APR Calculator (True Loan Cost)
A low interest rate can hide an expensive loan. This APR calculator adds origination and closing fees back in to show the true annual percentage rate you actually pay — the number worth comparing across offers.
How the APR calculator works
Two loans can advertise the same interest rate yet cost very different amounts. The difference is fees. APR — annual percentage rate — is the standardized figure that rolls fees into the yearly cost so you can compare offers fairly. This calculator finds it in three steps.
First it computes the monthly payment on the full loan amount using the stated rate and the standard amortization formula. That is the payment you will actually send the lender every month. Second, it subtracts your origination and closing fees from the loan amount to get your net proceeds — the cash that actually lands in your account. Third, it solves for the rate that makes the present value of all those payments equal to the net proceeds. Because you repay based on the full amount but only received the smaller net amount, the effective rate is higher than the sticker rate.
The payment is fixed from the stated rate on the full amount, and n is the number of monthly payments. We solve for i by bisection, then annualize: APR = i × 12.
If you pay no fees at all, the net proceeds equal the loan amount and the APR comes out equal to the stated rate. As fees climb, the gap between the two widens — and on short-term loans, even modest fees can push the APR far above the quoted rate because there are fewer months to spread the cost over.
What raises your APR
- Origination fees — the single biggest driver; a 3% fee on a five-year loan can add more than a full point to the APR.
- Closing and documentation costs — underwriting, packaging, and processing charges all count as loan fees.
- Short terms — the same fee spread over 12 months costs far more per year than over 60 months.
- Points paid up front — discount points lower the rate but count toward APR because they are money out of pocket.
How to use APR when shopping
- Ask every lender for the APR in writing, not just the rate.
- Compare the monthly payment and total cost side by side with the APR.
- If you might repay early, weigh a low-fee loan against a low-APR loan — the low-fee option often wins.
- Check whether your cash flow supports the payment before committing.
Frequently asked questions
What is the difference between APR and interest rate?
The interest rate is the cost of borrowing the principal alone. APR (annual percentage rate) folds in fees such as origination and closing costs, so it reflects the true yearly cost of the loan. APR is always equal to or higher than the stated rate whenever fees are charged.
How is APR calculated?
First the monthly payment is found using the stated rate on the full loan amount. Then the fees are subtracted to get the net proceeds you actually receive. APR is the rate that makes the present value of those same payments equal to the net proceeds, expressed as an annual figure.
Why is my APR higher than the interest rate I was quoted?
Because you repay the loan based on the full amount but only receive the amount after fees. Paying the same monthly payment on a smaller sum you actually pocketed raises the effective yearly cost, which is the APR.
Does a lower APR always mean a cheaper loan?
Usually, but not always. APR assumes you keep the loan for its full term. If you plan to pay off early, a loan with higher fees and lower APR could cost more than a low-fee loan. Always compare total dollars paid alongside APR.
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This calculator is for educational and informational purposes only and does not constitute financial, legal, or lending advice. APR is estimated from the values you enter using standard present-value math and may differ from a lender's disclosed APR, which can include or exclude specific fees under different rules. Confirm all terms with a qualified lender before making decisions.