What Is a Personal Loan Calculator?
A personal loan calculator estimates the fixed monthly payment on an amortizing loan, along with the total interest you will pay and the overall cost of the loan. It works for any installment loan with a fixed rate and term, such as personal, auto, or debt-consolidation loans. The math is universal and not specific to any country.
How to Use It
Enter three values: the loan amount (principal), the annual interest rate as a percentage, and the term in years. The calculator converts the annual rate to a monthly rate, the term to a number of monthly payments, and applies the standard amortization formula to return your monthly payment, total interest, and total paid.
The Formula Explained
The payment formula is $$M = \frac{P \cdot r \cdot (1+r)^n}{(1+r)^n - 1}$$ where P is the principal, r is the monthly interest rate (annual rate divided by 12, expressed as a decimal), and n is the total number of monthly payments (years \(\times\) 12). If the rate is 0%, the payment is simply \(P \div n\).
Worked Example
Suppose you borrow $10,000 at 7.5% annual interest over 5 years. The monthly rate is \(0.075/12 = 0.00625\) and \(n = 60\) payments. Plugging into the formula gives a monthly payment of about $200.38. Over 60 months you pay roughly $12,022.59 in total, of which about $2,022.59 is interest.
FAQ
Does this include fees? No. It models principal and interest only. Origination fees, insurance, or prepayment penalties are not included.
Can I use it for a 0% loan? Yes. With a 0% rate the payment is the principal divided by the number of months.
Why is total interest higher for longer terms? A longer term lowers the monthly payment but means you pay interest over more months, increasing total interest paid.
