Credit-card envelopes and store banners love the phrase 0% intro APR. Sometimes it means true zero interest for purchases or balance transfers during a fixed window. Sometimes nearby fine print describes deferred interest instead. Those products are not interchangeable—and both end on a calendar date you must respect.
Pair this guide with Comparing financing offers and How purchase financing works.
Store and medical “same as cash” plans that claw interest back to day one: Deferred-interest promotions.
True 0% intro APR vs deferred interest
Furniture and appliance “same as cash” plans are often deferred interest, not bank-style 0%—compare endings in Same as cash financing.
| True 0% intro APR | Deferred interest (“no interest if paid in full”) | |
|---|---|---|
| During promo | Interest is $0 on eligible balances | Interest often accrues in the background |
| If balance remains at end | Remaining principal starts accruing the regular APR going forward | Accrued interest from day one can post at once |
| Common on | Bank credit cards (purchase or BT promos) | Store cards and some medical/retail plans |
Always read which one you hold. CFPB consumer materials repeatedly flag deferred-interest traps on retail cards.
Anatomy of a bank 0% purchase promo
Typical terms (examples; yours will differ):
- 0% on purchases for 12–21 months
- Regular APR afterward (often 18–28% variable)
- Balance transfer fee (commonly 3–5%) if the promo is for transfers, not purchases
- Penalty APR if you miss a payment
- Hard credit pull to open the account (Hard vs soft credit checks).
Grace periods on new purchases can behave differently once you carry a promo balance—read whether new charges also get 0% or only the transferred amount.
Worked example: 15-month 0% purchase APR
Furniture cash price: $3,000. Card offers 0% on purchases for 15 months, then 22.9% APR. No annual fee. Hard pull to open.
| Payoff plan | Monthly principal | Interest during promo | Interest after promo if slow |
|---|---|---|---|
| Autopay $200 | $200 × 15 = $3,000 | $0 | n/a — finished on time |
| Autopay $150 | $150 × 15 = $2,250 | $0 during promo | ~$750 left × 22.9% going forward |
| Autopay minimum (~$60) | far below payoff pace | $0 during promo | Large residual; expensive |
Required on-time principal pace: $3,000 ÷ 15 = $200/month. Aim for $220 so one late paycheck does not strand a leftover. If you cannot commit $200/month, the “free” promo is not free—it is a delayed high APR. A personal loan with a fixed schedule may be clearer (When to use a personal loan).
Balance-transfer promos
Transferring a $5,000 card balance at 24% APR to a 0% BT for 18 months with a 3% fee ($150) can save interest if you stop new charges on the old cards and pay at least $5,000 ÷ 18 ≈ $278/month (plus the fee, either up front or into the balance—check). Without a payoff plan, the fee buys only temporary relief. Full fee-vs-interest walkthrough: Balance transfer offers. Execution after the transfer posts: Using a balance transfer to pay down debt. Fold BT math into Debt payoff methods.
Where BNPL and store promos fit
Pay-in-4 BNPL is usually fee-based when late, not a long 0% APR window—see Buy now, pay later risks. Full BNPL vs card total-cost compare: BNPL vs credit card. Store “same as cash” banners are often deferred interest. Do not assume the bank-card rules apply at a mattress checkout—side-by-side math is in Store credit cards vs bank cards. Promo math for register 0% pitches: Zero-percent store cards. Carrier “$0 down” phone plans are usually device installments with promo-credit clawbacks, not a bank 0% card; compare them in Phone/carrier installment plans.
Ending-well rules
Promo APR is not the same as an everyday purchase grace period—when the intro ends, interest rules flip unless you pay the statement in full under the normal grace terms. After the promo, pick the long-term card with rewards vs APR math, not the leftover signup bonus.
- Calendar the promo end date the day the account opens.
- Divide principal (+ BT fee if added) by months remaining; autopay that amount.
- Keep one payment buffer (hit $0 30 days early).
- Turn off new charges on the promo card unless they also qualify and you recalculate.
- After the promo, either carry $0 or refinance deliberately—do not discover the regular APR by surprise.
Checklist
- Label the offer: true 0% vs deferred interest; confirm intro length and go-to APR on the Schumer box; know what APR vs interest rate includes when the promo ends.
- Note purchase vs balance-transfer eligibility and fees.
- Confirm soft vs hard pull before applying.
- Write monthly payoff required to hit $0 on time.
- Autopay principal pace; alert for failed payments.
- Compare total cost to cash and to a personal loan.
- Re-read penalty APR and late-fee clauses once (How late fees and penalty APR work).
Store and brand co-branded promos often use deferred interest instead of true 0%—compare Co-branded credit cards and Store credit cards vs bank cards.
Educational only. Not an offer of credit or a recommendation of any card issuer. Promotional terms vary. Read the cardmember agreement before you apply.