing, the annual interest rate, and how long you have to pay it back — into the figures that actually matter: your fixed monthly payment, the total you'll hand over across the life of the loan, and how much of that is pure interest. Whether you're sizing up a car loan, a personal loan, a student loan, or a mortgage, it gives you a clear, instant estimate so you can compare offers and understand what a rate or term change really costs you.
Behind the scenes it uses the standard amortization formula that banks and lenders use for fixed-rate, fully-amortizing loans. Each payment covers the interest accrued that month first, and whatever is left chips away at the balance. Early on, most of your payment goes to interest; as the balance shrinks, more of every payment goes to principal. To make that visible, the tool includes a short amortization preview showing how the first few payments split between principal and interest, and how quickly the balance starts to fall. Everything runs directly in your browser, so it's fast, private, and works even without a connection once the page has loaded.
How to use
- Enter the loan amount — the principal, or the amount you're borrowing before any interest.
- Enter the annual interest rate as a percentage, such as
6.5. The tool converts it to a monthly rate for you. A rate of0is fine and simply splits the principal evenly across the term. - Set the term in years, and optionally add extra months if your loan isn't a whole number of years (for example, 5 years and 6 months).
- Read the results. The panel shows your fixed monthly payment, the total amount you'll pay, and the total interest. Below it, the amortization preview breaks down the first few payments.
Every value updates the instant you change an input, so you can try different rates or terms and immediately see how the monthly payment and lifetime interest respond. If a field is empty or invalid, the tool shows a dash instead of a confusing error, so you'll never see "NaN."
Frequently asked questions
How is the monthly payment calculated?
The tool uses the standard amortization formula: M = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where P is the principal, r is the monthly interest rate (the annual rate divided by 12 and by 100), and n is the total number of monthly payments. This produces the fixed payment that fully pays off the loan over the term. When the interest rate is 0%, it simply divides the principal evenly, so M = P ÷ n.
What do "total paid" and "total interest" mean?
Total paid is your monthly payment multiplied by the number of payments — the full amount that leaves your pocket over the life of the loan. Total interest is that figure minus the original principal, in other words the cost of borrowing. Watching how total interest changes as you adjust the rate or term is one of the most useful things this calculator does.
Can I enter a term with both years and months?
Yes. Enter the whole years in the "Term (years)" field and any extra months in the "+ Months" field. The tool adds them together into a total number of monthly payments, so 5 years and 6 months becomes 66 payments. Leave the months field at 0 for a whole-year term.
What is the amortization preview showing?
It lists the first few payments and, for each one, how much goes toward principal, how much goes toward interest, and the remaining balance afterward. Because interest is charged on the outstanding balance, the interest portion is largest at the start and shrinks over time while the principal portion grows — the preview makes that shift easy to see.
How accurate is this estimate?
The math is exact for a standard fixed-rate, fully-amortizing loan. Real-world quotes may differ slightly because lenders can round payments, add fees, insurance, or taxes, or compound interest on a different schedule. Treat the results as a solid, close estimate for comparison and planning rather than a formal quote from a lender.
Is my data sent anywhere?
No. The Loan Calculator runs entirely in your browser — nothing you type is uploaded, saved, or shared. All of the math happens locally on your device, which also means it keeps working offline once the page has loaded.