Loan Calculator
See your monthly payment for an auto, personal or student loan — plus how extra payments can shorten your payoff time.
Loan Details
Amortization Schedule
| Year | Principal Paid | Interest Paid | Total Paid | Remaining Balance |
|---|
How This Loan Calculator Works
Enter your loan amount, interest rate and term to get your fixed monthly payment, calculated with the same amortization formula lenders use for auto, personal and student loans. Turn on extra monthly payments to see exactly how much time and interest you'd save by paying a little more each month.
Every result comes with a full month-by-month amortization schedule, already shown below your numbers — no need to click anything to reveal it. When you're done, download a summary of your results or copy them (with or without the full schedule) to save or share.
Understanding How Loans Work: Principal, Interest & Amortization
Whether you are financing a new car, consolidating credit card debt with a personal loan, or repaying student loans, understanding how loans are structured puts you in financial control. When you take out an installment loan, the lender grants a lump sum called the principal. In exchange, you commit to paying it back over a fixed timeline with interest—the cost charged for borrowing.
The Anatomy of Amortization: How Your Payments Shift
Most consumer installment loans in the United States use an amortizing payment schedule. This means your total monthly payment remains identical every single month, but what happens under the hood changes constantly:
- Early Payments: In the first phase of the loan, your remaining principal is at its highest. As a result, the largest portion of your monthly check goes toward interest charges, with only a small portion reducing the actual balance.
- Later Payments: As your principal balance shrinks month after month, interest charges naturally drop. Consequently, an increasingly large slice of every payment goes directly toward paying down your remaining principal until the loan is fully wiped out.
How Extra Monthly Payments Save Serious Money
When you make your regular monthly payment, interest takes its cut first. However, when you add an extra principal payment (even just $25, $50, or $100 extra per month), 100% of that extra cash attacks your remaining principal balance.
Because all subsequent interest calculations are based on that reduced balance, paying even a small extra amount creates a compounding snowball effect: it eliminates future interest charges and cuts months or years off your final payoff date.
Comparing Common U.S. Loan Types
Different loans serve different purposes and carry distinct interest rate benchmarks across the U.S. credit landscape:
- Auto Loans: Secured by the vehicle itself, which usually earns borrowers lower interest rates (typically 5% to 12% APR depending on whether the car is new or used, and your credit score). Standard loan terms range from 36 to 72 months.
- Personal Loans: Most commonly unsecured (meaning no collateral is backed), personal loans typically range from 7% to 24% APR and are used for emergency expenses, home improvements, or high-interest credit card consolidation. Terms usually span 2 to 5 years.
- Student Loans: Federal student loans offer standardized, fixed interest rates set by Congress (usually 5% to 9% APR) along with income-driven repayment plans and student loan protections. Private student loans vary by lender and co-signer credit.
Frequently Asked Questions
Monthly loan payments are calculated using standard loan amortization: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the loan amount, r is the periodic interest rate (annual APR divided by payment periods per year), and n is the total number of payments.
Yes. Extra payments go directly toward reducing your principal balance. Because subsequent interest is computed on the smaller remaining balance, extra payments shorten your payoff timeline and save significant interest over the life of the loan.
The interest rate is the baseline percentage charged on borrowed money. The Annual Percentage Rate (APR) reflects the true annual cost of borrowing, incorporating both the interest rate and mandatory lender fees or origination charges.
U.S. auto loans typically range from 5% to 12% APR depending on credit score and vehicle type. Personal loans range from 7% to 24% APR (unsecured), while federal student loans generally carry fixed rates between 5% and 9% APR.
Most modern U.S. auto loans, personal loans, and federal student loans have zero prepayment penalties, allowing you to pay off your balance early to save interest. Always review your loan promissory note for specific prepayment terms.