Loan Calculator
Calculate your monthly payment, total interest, and payoff date for any amortized loan — and see how extra payments help.
Reviewed October 7, 2026 Runs in your browser — inputs are never stored
This tool provides general financial estimates for educational purposes only and is not personalized financial, tax, or investment advice. Consult a licensed financial professional before making major financial decisions.
About the Loan Calculator
A loan calculator is a financial planning tool that estimates your monthly payment, total interest, and payoff date for any amortised personal or auto loan. It is built for borrowers comparing offers, car buyers budgeting a purchase, students weighing repayment, and anyone considering a new instalment loan. Enter the amount, annual interest rate, term, and any extra monthly payment, and the calculator breaks each payment into principal and interest, showing how the balance retires over time. Because early payments are mostly interest, the tool makes the true cost of borrowing visible at a glance, and it demonstrates how even a small extra monthly payment can shorten the term and cut total interest significantly. The amortisation maths runs locally in your browser, so your figures stay private. Whether you are signing a new agreement, refinancing, or simply testing scenarios, the calculator gives you a clear, instant picture of your commitment. For binding decisions, always confirm the exact figures with your lender.
How to use it
- 1Enter the loan amount (principal) you plan to borrow.
- 2Type the annual interest rate as a percentage (for example 7.5, not 0.075).
- 3Choose the term in years or months, matching the field label.
- 4Optionally add an extra monthly payment to see interest savings.
- 5Press Calculate to view payment, total interest, and payoff timeline.
Worked example
borrow $15,000 at 6.9% APR for 5 years with no extra payments. The calculator returns a monthly payment of about $296, total interest of about $2,780, and a payoff after 60 months. Adding $50 extra each month shortens the term and cuts hundreds of dollars in interest — use that comparison when deciding whether to overpay.
How it works
How it works
An amortized loan splits each payment between interest and principal. Early payments are mostly interest; later ones mostly principal.
Formula
Payment = P × r / (1 − (1+r)⁻ⁿ) where P is the amount, r the monthly rate, and n the number of months.
Tip
Even small extra monthly payments can shorten your term and cut total interest significantly.
Who it is for
Borrowers comparing personal or auto loan offers, car buyers budgeting a purchase, students weighing repayment plans, and anyone considering a new instalment loan or refinancing an existing one.
Why it helps
Early payments are mostly interest, so the true cost of borrowing is invisible without an amortization breakdown — the tool shows total interest and how even a small extra payment shortens the term.
Tips for better results
- Enter the annual interest rate (e.g. 7.5), not the monthly rate — the calculator converts it internally.
- Add even $25–$50 extra per month to see how much interest and how many months you save over the life of the loan.
- Compare two or three terms (3, 5, 7 years) side by side to find the balance between affordable payments and low total interest.
- Re-run the numbers whenever your lender quotes a new rate or you consider refinancing.
Common mistakes to avoid
- Entering a monthly interest rate where the annual rate is expected, which understates the payment by ~12×.
- Forgetting to include origination fees, insurance, or taxes in the amount you actually borrow.
- Confusing the loan term in months with the term in years when comparing offers.
- Assuming the monthly payment equals total cost ÷ term — it ignores the interest that compounds on the declining balance.
Frequently asked questions
A:The process of paying off a loan through regular equal payments over time, gradually reducing the balance.
A:Yes — extra payments go straight to principal, reducing the balance faster and lowering total interest.
A:Yes, any fixed-rate installment loan works, including personal and auto loans.
Reviewed for accuracy · Last updated October 7, 2026
Formulas follow standard amortization, present/future value, and compounding mathematics used throughout the financial industry, and are periodically checked against reference calculations.
CalcWisee Editorial Team
Calculator development and formula review
CalcWisee is an independent site founded by Ayman. Every calculator is built from a published formula or official definition, tested against hand-worked examples before it goes live, and corrected promptly when a reader reports an issue to ayman@calcwisee.com.
Expertise: Financial mathematics, Health and fitness formulas, Applied mathematics, Unit conversion standards
References & sources
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