What Happens If You Miss the Deadline

The Short Answer

If a deferred-interest promotion ends and you still owe anything — even one dollar — the lender charges you every month of interest that accrued during the entire promotional period, all at once. It is retroactive, calculated back to your original purchase date, on the full original balance. It appears as a single lump charge on your next statement and then begins accruing ongoing interest at the standard APR.

How the Penalty Is Calculated

The lender tracks the interest your balance would have generated each month at the standard APR. Because early months had the highest balance, they generate the most interest. When the deadline passes with a balance remaining, the full accrued total is posted.

What to Do If Your Deadline Is Close

If you can pay it off — do it now

Pay the balance to exactly $0 before the deadline, and confirm the payment posts in time (not just that it's scheduled). Bank transfers can take a few business days. Pay at least several days early.

If you can almost pay it off

It is almost always worth borrowing the last bit — from savings, a 0% card, or even a low-rate personal loan — to get to $0. The penalty on a large original balance usually dwarfs the cost of covering a small remaining amount.

If you can't pay it off

• Balance transfer to a true 0% APR card before the deadline. The transfer fee (typically 3–5%) is normally far less than the deferred-interest penalty.
• Call your lender and ask about your options. Some issuers will, in limited circumstances, re-age or extend an account. There's no guarantee, but it costs nothing to ask.
• Prioritize this balance over lower-rate debts. At 26–30% ongoing, a remaining deferred-interest balance is among the most expensive debt you can carry.

How to Never Be Here Again

The entire trap is avoidable with one habit: from day one, pay the required monthly amount (balance ÷ promo months), not the minimum, and set a reminder 30 days before the deadline. Run your numbers through the calculator so you know the exact payment that gets you to $0 in time.

Related: How to Pay Off a Promo Balance in Time · What Is Deferred Interest?