Loan Calculator
Free calculator for any fixed-rate loan — mortgage, auto, student, or personal. See your monthly payment, total interest, and how much an extra payment each month saves you.
Monthly payment
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Total interest
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Total paid
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Payoff time
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How this loan calculator works
Enter your loan amount, annual interest rate, and term. The calculator uses the standard amortization formula — the same math as Excel's PMT function — to work out a fixed monthly payment that pays the loan off exactly at the end of the term. Add an extra monthly payment to see how much interest you save and how much sooner you finish.
What the results mean
- Monthly payment — what you pay each month (principal + interest), plus any extra.
- Total interest — the lifetime cost of borrowing on top of the amount you borrowed.
- Payoff time — how long until the balance reaches zero (shorter when you add extra payments).
Frequently asked questions
How is a monthly loan payment calculated?
It uses the amortization formula (Excel's PMT): principal and interest are spread evenly so the balance hits zero at the end of the term. Early payments are mostly interest; later ones are mostly principal.
What does an extra monthly payment do?
Every extra dollar goes straight to principal, cutting both the interest you pay and the time to payoff. Try increasing the "extra" field and watch the savings appear.
Is this calculator free?
Yes. For a downloadable Excel version with the full schedule and a multi-loan comparison, grab the Loan & Mortgage Calculator Suite.