Use this calculator to estimate the monthly payment and total interest on any fixed-rate loan — personal loans, business loans, or any amount you're financing. Enter the loan amount, annual interest rate, and term in months to see your payment breakdown, along with a plain-language explanation of the amortization formula behind it.
A loan of 25,000 at 6.5% annual interest over 60 months results in a monthly payment of 489.15.
A standard installment loan is repaid through equal periodic payments that combine principal and interest, calculated so the balance reaches exactly zero at the end of the term — a process called amortization.
P is the loan amount, r is the periodic interest rate, and n is the total number of payments. A $15,000 loan at 8% APR over 4 years (48 months) results in a payment of about $366/month and roughly $2,568 total interest.
| Term | Monthly payment | Total interest |
|---|---|---|
| 2 years | $678 | $1,278 |
| 3 years | $470 | $1,912 |
| 4 years | $366 | $2,568 |
| 5 years | $304 | $3,246 |
$15,000 loan at 8% APR — monthly payment vs. total interest by term
Example 1 — Personal loan for debt consolidation: A $12,000 loan at 11% APR over 3 years results in a payment of about $393/month, with total interest of roughly $2,148.
Example 2 — Business equipment loan: A $50,000 loan at 7.5% over 5 years costs about $1,002/month, totaling roughly $10,120 in interest over the loan's life.
Example 3 — Comparing 2-year vs. 5-year for the same $15,000 loan: As shown in the table below, choosing 5 years over 2 years cuts the monthly payment by more than half but more than doubles total interest paid — the fundamental term-length trade-off.
| Fixed rate | Variable rate | |
|---|---|---|
| Payment predictability | Stays the same for the whole term | Can change as market rates move |
| Starting rate | Often slightly higher | Often slightly lower initially |
| Best for | Budgeting certainty, longer terms | Short terms, expecting rates to fall |
Can this work as a student loan repayment calculator? Yes — enter your student loan balance, interest rate, and desired term to see your monthly payment and total interest, the same way you would for any other installment loan.
How do I use this for house loan early payoff? Enter your current mortgage balance and rate, then compare the standard schedule against a shorter term or extra monthly payments to see how much interest an early payoff would save.
What's the difference between interest rate and APR? The interest rate reflects only the cost of borrowing the principal; APR also folds in certain fees, giving a fuller picture of total cost.
Can I pay off a loan faster than scheduled? Most loans allow this and it reduces total interest, but check your loan agreement for any prepayment penalty clauses.
Why did my lender quote a different payment than this calculator? Differences often come from rounding, fees, insurance add-ons, or a slightly different rate than initially quoted.
How does my credit score affect my loan rate? Lenders use credit score, income, and debt-to-income ratio to price risk — generally, higher scores unlock lower rates and better terms.
What's the difference between a secured and unsecured loan? A secured loan is backed by collateral (like a car or savings account) that the lender can claim if you default, which typically allows a lower rate than an unsecured loan based on creditworthiness alone.
Does making a payment on the 1st vs. the 15th of the month change total interest? For most standard fixed-payment loans, the payment date has little effect as long as payments are made on schedule; the schedule is built around the payment frequency, not the calendar date, though late payments can trigger fees or extra accrued interest.
What happens if I miss a payment? Missed payments typically trigger late fees, may be reported to credit bureaus, and can cause remaining interest to accrue on a higher effective balance depending on the loan's terms.
For a $15,000 loan at 9% APR over 4 years, the monthly payment works out to roughly $373, with total interest of about $2,904 over the life of the loan — compared to a 2-year term at the same rate, which would have a higher monthly payment near $685 but only about $1,440 in total interest.
APR: Annual Percentage Rate — the interest rate plus most lender fees, expressed as a yearly rate.
Origination fee: An upfront fee some lenders charge to process a new loan, often 1–8% of the loan amount.
Unsecured loan: A loan not backed by collateral, relying only on your creditworthiness and promise to repay.
Term: The length of time you have to repay the loan in full.