APR vs Interest Rate

The interest rate is the price the lender charges for the use of the principal, written as an annual percentage. On a fixed-rate loan, the rate is the same each year. On an adjustable-rate loan, the rate can change on a schedule set by the loan contract.

The interest rate drives the basic payment math. On a simple interest setup, the interest charged each year is principal × rate. The simple interest calculator runs that math directly. On an interest only structure, the monthly payment is principal × annual rate ÷ 12; the interest only loan calculator handles those scenarios. On a standard amortizing loan, the interest rate plus the term decides the size of the monthly payment that pays the loan off on schedule.

What the interest rate does not include: fees, points, origination costs, mortgage insurance, or anything the lender charges outside the periodic interest on the balance.

APR stands for annual percentage rate. It is a single annualized cost figure that bundles the interest rate with certain loan costs the lender is required to include under the applicable disclosure rules. Once those costs are folded in, the total is re-expressed as a yearly percentage so that two loans can be compared on one number.

Which costs APR includes depends on the loan type and the disclosure regulations that apply. Items often counted in mortgage APR include discount points, certain origination fees, and some other lender charges. Items that may sit outside APR include third-party fees not retained by the lender, taxes, recording fees, and certain insurance costs. The exact rules vary by jurisdiction and loan category, so always read the actual loan disclosure rather than assuming a list.

Because APR adds costs on top of the interest rate, APR is usually higher than the interest rate on a loan that has any fees. On a no-fee loan, the two numbers can be the same or nearly the same.

Loan amount $250,000, interest rate 7 percent, term 30 years, with $5,000 in loan costs that the disclosure rules include in APR.

• Monthly payment. Based on the interest rate, not APR. Using the standard amortizing formula M = P × r × (1 + r)^n / ((1 + r)^n − 1) with r = 0.07 ÷ 12 and n = 360, the payment is about $1,663.26 per month. That figure is unchanged whether the APR ends up at 7 percent or higher.
• APR. APR spreads the $5,000 of loan costs across the 30 year term and re-expresses the total as a single annualized rate. The math is set by the disclosure regulation rather than a single closed-form formula, and the exact APR depends on which fees are included. With fees in play, the APR ends up modestly higher than 7 percent.
• Takeaway. The interest rate is what runs the payment math. The APR is what summarizes the total cost on one line so two loan offers can be lined up against each other.

The exact APR is the lender's job to compute and disclose. The figures it produces should appear on the written disclosure documents for any loan offer.

The right number depends on what you are doing.

• Estimating the monthly payment. Use the interest rate. The loan calculator and the mortgage calculator both expect the rate, not the APR.
• Comparing two similar loan offers. Use APR as the single-number summary. Two loans with the same interest rate but different fees will show different APRs.
• Understanding the math behind the payment. Read the how to calculate a loan payment guide. It walks through the amortization formula step by step.

APR and interest rate work together. Neither one alone captures the full picture of a loan. The interest rate tells you the payment math; the APR tells you the comparison story.

APR and APY both end in "annual percentage" but they describe different sides of a transaction. APR is commonly used for borrowing costs. APY (annual percentage yield) is commonly used for savings or investment returns and includes the effect of compounding inside the period.

The practical difference is compounding. A 7 percent nominal rate that compounds monthly produces an APY of roughly 7.23 percent, because the interest earned in early months earns its own interest for the rest of the year. On the borrowing side, APR conventions usually do not bake compounding into the headline rate the same way; instead, APR adjusts the rate for fees that come with the loan.

For yield math on a savings account or CD, the APY calculator converts between nominal rate, compounding frequency, and effective annual yield.

• Assuming APR and interest rate are always the same. On a loan with fees they usually are not.
• Comparing APRs across different loan terms without context. A 15 year loan and a 30 year loan with similar fees will not produce comparable APR figures, because the fee spread is across a different number of years.
• Assuming APR always includes every possible cost. APR follows specific disclosure rules and may exclude third-party fees, taxes, recording costs, or some insurance items, depending on jurisdiction and loan type.
• Using APR directly as a monthly payment rate without understanding the lender calculation. Standard payment math uses the interest rate; substituting APR will overstate the payment.
• Ignoring points, origination fees, closing costs, insurance, taxes, and escrow. APR catches some of these but not all of them; the full housing cost on a mortgage is bigger than either the rate or the APR implies.

More background lives in the related guides: how to calculate a loan payment and interest only vs amortizing loan. The rest of the money calculators cover related questions for payments, interest, and savings.