Free loan calculator: monthly payment, total cost and total interest for any amount, rate and term. Instant results for car, personal and student loans.
The monthly loan payment formula is: M = P × r(1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12).
Example: $20,000 auto loan at 6% for 5 years: monthly rate = 0.06/12 = 0.005, n = 60 payments → monthly payment = $386.66. Total paid = $23,199. Total interest = $3,199.
Paying extra principal each month dramatically reduces total interest. On the example above, paying an extra $50/month saves $290 in interest and pays off the loan 5 months early. On larger loans and longer terms, the savings are even greater.
Each payment is split between interest and principal. Early payments are mostly interest; later payments are mostly principal. This is called amortization. Refinancing or making extra payments attacks the principal directly and reduces future interest charges.
Amortized loans — personal, auto, student — use the same formula as mortgages: a fixed payment covering interest on the outstanding balance plus enough principal to reach zero at term end. The payment is M = P × [r(1+r)^n] / [(1+r)^n − 1].
A $25,000 car loan at 8% over 60 months costs about $507 monthly, with total interest of roughly $5,415. Shortening to 48 months raises the payment to $610 but cuts interest to about $4,295.
What matters more, rate or term? Both — but long terms quietly multiply interest. A low payment over 84 months usually costs far more overall than a higher one over 48.
What is APR? The annual cost of the loan including most fees, letting you compare offers fairly.
Can I pay a loan off early? Usually yes, and it saves interest — check for prepayment penalties first.
The formulas and figures used by this calculator come from these published sources. Where a figure changes from year to year, the year it applies to is stated on the page.
Results are estimates for planning, not financial advice. Tax rules and rates vary by country and by personal circumstances.