0% intro APR on purchases vs deferred interest: know the difference

A 0% intro APR and a deferred interest promotion both let you buy something now and pay no interest for a while. The difference shows up at the end: with a 0% intro APR, interest starts only on whatever balance is left, while with deferred interest, missing the deadline by even a small amount can trigger interest on the whole purchase, back to the day you bought it.

That one difference can turn a small leftover balance into a bill of hundreds of dollars.

Two promotions that look the same

The CFPB's 2017 letters to retail card companies described the 0% approach as the less risky option. Under it, "interest is not charged retroactively if the balance is not paid off by the end of the promotional period."

How deferred interest works

The CFPB explains it plainly: if you were told you won't owe interest on a purchase paid in full within 12 months, your card has a deferred interest plan. Pay the full purchase off in time and you owe no interest. If you don't, or if you are more than 60 days late on a minimum payment before the period ends, you can be charged interest on the balance you owed each month since the purchase.

The CFPB has said the retroactive interest is calculated and compounded on daily balances going back to the original purchase amount, not just the balance you have left.

What the CFPB has found

The CFPB has studied these promotions for years. A few findings stand out:

• Many people pay retroactive interest. Citing its 2021 market report, the CFPB says about one fifth of deferred interest promotional balances were charged retroactive interest.
• The rates behind the promotions are high. In its spotlight on retail credit cards, the CFPB reports that over 90% of retail cards had a maximum purchase APR above 30%, compared with 38% of general purpose cards.
• People who miss the deadline often could have paid. In 2017, the CFPB said many consumers who missed the deadline paid off the remaining balance and the charges shortly afterward, which suggests the charges caught them by surprise.
• Terms are not always clear. Consumers told the CFPB that statements and online accounts often did not show how much they needed to pay to avoid deferred interest, and that payments were not always applied to the promotional balance as they expected.

The math: same purchase, two endings

Here is an example with round numbers, not any real card's terms. You buy a $1,200 TV with a 12-month promotion, and the card's standard APR is 30%. You pay $90 a month. After 12 months you have paid $1,080, so $120 is left.

With a 0% intro APR: You owe $120, and interest starts on that $120 from now on. At 30% APR, that is about $3 a month until you pay it off.

With deferred interest: You can be charged interest on the balance you carried each month since the purchase, starting from $1,200. A rough monthly estimate is about $210 in interest, added to your bill at once, on top of the $120. Daily compounding would push the real figure a little higher.

The CFPB's own example is starker. A $4,500 furniture purchase on a two-year deferred interest promotion, with $180 left at the end and an assumed 31.99% APR, leads to an estimated $1,439.55 deferred interest charge.

Why the minimum payment can trap you

The CFPB warns that the minimum payment due alone may not be enough to pay off the balance by the end of the period. On a deferred interest plan, that gap is exactly what triggers the retroactive charge.

Payment allocation adds a second trap. Under Regulation Z, if your card carries several balances, payments above the minimum generally go to the highest-rate balance first, and during most of the promotion a deferred interest balance is treated as having a 0% rate. Only in the last two billing cycles before the promotion expires must extra payments go to the deferred interest balance first. If you put other purchases on the same store card, your extra payments may have been going to those instead.

How to use deferred interest safely, if at all

The CFPB's own tips, plus the math:

1. Find the exact end date. The CFPB notes it can differ from your regular payment due date and is shown on the front of your bill.
2. Divide the purchase by one month fewer than the promo. For a $1,200 purchase on a 12-month plan, aim for $110 a month, not $100.
3. Pay more than the minimum every month, by autopay.
4. Ask the issuer to apply extra payments to the deferred balance. It may say no, but if it agrees, that helps.
5. Never pay late. A minimum payment more than 60 days late can cost you all the deferred interest.
6. Don't add other purchases to the same store card while the promotion runs.
7. Pay it off early. The CFPB suggests finishing well before the period ends, in case a payment is delayed or forgotten.

If you can't comfortably pay the full amount within the promotion, a deferred interest plan is the wrong tool for you.

When a 0% intro APR card is the better choice

For a large planned purchase, a general purpose card with a 0% intro APR on purchases gives you the same no-interest window without the retroactive cliff. If you fall short, you pay interest only on what is left. Our guide to how balance transfer cards work covers how intro periods and standard APRs behave, and card basics explains APR and grace periods.

A 0% card has its own costs. It usually needs good credit to qualify, the application adds a hard inquiry, and the standard APR after the promo can still be high.

Bottom line

"0% intro APR" and "no interest if paid in full" are not the same deal. With a 0% intro APR, missing the deadline costs you interest on what is left. With deferred interest, it can cost you interest on the whole purchase back to day one. If you take a deferred interest offer, plan to clear it at least a month early and never rely on the minimum payment.