What this loan calculator does
Enter three numbers — how much you're borrowing, the annual interest rate, and how long you'll take to pay it back — and this calculator shows you the four figures that actually matter: your monthly payment, the total you'll hand over across the life of the loan, how much of that total is pure interest, and the month you'll make your final payment. It uses the standard amortization formula that banks, credit unions, and auto lenders all use, so the payment you see here is the payment you'd see on a real loan offer with the same terms.
The number most people skip past is the one worth staring at: total interest paid. A $25,000 loan at 7.5% doesn't cost $25,000 — over five years it costs roughly $30,000, and that extra $5,000 is the price of borrowing. Seeing the interest share as a proportion of everything you'll pay is often the moment a loan decision gets real. The green-and-amber bar under your result makes that split visible at a glance.
The amortization schedule below the result shows where every dollar of every payment goes. In month one of a typical five-year loan, a surprisingly large slice of your payment is interest; by the final year it's almost all principal. If you've ever wondered why your balance barely moves in the first year of a loan, the schedule is the answer, laid out payment by payment.
How to use it
- Enter the loan amount — the total you're borrowing, before interest.
- Enter the APR from your loan offer or quote. Use the APR, not just the "interest rate," if both are listed — APR includes lender fees and is the truer cost.
- Set the term in years or months. Results update instantly as you type.
- Compare scenarios by changing one input at a time — the fastest way to see what a shorter term or a lower rate is actually worth to you.
- Use Copy summary to save or share your numbers.
Frequently asked questions
How is a monthly loan payment calculated?
Lenders use the amortization formula: the loan amount multiplied by the monthly interest rate, divided by one minus (1 + monthly rate) raised to the negative number of payments. It looks intimidating written out, but the effect is simple — it produces one fixed payment that covers that month's interest and chips away at the balance, sized so the balance hits exactly zero on the final payment. This calculator applies that exact formula.
What is an amortization schedule?
A payment-by-payment table showing how each payment splits between interest and principal, and what you still owe afterward. Early payments are mostly interest because interest is charged on a large balance; later payments are mostly principal. The schedule above shows this for your exact loan — the year-end rows are highlighted so you can track progress annually.
Does this work for auto loans, personal loans, and student loans?
Yes. Any fixed-rate installment loan uses the same math — auto, personal, student, boat, RV, debt consolidation. What changes between loan types is the rate you're offered and the terms available, not the formula. For home loans specifically, property tax, insurance, and PMI complicate the picture; a dedicated mortgage calculator handles those better.
Why does so much of my early payment go to interest?
Because interest is charged on the remaining balance, and the balance is at its peak when you start. On a $25,000 loan at 7.5%, your first month's interest is about $156 — that gets paid before a single dollar touches the principal. As the balance falls, the interest slice of each identical payment shrinks and the principal slice grows. It's not a trick; it's just how balance-based interest works.
How can I pay less total interest?
Three levers: a shorter term, a lower rate, or extra principal payments. The term lever is the easiest to test here — switch a 5-year term to 4 years and compare the total-interest lines. Your monthly payment rises, but the lifetime cost usually drops by a meaningful amount. Extra payments work the same way: anything above the required payment goes straight at the principal, which shrinks every future interest charge.
Is this calculator free? Do you store my numbers?
Free, no account, no limits. Everything is calculated in your browser — your loan details are never sent to a server or stored anywhere.
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This calculator is for informational purposes only and is not financial advice. Actual loan offers depend on your credit profile, lender fees, and terms. Confirm figures with your lender before making decisions.