LoanbieLoan Payment Calculator
Calculate the monthly payment for any amortizing loan — auto, personal, student, or business. Enter the loan amount, annual interest rate, and term in years to see your monthly payment, total interest, and how much of your early payments go toward interest versus principal.
Results are estimates for fixed-rate loans and update instantly. They run entirely in your browser — nothing is sent to a server.
How the Loan Payment Calculator works
Most installment loans are amortized, meaning you pay the same amount every month while the split between interest and principal changes over time. The monthly payment is:
M = P × r × (1 + r)n / ((1 + r)n − 1)
Where P is the principal, r is the monthly rate (APR ÷ 12), and n is the number of payments (years × 12). Interest is charged on the remaining balance, so early payments are interest-heavy and later payments are mostly principal.
Worked example
Worked example: a $10,000 personal loan at 5% APR for 5 years.
- Monthly payment: $188.71
- Total paid over the term: $11,322.74
- Total interest: $1,322.74
- First-month interest: $41.67; first-month principal: $147.05
Frequently asked questions
What is the loan payment formula?
M = P × r × (1 + r)^n / ((1 + r)^n − 1). P is the loan amount, r is the monthly interest rate (APR divided by 12), and n is the total number of monthly payments. This gives the fixed payment for an amortizing loan.
How much interest will I pay on a loan?
Multiply your monthly payment by the number of payments, then subtract the loan amount. The result is total interest. This calculator does it automatically — and you will notice that longer terms and higher rates increase total interest sharply.
What does it mean for a loan to be amortized?
An amortized loan is repaid in equal monthly installments over a fixed term. Each payment covers that month's interest plus part of the principal. Early payments are mostly interest; later payments are mostly principal.
Can I pay off my loan early?
Usually yes, but check for prepayment penalties. Making extra principal payments shortens the term and reduces total interest — every extra dollar goes straight to principal, so it stops accruing interest. Use the amortization schedule calculator to see the effect.