Introduction
An installment loan is money you borrow and pay back in equal payments over a set period of time. Car loans, personal loans, and student loans are all common examples. Each payment you make covers two things: part of the original amount you borrowed (the principal) and a fee charged by the lender (the interest).
This installment loan calculator shows you exactly how much each payment will be, how much interest you will pay in total, and when your loan will be fully paid off. Enter your loan amount, interest rate, and loan term to get results right away. You can also adjust the compounding frequency, payment frequency, and payment timing to match your specific loan.
The calculator builds a full amortization schedule so you can see how each payment is split between principal and interest. It also lets you add extra payments — monthly, yearly, or one-time — to see how much money and time you can save by paying ahead. A step-by-step breakdown of the math is included so you can understand exactly how your numbers are calculated.
How to Use Our Installment Loan Calculator
Enter your loan details below to find out your payment amount, total interest cost, payoff date, and full amortization schedule.
Loan Amount — Type in the total amount of money you plan to borrow. This is the principal before any interest is added.
Annual Interest Rate — Enter the yearly interest rate on your loan. You can find this number in your loan offer or agreement.
Compounding Frequency — Pick how often your lender adds interest to the balance. Most personal loans use "Monthly (APR)." If you are not sure, leave it on the default setting.
Payment Frequency — Choose how often you will make payments. Options range from daily to once a year. Most loans use monthly payments.
Loan Term — Years and Months — Enter the length of your loan in years and months. You can also drag the slider to set the total term. The years and months fields update automatically when you move the slider.
Payment Timing — Select whether you pay at the end or the start of each period. Most loans use "End of Period." Choose "Start of Period" if your first payment is due right away.
Loan Start Date — Pick the month and year your loan begins. This sets the dates in your amortization schedule.
Extra Payments (optional) — Click "Add Extra Payments" to enter additional amounts you want to put toward your loan. You can add a monthly extra, a yearly lump sum, or a one-time payment. The calculator will show you how much interest you save and how much sooner you pay off the loan.
Press the Calculate button to see your results. Press Reset to clear all fields and start over.
What Is an Installment Loan?
An installment loan is money you borrow and pay back in equal payments over a set period of time. Each payment you make is called an installment. Common examples include car loans, personal loans, and student loans. Mortgages are also a type of installment loan.
How Installment Loans Work
When you take out an installment loan, the lender gives you a lump sum of money called the principal. You agree to pay it back with interest, which is the fee the lender charges you for borrowing. Your payments are spread out over months or years until the full amount is paid off.
Each payment is split into two parts. One part goes toward the principal, and the other part covers the interest. Early in the loan, most of your payment goes toward interest. Over time, more of your payment goes toward the principal. This shift is shown in what is called an amortization schedule, which is a table that breaks down every single payment.
Key Terms to Know
- Principal: The original amount you borrow before interest is added.
- Interest Rate: The yearly percentage the lender charges you on the money you owe.
- Loan Term: The total length of time you have to repay the loan.
- Compounding Frequency: How often interest is calculated and added to your balance. Monthly compounding is the most common. The way compound interest accumulates directly affects how much you owe over time.
- Extra Payments: Additional money you pay beyond the required amount. This reduces your balance faster, lowers total interest, and can help you pay off the loan early.
Why Extra Payments Matter
Making extra payments on an installment loan saves you money. Even a small extra amount each month reduces the principal faster. Since interest is calculated on the remaining balance, a lower balance means less interest. Over the life of a loan, this can save you hundreds or even thousands of dollars and shorten your payoff date. If you are carrying balances across multiple loans or credit cards, tools like a debt payoff calculator or a debt snowball calculator can help you build a strategy to eliminate all your debt faster.