What it means
Credit card interest depends on two things: the rate and the balance the rate is applied to. The adjusted balance method answers the second question in the cardholder's favour by charging interest only on what is still owed when the cycle closes.
The mechanics are direct: take the starting balance, subtract payments and credits posted during the cycle, and apply the periodic rate to the remainder. New purchases may or may not be added, depending on the card agreement.
The contrast methods cost more, because under the average daily balance method, the most common today, interest accrues on each day's balance including new purchases, and under the previous balance method the cardholder pays interest on the opening figure even if most of it was paid off mid-cycle. A simple case shows the gap.
A cardholder starts the month owing $1,000 and pays $900 mid-cycle, so the adjusted balance method charges interest on $100, while the previous balance method charges on the full $1,000 as if the payment never happened. The method matters because card rates are high: with typical purchase APRs (annual percentage rates) in the double digits, the balance definition alone can move a household's annual interest cost by hundreds of dollars on the same spending and payments.
The CFPB's guidance on card interest explains that issuers must disclose which balance computation method they use, and card agreements spell it out, so the method is knowable in advance rather than discovered on the statement. Cards using the adjusted balance method have become rare, since issuers gravitated to average daily balance, which earns more from revolving customers.
For anyone who occasionally carries a balance, the hierarchy is worth remembering: adjusted balance is cheapest, average daily balance sits in the middle, and previous balance is dearest, at identical APRs. For a manager overseeing company cards, the same arithmetic applies to business accounts, so check the computation method in the agreement, because two cards quoting the same rate can bill meaningfully different interest on identical usage.
In practice
Real-world examples.
Example
A cardholder opens the cycle at $2,400 and pays $2,000 on day ten. Under the adjusted balance method she owes interest only on the remaining $400, which at a 1.5% monthly rate is $6. The same cardholder under the previous balance method would be charged on the full $2,400, or $36.
Example
Two cards advertise 24% APR, which is 2% a month. A shopper opens each cycle at $3,000 and pays $2,700 mid-cycle; the adjusted-balance card charges 2% x $300 = $6, while the previous-balance card charges 2% x $3,000 = $60. That is $54 more in a single cycle, or $648 over a year of the same pattern.
Example
A small firm checks its business card agreement and finds the average daily balance method including new purchases. It shifts to paying twice monthly to shrink the balances interest accrues on. The finance manager also adds the computation method to the checklist used when comparing card offers.
Formula
Calculation
Finance charge = periodic rate x adjusted balance, where adjusted balance = opening balance - payments and credits posted during the cycle. At a 1.5% monthly periodic rate, a $1,000 opening balance with a $900 payment gives an adjusted balance of $100, so the charge is 1.5% x $100 = $1.50, versus 1.5% x $1,000 = $15 under the previous balance method.
Now compare all three methods on a $1,200 opening balance, a $1,000 payment halfway through a 30-day cycle, no new purchases and a 1.5% monthly rate. Adjusted balance: $1,200 - $1,000 = $200, and 1.5% x $200 = $3.00. Average daily balance: (15 days x $1,200 + 15 days x $200) / 30 = $21,000 / 30 = $700, and 1.5% x $700 = $10.50. Previous balance: 1.5% x $1,200 = $18.00.Case study
Seen in the real world.
A made-up graduate, Priya, chooses between two cards for a laptop purchase she will clear quickly. This case study is fictional and illustrative. Both quote the same APR, but one uses the adjusted balance method and the other average daily balance including new purchases.
She models her planned payments on a $1,200 balance with $1,000 paid halfway through the cycle at a 1.5% monthly rate. The adjusted-balance card would charge $3.00 and the average daily balance card $10.50, so she picks the first and saves $7.50 in that cycle. The saving is small, but the lesson holds for larger balances: the computation method is worth reading before the card is chosen.
Watch out
Common mistakes.
- Assuming the APR tells the whole cost story; the balance computation method changes what the same rate charges, and card agreements must disclose which method applies.
- Believing mid-cycle payments always cut interest; under the previous balance method they do nothing until the next cycle, which is why the adjusted balance method is the payer's friend.
- Carrying a balance for a grace period; grace applies to new purchases only when the prior balance is paid in full, and revolving any amount can start interest on everything.
Questions
People also ask.
What is the adjusted balance method?
A credit card interest calculation that applies the periodic rate to the balance remaining after payments and credits post in the cycle. It charges the least interest of the common methods for the same APR.
How does it differ from average daily balance?
Average daily balance accrues interest on each day's balance, usually including new purchases, so interest starts immediately on spending. The adjusted balance method charges only on what is left after the cycle's payments, ignoring the timing within the month.
How do you find which method your card uses?
The card agreement's pricing section must disclose the balance computation method, and regulators such as the CFPB explain how the methods work. Cards using the adjusted balance method are now uncommon.
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