Loan Calculator
Enter your loan amount, interest rate, and repayment period. See your monthly payment, total interest cost, and total amount you'll repay over the life of the loan.
Background
A loan calculator determines your fixed monthly payment for any installment loan. You enter three values — how much you're borrowing, the annual interest rate (APR), and the repayment period — and it tells you what you'll pay each month, how much goes to interest, and the total cost of the loan.
This works for auto loans, personal loans, student loans, or any fixed-rate installment debt. The calculator uses the same amortization formula that banks and lenders use when generating your loan documents.
Enter your loan details
Type the amount you plan to borrow. Set the APR (Annual Percentage Rate) from your lender quote, and pick the repayment term. Everything updates as you type.
How to use this loan calculator
Enter the loan amount
How much do you plan to borrow? Type the principal amount.
Set the interest rate
Enter the APR from your lender. Use the slider to compare rates quickly.
Pick the term & read results
Choose a repayment period. Your monthly payment, total interest, and payoff cost appear instantly.
Formula & Equation Used
The standard fixed-rate loan payment formula (same as mortgage amortization):
Where: M = monthly payment, P = principal, r = monthly rate (APR ÷ 12 ÷ 100), n = total payments (months).
Try it yourself
Example Problem & Step-by-Step Solution
You're financing a used car for $18,000 at 6.9% APR for 48 months. What's the monthly payment and total interest?
Frequently Asked Questions
What's the difference between APR and interest rate?
The interest rate is the cost of borrowing the principal. APR (Annual Percentage Rate) includes the interest rate plus fees and charges, giving you the true annual cost. APR is always equal to or higher than the interest rate. Always compare APRs when shopping for loans.
How does a shorter term save money?
A shorter term means higher monthly payments but less time for interest to accumulate. A $20,000 loan at 7% costs $4,764 in interest over 5 years but only $2,239 over 3 years — saving you $2,525 despite higher monthly payments.
Can I pay off a loan early?
Most personal and auto loans allow early payoff without penalty. Check your loan agreement for a prepayment penalty clause. Making extra payments toward the principal reduces total interest and shortens the loan term.
What credit score do I need for a good rate?
For the best auto loan rates (under 5%), you typically need a credit score of 720+. Scores of 660-719 get average rates. Below 600, expect rates above 10-15%. For personal loans, the thresholds are similar but rates are generally higher across the board.
Types of loans
Auto loans
Personal loans
Student loans
Average loan rates by type
Credit card interest and payday loans cost dramatically more than installment loans. Consolidating credit card debt into a personal loan can save thousands in interest.
Loan numbers
FAQ
How do I calculate monthly loan payments manually?
Divide the APR by 12 for the monthly rate. Count the total months. Apply the formula: M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]. For a rough estimate, multiply the loan by the monthly rate and add a bit for principal paydown.
Is it better to make biweekly payments?
Biweekly payments (half your monthly payment every 2 weeks) result in 26 half-payments per year — equivalent to 13 monthly payments instead of 12. That extra payment goes to principal and can shorten a 5-year loan by several months.
What is amortization?
Amortization is the process of paying off a loan through scheduled payments. Each payment covers interest first, then principal. Early in the loan, most of your payment is interest. By the end, most goes to principal. This calculator uses the standard amortization formula.