Loan Calculator
Calculate monthly payments, total interest, and view a full amortization schedule for any fixed-rate loan.
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Free Loan Calculator with Amortization Schedule
The SmarterSources Loan Calculator helps you understand the true cost of borrowing. Enter a loan amount, interest rate, and term to instantly see your monthly payment, total interest paid, and a complete month-by-month amortization schedule. It works for mortgages, auto loans, personal loans, and any other fixed-rate loan. Everything runs in your browser with no data sent anywhere.
How the Loan Calculator Works
The calculator uses the standard amortization formula to compute your monthly payment:
M = P[r(1+r)^n] / [(1+r)^n - 1]
Where P is the principal (loan amount minus any down payment), r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. This formula ensures each payment covers the interest owed for that month plus a portion of the principal, with the loan fully paid off after the final payment.
Understanding the Amortization Schedule
The amortization schedule shows how each monthly payment is split between principal and interest. In the early months of a loan, most of your payment goes toward interest. As the remaining balance decreases over time, a larger share of each payment goes toward principal. The schedule helps you visualize this shift and understand exactly where your money goes each month.
The Impact of Down Payments
A down payment reduces the amount you need to borrow, which lowers both your monthly payment and total interest paid over the life of the loan. For example, on a $300,000 home with a $60,000 down payment at 6.5% interest over 30 years, you save approximately $110,000 in total interest compared to financing the full amount.
Fixed-Rate vs. Variable-Rate Loans
This calculator is designed for fixed-rate loans where the interest rate stays the same for the entire loan term. If you have a variable-rate loan (ARM, adjustable-rate mortgage), the actual payments will change when the rate adjusts. You can still use this calculator to estimate payments at the current rate or at projected future rates.
Frequently Asked Questions
How is the monthly loan payment calculated?
The monthly payment uses the standard amortization formula: M = P[r(1+r)^n] / [(1+r)^n - 1]. P is the loan principal, r is the monthly interest rate, and n is the total number of payments. This formula ensures the loan is fully paid off at the end of the term.
What is an amortization schedule?
An amortization schedule is a month-by-month table showing how each payment is divided between principal and interest, along with the remaining balance. Early payments consist mostly of interest, while later payments are mostly principal.
Can I use this for a mortgage?
Yes. This calculator works for any fixed-rate loan including mortgages, auto loans, personal loans, and student loans. Enter the purchase price minus your down payment as the loan amount.
What if I enter a 0% interest rate?
With a 0% interest rate, the monthly payment is simply the principal divided by the number of months. The amortization schedule will show zero interest each month. This is common for some promotional auto financing.
Does a bigger down payment save money?
Yes. A larger down payment reduces the principal you borrow, which directly reduces both your monthly payment and the total interest paid over the loan's lifetime. Even a small increase in down payment can save thousands in interest.
Is my data private?
Yes. This calculator runs entirely in your browser. No financial data is sent to any server, no cookies are set, and nothing is stored.