Loan Calculator
Estimate monthly payments and total interest for a fixed-rate personal loan, auto loan, or installment loan. Change the amount, rate, and term to compare repayment scenarios.
Formula
The calculator uses a standard amortized loan formula for equal monthly payments.
Payment = P × [r(1 + r)^n] / [(1 + r)^n - 1]
P is the principal, r is the monthly interest rate, and n is the number of monthly payments.
Example
A $25,000 loan at 7.25% for 5 years is paid over 60 monthly payments. The calculator estimates the monthly payment, then multiplies it by 60 to estimate total paid and total interest.
Common mistakes
- Using annual interest as if it were monthly interest.
- Forgetting origination fees, title fees, taxes, or insurance costs.
- Comparing only monthly payment instead of total interest.
FAQ
Can I use this for an auto loan?
Yes, if the auto loan has a fixed rate and equal monthly payments. Taxes and dealer fees are not included unless you add them to the loan amount.
What happens if I choose a longer term?
A longer term usually lowers the monthly payment but increases the total interest paid over the life of the loan.
Does this support extra payments?
Not yet. This first version estimates a regular fixed payment schedule without prepayments.