What's the Difference Between a Loan's APR and Its Interest Rate?

What the interest rate measures

The interest rate is the percentage cost applied to the loan's outstanding principal to calculate periodic interest charges. It does not include any fees charged separately by the lender, and it is the rate directly used in the loan's amortization schedule to determine the principal-and-interest split of each payment.

What APR adds on top

APR folds most upfront lender fees — such as an origination fee on a personal loan or discount points on a mortgage — into the interest rate, then expresses the combined cost as a single annualized percentage. This is why a loan's APR is always equal to or greater than its stated interest rate. Not every fee is included in the APR calculation, however — some charges, such as a late payment fee or certain third-party fees on a mortgage, are disclosed separately rather than folded into the APR figure.

Why APR is required by law

The federal Truth in Lending Act, implemented through Regulation Z, requires lenders to disclose the APR on consumer loans so that borrowers can compare the cost of different offers on a standardized basis. The Consumer Financial Protection Bureau enforces these disclosure requirements, and lenders are required to disclose the APR prominently, generally in a similar location and format across different loan types, to make offers easier to compare.

How this plays out on a mortgage

On a mortgage, APR incorporates the interest rate plus discount points, mortgage insurance premiums (where applicable), and other closing costs required by the lender, spread over the loan term. Because these upfront costs are amortized differently depending on how long the loan is held, comparing APR alone can understate the cost difference between offers with very different fee structures for a borrower who doesn't hold the loan for its full term — a loan held only a few years absorbs the same upfront fees over a much shorter period than one held to maturity.

A worked comparison of two offers

Consider two $10,000, three-year personal loan offers: Offer A has a 9% interest rate and no fees, producing a 9% APR. Offer B has an 8% interest rate but a $500 origination fee deducted from proceeds, which raises its effective APR above 9% once the fee is factored in, since the borrower receives less than $10,000 up front but still repays interest calculated on the full $10,000. Comparing the two by interest rate alone would suggest Offer B is cheaper; comparing by APR reveals the fee changes that conclusion.

APR on adjustable-rate products

For an adjustable-rate loan, such as an adjustable-rate mortgage, the disclosed APR is calculated using an assumption about how the rate may change after the initial fixed period, based on rules set under Regulation Z. Because the actual future rate on an adjustable product isn't known in advance, the APR disclosed at origination is an estimate built on that assumption, and it can differ from the loan's actual long-run cost if market rates move differently than the assumption used in the disclosure.

APR is not the only figure worth comparing

While APR standardizes most fees into a single rate, some loan-specific factors — such as prepayment terms, whether the rate is fixed or variable, and fees not included in the APR calculation — fall outside the APR figure itself. A complete comparison between loan offers generally involves reviewing the full set of disclosed terms, not the APR figure in isolation.

How APR appears in required disclosures

For mortgages, the APR is disclosed on the Loan Estimate and the Closing Disclosure, two standardized forms required under the TILA-RESPA Integrated Disclosure rule enforced by the CFPB. For other consumer loans, such as personal loans and auto loans, APR is disclosed in the loan agreement itself under the same Truth in Lending Act requirements, though the specific form and format differ from the mortgage-specific disclosures.

APR on auto loans

Auto loan APR disclosure follows the same Truth in Lending Act framework as other consumer loans, incorporating the interest rate along with applicable fees into a single annualized figure. Dealer-arranged financing can include a markup added by the dealer on top of the rate offered by the actual lending institution, which is one reason comparing the dealer's financing APR against a pre-arranged loan offer from a bank or credit union is a commonly described practice before agreeing to dealer financing terms.

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