A few hundred dollars appeared out of nowhere on a card you thought was done. Here is what almost certainly happened, and how to tell whether it is correct.
If a large interest charge posted to your CareCredit account right after you finished paying, the overwhelmingly likely explanation is that the promotional balance was not at exactly $0.00 when the promotional period expired. Not "nearly paid." Not "paid off the week after." Zero, on or before the expiration date.
When that condition is missed, CareCredit releases every dollar of interest that had been quietly accruing since the day of your purchase — not interest on what was left over. That is the mechanic of deferred interest, and it is why the number looks wildly out of proportion to the small balance you had remaining.
During your promotion, interest accrued on the balance every month at the card's standard purchase APR (commonly around 32.99% on CareCredit accounts — check your own agreement, as rates vary and change). You were never billed for it. It accumulated in a reserve behind your statement.
Clear the promotional balance in time and that reserve is waived permanently. Miss it by any amount and the entire reserve posts at once.
You did not get charged interest on $120. You got charged eighteen months of interest on the whole declining schedule, backdated. That asymmetry — a $120 miss producing an $843 charge — is the single most common reason people land on this page convinced something has gone wrong.
Pull up your statements before contacting anyone. You want to know whether this is correct-but-brutal or genuinely wrong.
Real errors do happen: a payment posted late that you can prove was submitted on time, a refund from your provider that should have reduced the promotional balance and did not, or an allocation that contradicts the rule above.
Billing-error disputes are a legal process with a deadline. Under the Fair Credit Billing Act, you generally must send a written dispute that reaches the issuer within 60 days of the first statement containing the error. Call if you like, but put it in writing — written notice is what triggers the legal protections. Include your account number, the specific charge and amount, why you believe it is wrong, and copies (never originals) of proof: payment confirmations, refund receipts, statements.
This is the more common situation, and the honest framing matters: you are asking for discretionary goodwill, not exercising a right. It is granted sometimes, particularly for accounts with clean payment histories, small shortfalls, and a specific reason. Full details, including what to actually say, are in our guide on getting a deferred interest charge waived or reduced.
Two things improve your odds meaningfully: pay the shortfall immediately (bringing the promotional balance to $0 before you ask), and ask for a specific, modest outcome rather than a vague appeal. Partial adjustments are more common than full reversals.
Here is the part that catches people twice. The posted interest is now an ordinary purchase balance, and it accrues interest going forward at the standard APR like any other balance. A charge you leave sitting while you argue about it keeps growing.
Three practical options, roughly in order of cost:
A true 0% intro APR card charges no interest during the intro window and does not backdate anything — unlike the promotion you just came off. If you need several months to clear this, moving it is usually cheaper than carrying it at 32.99%.
Compare balance-transfer options →If you are trying to make sense of any interest charge on a CareCredit statement, it helps to know the account runs two different sets of rules at once:
That split is why "I pay my bill on time every month" and "CareCredit charged me interest" are both true for so many people. On-time payments protect your payment history; only a $0 promotional balance by the deadline protects you from deferred interest. Rates and fees for the account — including the 39.99% penalty APR after two missed minimums and the $30/$41 late fee — are broken down in the CareCredit interest rate guide, and the grace-period mechanics in grace period and late fees.
If you have any other promotional balance open — on this card or a store card from the same issuer — check it tonight. Find each promotional expiration date, divide each promotional balance by the months remaining, and set autopay to that number with a few dollars of buffer. Our CareCredit payment calculator does the arithmetic for you, and how to pay off a promo balance in time walks through the full routine.
Deferred interest is used across dozens of Synchrony-issued store cards, not just CareCredit — see which cards use it. If you have one in a drawer with a promotional purchase on it, that is the next one to check.
Because on-time minimums keep the account current but do not clear a promotional balance by its deadline. Payment history and the deferred-interest condition are two separate tests — you can pass one and fail the other.
Regular purchases: yes, at the standard 32.99% APR, unless you pay the full statement balance within the grace period. Promotional purchases: interest accrues from the purchase date and is only waived if the promo balance hits $0 by the deadline — the grace period does not apply to them.
32.99% standard purchase APR under the current agreement (Synchrony Bank, rev. 3/2026), with a 39.99% penalty APR possible after two or more missed minimums in twelve cycles. Verify against your own agreement — full breakdown in the interest rate guide.
Only for genuine billing errors, in writing, within 60 days of the first statement showing the error (Fair Credit Billing Act). A correct-but-painful charge is a goodwill conversation instead — see getting the charge waived.
No. The balance and posted interest survive closure and keep accruing until paid — and closing the card can raise your credit utilization by removing its limit from the calculation. Pay it down first, then decide about the account.
Related: Getting the Charge Waived · Missing the Deadline · If You Can't Pay It Off in Time · Grace Period and Late Fees · CareCredit Deferred Interest, Explained
Enter each balance and deadline. The calculator shows the monthly payment that keeps the promotion intact — and what a shortfall would cost.
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