Loan Calculator – Monthly Payment & Total Interest
Our free loan calculator helps you quickly determine your periodic payment amount, total interest paid, and overall repayment cost for any type of loan. Whether you're financing a car, a home improvement project, or a personal expense, understanding your loan terms upfront can save you thousands. Simply enter your loan amount, interest rate, and term to get an instant, accurate breakdown.
The total amount you are borrowing.
The yearly interest rate charged by the lender.
The length of time over which you will repay the loan.
How often you will make payments.
Your results will appear here
How to Use This Calculator
1. Enter the total loan amount you wish to borrow in the 'Loan Amount' field. 2. Input the annual interest rate quoted by your lender. 3. Select whether your loan term is expressed in years or months, then enter the term length. 4. Choose your payment frequency — monthly, bi-weekly, or weekly. 5. Click 'Calculate' to instantly see your payment per period, total amount paid, total interest charged, and the number of payments required.
How the Loan Calculator Works
This loan calculator uses the standard amortizing loan formula to determine the fixed periodic payment required to fully repay a loan over a set term at a given interest rate.
The Loan Payment Formula
The periodic payment P is calculated using:
- P = L × [r(1+r)^n] / [(1+r)^n − 1]
Where:
- L = Loan principal (amount borrowed)
- r = Periodic interest rate (annual rate ÷ number of periods per year)
- n = Total number of payment periods
Payment Frequency
The frequency of payments affects how the interest rate is divided and how many total payments you make. Monthly payments use 12 periods per year, bi-weekly use 26, and weekly use 52. Making more frequent payments can slightly reduce the total interest paid over the life of the loan.
Total Interest Paid
Total interest is calculated as: Total Interest = (Periodic Payment × Number of Payments) − Principal. This figure shows the true cost of borrowing beyond the principal amount.
Understanding Amortization
With an amortizing loan, each payment covers both interest and principal. Early in the loan, a larger portion goes toward interest; as time goes on, more of each payment reduces the principal. This is why paying extra early in the loan term can significantly reduce total interest costs.