Credit card promotional rates work by giving you a temporary window, usually 12 to 21 months, in which interest on certain balances is reduced or waived entirely. After the window closes, the card’s regular APR takes over on whatever is left. Used well, these offers can save hundreds or thousands of dollars. Used carelessly, or on the wrong kind of promotion, they can cost more than carrying the debt on your old card.
What the Promotional Rate Actually Covers
Two different promotional rates can appear on the same card, and they are tracked separately in your agreement.
An introductory purchase APR applies to new things you buy with the card after opening the account. A balance transfer APR applies to existing debt you move onto the card from another lender. You might get 0% on purchases for 15 months and 0% on balance transfers for only 12, or the reverse. The card agreement spells out the length and terms of each.
Cash advances sit outside all of this. If you withdraw cash against your credit line, you’ll pay a separate and higher APR that starts accruing immediately with no grace period, plus a cash advance fee often around 5% of the amount. No introductory offer covers a cash advance.
True 0% APR vs. Deferred Interest
This distinction matters more than any other detail on the offer, and it trips up more consumers than any other feature of promotional rates.
A true 0% introductory APR means no interest accrues on your balance during the promotional period. If a balance remains when the period ends, interest starts running from that point forward on whatever is left.
Deferred interest is different. Interest is accruing the whole time in the background. Pay the balance in full before the deadline and that accrued interest is waived. Leave any balance at all when the period ends and you owe the full accrued amount, calculated back to the original purchase date, as if the promotion never happened.1Consumer Financial Protection Bureau. How to Understand Special Promotional Financing Offers on Credit Cards
An example makes the gap concrete. You buy a $1,000 item on a card with a 12-month promotion at 26% APR. You’ve paid down $900 and $100 remains when the promotion ends. With a true 0% offer, interest now runs on that $100. With deferred interest, you owe the $100 plus roughly $260 in retroactive interest on the original $1,000.1Consumer Financial Protection Bureau. How to Understand Special Promotional Financing Offers on Credit Cards
Deferred interest offers show up most often on store-branded retail cards at furniture stores, electronics retailers, and medical providers. If your offer uses the phrase “no interest if paid in full,” it’s almost certainly deferred interest. Major-issuer offers that say “0% introductory APR” without that conditional language are the true kind.
The Balance Transfer Fee
A 0% balance transfer APR is not the same as a free transfer. Most issuers charge 3% to 5% of the amount moved, often with a minimum of $5, added directly to your new balance the moment the transfer processes. On a $10,000 transfer at 3%, that’s $300 in fee.
The fee sits outside the promotional rate and won’t show up in the APR figure. Run the math before you commit. Transferring a 22% balance you can realistically pay off inside the window still beats staying put. Transferring a balance you can’t pay off in time may end up costing more once the fee and post-promotional interest are counted.
How Long the Rate Lasts and What Can End It Early
Federal rules require any promotional rate to last at least six months.2eCFR. 12 CFR 1026.55 – Limitations on Increasing Annual Percentage Rates, Fees, and Charges Most issuers land between 12 and 21 months. The length is locked in at account opening, and the issuer can’t shorten it on you as long as you meet the terms.
Meeting the terms means making at least the minimum payment on time every month, even while you’re paying 0%. If a payment runs more than 60 days late, the issuer can revoke the promotional rate and impose a penalty APR, commonly around 27% to 30%.3Office of the Law Revision Counsel. 15 USC 1666i-1 – Limits on Interest Rate, Fee, and Finance Charge Increases
A penalty rate isn’t necessarily permanent. If an issuer raises your rate for late payment, it must lower the rate back down after you make six consecutive on-time minimum payments, and it has to tell you about this in the same notice that announced the increase.2eCFR. 12 CFR 1026.55 – Limitations on Increasing Annual Percentage Rates, Fees, and Charges Many cardholders don’t realize the reversal is required and accept the higher rate as final.
What Happens When the Promotion Ends
When the promotional period expires on the date originally disclosed, your card’s standard APR takes over on any remaining balance. The issuer does not have to send you a separate 45-day warning, because you already received the required disclosure when you opened the account.4Consumer Financial Protection Bureau. When Can My Credit Card Company Increase My Interest Rate Put the expiration date on your calendar; no reminder is coming.
Most cards use a variable ongoing APR: the issuer adds a fixed margin to the prime rate, and the sum is your rate. As of early 2026, prime sits at 6.75%.5Consumer Financial Protection Bureau. Credit Card Interest Rate Margins at All-Time High A 15-point margin makes your standard APR 21.75%. Both the margin and the resulting APR appear in your card agreement.
Interest itself accrues daily. The issuer divides your APR by 365 to get a daily periodic rate, then applies that rate to your average daily balance for the billing cycle.6Consumer Financial Protection Bureau. How Does My Credit Card Company Calculate the Amount of Interest I Owe
Residual Interest on Your Next Statement
Even if you pay the full statement balance after your promotional period ends, a small interest charge often appears on the following statement. This is residual, or trailing, interest, and it covers the days between when your statement was generated and when your payment posted. That interest wasn’t billed on the statement you paid, so it lands on the next one. One more payment usually clears it.
How Payments Get Split Between Balances
Once you have balances at different rates on the same card, allocation rules decide which one your payments pay down. Suppose you transferred $5,000 at 0% and later charged $500 in new purchases at 22%.
Any amount you pay above the minimum has to go to the highest-APR balance first, then the next highest, and so on.7Consumer Financial Protection Bureau. 12 CFR 1026.53 – Allocation of Payments That protects you from an issuer routing every payment to the 0% balance while the expensive one keeps accruing.
Deferred interest balances get a specific rule for the endgame. In the last two billing cycles before the deferred interest period expires, any excess payment must be applied to the deferred interest balance first, giving you a better chance to zero it out before retroactive interest hits.7Consumer Financial Protection Bureau. 12 CFR 1026.53 – Allocation of Payments Even so, the safer play is to attack a deferred interest balance well before those final two cycles.
The Grace Period Trap
A credit card grace period is the window between the end of a billing cycle and your due date during which new purchases don’t accrue interest. When a grace period is offered, federal law requires it to be at least 21 days.8Office of the Law Revision Counsel. 15 USC 1637 – Open End Consumer Credit Plans
The trap: if you’re carrying a 0% balance transfer and you also make new purchases on that same card, those new purchases may not get a grace period. Interest can start accruing on them from the day of purchase, even if you pay the statement balance in full each month. The clean fix is to keep the promotional card dedicated to paying down the transferred debt and put everyday spending on a different card.
Who Qualifiesh2>
Promotional offers generally go to applicants with credit scores in the good-to-excellent range. Most issuers look for a FICO of at least 670, and the longest promotional windows tend to be offered to applicants above 740. A higher score doesn’t guarantee approval at the advertised rate, but it improves the odds.
Most offers are also limited to new customers. Issuers typically require that you haven’t held the same card or received its signup bonus within a look-back period whose length depends on the issuer and the product. Applying for a card you recently held is a common way to burn a hard credit inquiry for nothing.
On that inquiry: a new card application knocks a few points off your score and stays on your credit report for two years. The effect fades within a few months for most people. If you’re planning a mortgage or another major loan soon, the timing is worth thinking through before you apply.