Loan Interest Calculator
See the total interest a loan costs and what drives that number.
Total loan interest is everything you pay above the amount you borrowed. It grows with a higher rate and a longer term. On a $25,000 loan at 7.5% over 5 years the monthly rate is 7.5 / 12 = 0.625 percent, the payment is $500.95, and 60 x $500.95 = $30,057, so about $5,057 is interest; stretch the same loan to 7 years at the same rate and interest climbs to about $7,210. Enter your loan to see the total and how it changes.
This calculator is for general education. It is not financial advice and not a loan offer. It assumes a fixed rate, equal monthly payments and interest charged at the annual rate divided by 12, and it leaves out fees, insurance and any prepayment rules in your loan. Your lender's disclosures and statements are the final figures.
Estimated monthly payment
$500.95
Principal vs. interest paid per year
Amortization schedule
| Year | Principal | Interest | Balance |
|---|---|---|---|
| 1 | $4,282 | $1,730 | $20,718 |
| 2 | $4,614 | $1,397 | $16,104 |
| 3 | $4,972 | $1,039 | $11,132 |
| 4 | $5,358 | $653 | $5,774 |
| 5 | $5,774 | $237 | $0 |
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About the Loan Interest Calculator
Where a payment calculator answers what you owe each month, this tool focuses on the interest you pay across the whole loan. It is the difference between the total of all your payments and the amount you originally borrowed, and it is sensitive to both the rate and the term. Doubling the rate more than doubles the interest: on the same $25,000 over 5 years, going from 7.5% to 15% takes interest from about $5,057 to about $10,685. The term works more quietly. Each extra year keeps a balance outstanding longer, and every month of that balance is charged interest. The schedule below makes the pattern concrete. In the opening months a large share of your payment is interest, because it is charged on the full balance. On this loan the first payment is about $156 interest and $345 principal, and the principal share grows over time. That front-loading is why paying extra early, when the balance is largest, removes far more interest than the same dollar paid near the end. Total interest is a useful way to compare two loans, but it does not count fees.
Frequently asked questions
How is total loan interest calculated?+
Add up every monthly payment over the life of the loan, then subtract the amount you borrowed. What remains is the total interest. This calculator does that automatically from your amount, rate, and term.
Does a longer term mean more interest?+
Yes. A longer term lowers the monthly payment but keeps the balance outstanding for more months, so interest accumulates longer. The same loan over seven years can cost far more interest than over five, even at an identical rate.
Why is so much early payment interest?+
Interest is charged on the outstanding balance, which is highest at the start. So early payments carry more interest and less principal than later ones. As the balance falls, the interest portion shrinks and principal grows, even though the payment is fixed.
How do I pay less interest overall?+
Choose a lower rate, a shorter term, or pay extra toward principal, especially early when the balance is large. Even small additional payments in the first years cut total interest more than the same amount paid later.
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