Annual Percentage Rate (APR)

The annual percentage rate is the figure federal law requires a lender to disclose as the cost of consumer credit. Regulation Z, which implements the Truth in Lending Act, states that the annual percentage rate is a measure of the cost of credit, expressed as a yearly rate, that relates the amount and timing of value received by the consumer to the amount and timing of payments made, and that it shall be determined in accordance with either the actuarial method or the United States Rule method. The methods and equations are set out in an appendix to the regulation, which is what makes one lender's figure comparable with another's.

The point of prescribing the method is comparability, and that is also the source of the most common misunderstanding about the figure. An APR is not the interest rate with the fees added on top. It is the single rate that, run through the prescribed equation, reproduces the actual pattern of money received and money repaid over the loan's disclosed term. That distinction changes how the number should be read, and it is worked through below.

What is folded in depends on the kind of credit, and this is where "just compare the APR" quietly stops being good advice. On a closed-end loan such as a mortgage or a car loan, the APR captures interest plus certain financing costs, which is why a mortgage APR is normally higher than the interest rate quoted beside it and why the two figures appearing together is not a contradiction. On a credit card the APR is essentially the periodic rate annualized, and the annual fee sits outside it. Two cards quoting an identical APR can therefore cost very different amounts to hold, and the comparison a cardholder needs is the fee schedule alongside the rate rather than the rate alone.

There is a third thing wearing the same name, and a reader who meets it on a deposit statement should not be surprised. Regulation DD, which governs deposit accounts, defines the interest rate as the annual rate of interest paid on an account which does not reflect compounding, and then permits that figure to be referred to as the annual percentage rate in addition to being called the interest rate. So on a loan the APR sits above the bare interest rate because it adds cost, while on a deposit it may lawfully be the bare nominal rate with compounding stripped out, sitting below the annual percentage yield. The label points in opposite directions on the two sides of a household balance sheet, and carrying it across produces a wrong comparison.

The most useful thing on this page is that Congress built a fourth, deliberately broader annual percentage rate for servicemembers, precisely because the Regulation Z figure leaks. The Military Lending Act's implementing rule caps the military annual percentage rate at 36 percent for covered borrowers, and 32 CFR 232.4(c)(1) sweeps into that calculation any credit insurance premium or fee, any charge for a debt cancellation contract or debt suspension agreement, any fee for a credit-related ancillary product, finance charges, most application fees, and participation fees. Then comes the clause that gives the game away: any such charge shall be included in the calculation of the MAPR even if that charge would be excluded from the finance charge under Regulation Z. A federal regulator wrote down, in a rule, that the ordinary APR omits costs worth capturing. The MAPR is not simply the APR with a ceiling attached; it is a wider measurement, though it keeps its own carve-out for genuine bona fide credit card fees under 232.4(d).

The accuracy tolerances are a disclosure standard, not a pricing allowance. Regulation Z treats a disclosed APR as accurate if it is within one eighth of one percentage point of the properly computed figure, widening to one quarter of one percentage point for an irregular transaction, which the rule defines as one involving multiple advances, irregular payment periods or irregular payment amounts. That is a rule about how precisely the paperwork must match the maths. It does not entitle anyone to charge an eighth of a point more than the deal says.

Because the calculation runs over the disclosed term, an APR describes a loan you keep. Paying discount points lowers the rate, and therefore the APR, by charging money at closing that is then spread across thirty years of disclosed payments. Sell or refinance in year four and the points were paid in full while only a fraction of the benefit arrived, so the APR that looked lower was describing a loan that did not happen. The same logic makes an APR on any short-held loan a poor guide, and it is the reason the break-even calculation below matters more than the comparison of two APRs.

One last boundary. On a mortgage the price-based tests that decide whether a loan is a qualified mortgage, and whether it is a higher-priced or high-cost loan, are keyed to how far its APR sits above the average prime offer rate for a comparable transaction. That machinery lives with the mortgage rules rather than with the definition of the figure, and the thresholds are indexed.

The lender identifies the amount financed and the schedule of payments, including any financing costs the rules require to be treated as part of the finance charge, and solves for the rate that makes the two sides equal under the actuarial method or the United States Rule method. That rate is disclosed as the annual percentage rate. On open-end credit such as a card, the disclosed APR is derived from the periodic rate applied to balances rather than from a payment schedule, because there is no schedule to run.

A hypothetical example of why the APR describes a loan you hold to term. Two offers on the same $300,000 thirty-year mortgage. Offer A is 6.25% with no points. Offer B is 6.00%, bought down by paying one discount point, which is 1% of the loan amount, or $3,000, at closing. Offer B has the lower rate and the lower APR.

The monthly principal-and-interest payment at 6.25% is $1,847.15. At 6.00% it is $1,798.65. Buying the rate down saves $48.50 a month ($1,847.15 − $1,798.65). Dividing the $3,000 cost by that saving gives about 62 months ($3,000 ÷ $48.50 = 61.9), a little over five years, before the point pays for itself.

A borrower who keeps the loan for twenty years is clearly better off with Offer B, and its lower APR says so. A borrower who sells or refinances in year three has paid $3,000 to save about $1,746 ($48.50 × 36), and the lower APR told them nothing about that, because it was computed over a thirty-year term that never happened. The APR is a good comparison figure and a bad forecast, and knowing which one you need is the whole skill.

Pros

• The calculation method is prescribed by regulation, so one lender's figure can be placed beside another's and the comparison means something.
• On closed-end credit it captures financing costs a quoted interest rate leaves out, which is exactly the gap lenders would otherwise compete in.
• It must be disclosed, and the disclosure is enforceable, so it is one of the few numbers in consumer finance a borrower does not have to extract.
• It anchors the price-based tests that regulate higher-priced and high-cost mortgages, so the figure does regulatory work as well as consumer work.

Cons

• It assumes the loan runs its disclosed term, so it misleads about any loan that will be repaid, sold or refinanced early.
• On a credit card it does not capture the annual fee, so the headline figure is an incomplete cost comparison for exactly the product most people compare.
• What counts as a finance charge is a legal question with exclusions, which is why the Military Lending Act had to define a broader figure to reach the same costs.
• The same three letters mean a different kind of number on a deposit account, where they may lawfully label the bare non-compounding rate.
• It says nothing about whether the credit is a good idea, only about what it costs relative to another offer of the same shape.