The retroactive penalty, exactly how it's calculated, and what to do if your deadline is coming up fast.
A deferred-interest promotion is a quiet countdown. For the whole promotional window — 6, 12, 18, or 24 months — your lender has been calculating interest on your balance every single month and setting it aside in a reserve you never see on your statement. Reach a $0 balance before the deadline and that reserve is wiped out, so you genuinely paid no interest. The instant the deadline passes with any balance remaining, the deal flips.
At that moment the lender takes the entire accrued reserve — every month of interest, backdated to your original purchase date and calculated on the full original purchase amount — and posts it in one lump charge. It does not matter how much you have already paid down; the penalty is the same whether you owe $1 or $1,000 at the cutoff. From that day forward, your remaining balance also begins accruing ongoing interest at the standard APR, which for CareCredit is 32.99% as of 2026 and runs 32.99%–29.99% on most Synchrony store cards.
Say you charged a $4,000 purchase to an 18-month deferred-interest promotion at 32.99% APR and paid it down to $1,200 by the deadline — real progress, but not zero. Here is what posts overnight.
Look closely at what happened. You owed $1,200; overnight you owe $2,606 — more than double — because the interest was calculated against the full $4,000 over the entire 18 months, with the heaviest charges coming from the early months when the balance was largest. The $2,800 you already repaid did nothing to reduce the penalty. That is the part that surprises people: the penalty is based on the original purchase, not on what is left.
The charge usually appears as a single line item labeled "Deferred Interest," "Promotional Interest," or "Accrued Interest — Promotion Expired." It is dated to the close of the billing cycle in which your promotion ended, even though the amount represents months of accrual reaching back to your purchase. This is the first time the reserved interest becomes visible — and it can be a shock. Find that exact line and note the date and amount; you will need both if you call to ask for relief.
The deferred-interest charge itself is not a missed payment, so it does not directly create a derogatory mark. But it can still drag your score down through one mechanism: credit utilization. When the lump charge posts, your balance jumps, and if that pushes the balance closer to your credit limit, your utilization ratio rises. Utilization is one of the largest factors in your score, so a sudden balance spike on a card with a modest limit can cost you points until you pay it back down.
One important distinction: missing the promotional deadline is not the same as missing a payment. As long as you kept making at least the minimum each month, your payment history stays clean even though the promotion expired. You only take a true late-payment hit — the kind that lingers for years — if you also missed the minimum due. Keep paying the minimum no matter what, even in the month the penalty lands.
Sometimes — but go in with realistic expectations. The interest was charged per the terms you agreed to, so the issuer is not obligated to reverse it. That said, a one-time courtesy reversal is a real thing, especially with a clean payment history and a near-miss.
For a CareCredit account, you are calling Synchrony Bank. Here is a practical approach:
Realistic odds: a full reversal is uncommon, a partial credit or short extension more achievable, and your strongest leverage is a spotless payment record. It costs nothing but a phone call, so always ask.
Federal law gives you one protection in the home stretch. Under the Credit CARD Act of 2009, during the final two billing cycles of a deferred-interest promotion, any payment you make above the minimum must be applied to the deferred-interest balance first. Outside that window, issuers can direct extra payments to whichever balance carries the lowest rate, leaving your promotional balance untouched.
So if you carry multiple balances on the same card, your extra payments in those last two cycles are guaranteed to chip away at the balance that actually faces the penalty. Throw everything you can at the card in the final two months — the law is finally on your side.
Sometimes — and the order of operations matters more than people realize. An extension is discretionary: nothing in the promotional terms entitles you to one. But issuers can extend, re-age, or convert a promotional balance, and asking before the expiration date is a fundamentally easier conversation than asking for a reversal after the charge posts. Before the deadline you are a customer trying to stay inside the deal; after it, you are asking the lender to give back money it has already booked.
If your deadline is close and you know you will miss it, call now rather than the day after. Say the promotion ends on [date], you can clear the balance by [a specific, honest date], and ask whether they can extend the promotional period or set up a plan that preserves the waiver. Bring the same assets that help with any goodwill request: a clean payment history and a concrete number. If the answer is no, you have lost nothing — and the fallback options below still work right up to the deadline. If it has already passed, the playbook changes: see getting the charge waived or reduced.
If the cutoff is close and you cannot wipe the balance to zero with cash on hand, you still have moves — each one shrinks or escapes the retroactive penalty before it posts.
Moving the balance to a card with a real 0% intro APR before the deadline converts the one-time backdated-interest penalty into interest-free months to pay it down. A 3–5% transfer fee is usually far cheaper than the deferred interest on a large balance.
See your balance-transfer options →The penalty posted and the balance is bigger than expected. Do not ignore it — at 32.99%–29.99% ongoing, this is among the most expensive debt you can carry, so the priority is to kill it fast.
No — and this is the single most expensive misunderstanding in these promotions. Minimums are set to keep the account current, not to reach $0 by the deadline. The payment that actually protects you is the balance divided by the months remaining. The calculator gives you that number in seconds.
Sometimes, as a courtesy — see the section above. Call before the expiration date, not after, with a specific payoff plan in hand.
The posting date governs, so the charge still lands. But a one-day miss with proof you submitted on time and a clean history is the strongest reversal case there is — call immediately and follow the waiver playbook.
Not as a late payment. The only score effect is the temporary utilization jump from the lump charge, which unwinds as you pay the balance down. You only take a lasting hit if you also miss a minimum payment.
No. A true 0% intro APR simply starts charging interest going forward when the intro ends — nothing is backdated. Deferred interest charges the entire accrued amount retroactively. The full comparison is in Deferred Interest vs. 0% APR.
Related: Deferred Interest Calculator · CareCredit Deferred Interest, Explained · What Happens If You Don't Pay · Grace Period and Late Fees · Charged Interest After Paying It Off · Getting the Charge Waived
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