What happens when the 0% APR period ends
When the 0% introductory period ends, whatever balance is still on the card starts being charged interest at the card’s regular APR. On a true 0% intro APR offer, interest is not charged back to the start, only on the remaining balance going forward. The simplest way to avoid this cost is to pay enough each month to clear the transferred balance, including the fee, before the promo ends.
This guide explains what changes, how deferred-interest offers differ, and how to plan a payment that finishes on time.
What changes on the card
During the promo, interest on the transferred balance is zero, so every dollar you pay reduces the balance. Once the promo ends, the remaining balance is charged the post-promo APR each month. Part of each payment now goes to interest, so the balance falls more slowly, and paying it off takes longer.
Your card’s terms and statements show when the promo ends and what APR applies afterwards. Check both before you transfer, and note the end of the promo somewhere you will see it.
Deferred interest is different
Some promotions, often on store cards, use deferred interest rather than a 0% intro APR. With deferred interest, if the balance is not fully paid by the end of the promo, interest that built up from the start may be charged all at once. A standard 0% intro APR does not work that way. Read the terms carefully to see which type of offer you have. Our calculator models a 0% intro APR, not deferred interest.
Plan a payment that finishes on time
Divide the starting balance on the new card, including the fee, by the number of promo months. Paying at least that much each month clears the balance before interest begins. If that amount is not affordable, pay as much as you can and plan for the remaining balance: know what it will cost at the post-promo APR, and consider whether another option would cost less.
Making only the minimum payment can easily leave most of the balance on the card when the promo ends, because minimum payments may be set well below what it takes to clear a balance in time.
Worked example: finishing on time vs carrying a balance
For example, suppose you move a hypothetical $6,000 balance from a card charging 22% to a card with a 3% fee, a 12-month 0% period, and a 25% APR afterwards. The fee is $180.00, so the new balance starts at $6,180.00. Dividing that by 12 months gives $515.00 a month to clear it during the promo. Using the same math as our calculator:
| Paying $300 a month | Paying $520 a month | |
|---|---|---|
| Balance left when the promo ends | $2,580.00 | $0.00 |
| Interest after the promo | $293.34 | $0.00 |
| Paid off in | 22 months | 12 months |
| Net savings vs staying on the old card | $1,069.51 | $623.19 |
Paying $300 a month leaves $2,580.00 on the card when the promo ends, which then costs $293.34 in interest at 25%. Paying $520 clears the balance inside the promo, so no interest is charged. Both plans save money compared with staying on the old card, but the comparison is against a different baseline: paying more each month would also lower the interest on your old card. What the larger payment really buys here is avoiding the post-promo APR entirely.
Late payments and the promo
Card terms often say that a late or missed payment can end a promotional rate early, and a penalty APR may apply. That can turn a money-saving transfer into a costly one. Setting up automatic payments for at least the minimum, and paying your planned amount on top, can reduce that risk. Our calculator assumes every payment is on time.
If a balance is left
If you reach the end of the promo with a balance, keep paying as much as you can, because the balance is now charged interest. Some people look at another transfer or a fixed-rate loan, but each comes with its own fees and approval decision, and a new transfer fee adds to the cost. Our comparison of a balance transfer and a personal loan shows how to weigh them.
Common questions
Is interest charged on the whole original balance when the promo ends?
Not on a standard 0% intro APR offer. Interest is charged going forward on the balance that remains. Deferred-interest offers are different, so check your terms.
Can I ask for the promo to be extended?
You can ask the issuer, but there is no rule that they must agree. Plan as if the promo will end on schedule.
The takeaway
When the 0% period ends, any remaining balance is charged the card’s regular APR from then on. Paying the starting balance, including the fee, divided by the promo months each month avoids that cost. Watch for deferred-interest offers, pay on time so you keep the promo, and know what a leftover balance would cost.
This guide is educational only and is not financial, tax, or legal advice. The example uses hypothetical numbers; your lender or card issuer sets your actual terms. See how our calculators work.
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