Loan Calculator
Estimate your monthly payment, total interest, and full amortization schedule for personal or auto loans. Adjust the rate, term, and extra payments to see how to pay off early.
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Balance & cumulative interest over time
Pay off early
Amortization schedule
| Month | Payment | Principal | Interest | Balance |
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How loan amortization works
Amortization is the process of paying off a loan in equal, scheduled installments. Each monthly payment is split into two parts: interest (the cost of borrowing, based on your remaining balance) and principal (the amount that actually reduces what you owe). Early in the loan, most of each payment goes toward interest. As the balance shrinks, more of each payment shifts toward principal — a pattern called an amortization curve.
The loan payment formula
Every fixed-rate installment loan uses the same standard amortization formula to compute the monthly payment M:
Where P is the loan principal, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. For example, a $25,000 loan at 8% APR over 60 months has a monthly rate of 0.00667, producing a payment of about $506.95. The special case where the rate is zero simplifies to M = P ÷ n.
How to reduce the interest you pay
- Make extra payments. Even $50–$100 extra per month goes straight to principal and can save thousands over the life of the loan. Use the "Pay off early" tool above to model it.
- Choose a shorter term. A 36-month term usually has a lower rate than 72 months, and you pay interest for far less time.
- Improve your credit before borrowing. A higher credit score unlocks lower APRs, which compound into large savings.
- Shop lenders and refinance. If rates drop or your credit improves, refinancing into a lower rate can cut your payment and total cost.
- Make biweekly payments. Half-payments every two weeks add up to one extra full payment per year, shortening the term.
Differences between loan types
Auto loans (new) are secured by the vehicle and typically carry the lowest consumer rates (often 5–8%), because newer cars hold value and are easy to repossess. Auto loans (used) usually run a couple of points higher since older vehicles depreciate faster. Personal loans are usually unsecured — there is no collateral — so lenders charge more (commonly 10–20%) to offset the risk. Student loans often offer the lowest rates and flexible terms, sometimes with government backing that limits the lender's risk. Use the preset buttons above to apply representative rates for each.
Tips for using this calculator
- Adjust the interest-rate slider to compare offers from different lenders.
- Toggle between 12 and 84 months to see how term length affects total cost.
- Enter an extra payment to instantly see how much sooner you'll be debt-free.
- Your inputs are saved automatically in your browser — nothing is sent anywhere.
Disclaimer
This calculator provides estimates for educational purposes only. Actual rates, fees, and terms vary by lender and credit profile. Always confirm final numbers with your lender before signing.