How does a balance transfer work, step by step

A balance transfer moves debt from one credit card to a card at a different bank that charges 0% interest for a set number of months. The new issuer pays off the old account, the amount plus a fee lands on the new card, and the interest meter stops for the length of the promotion. Nothing is forgiven. The debt is the same size, slightly larger after the fee, and it is now sitting on a clock.

Step one: applying and getting approved

The promotion belongs to a new account, so a transfer starts with an application and a hard credit inquiry. Approval decides two things that matter more than the headline rate: the credit limit, and whether the applicant qualifies for the long promotional window or a shorter one. Over 99% of promotional rate offers made in 2023 and 2024 were 0% for an initial period of six to 21 months, per the CFPB’s 2025 market report, but the 21-month offers go to the strongest applicants.

The transfer request itself can usually be made during the application, which is the cheapest moment to do it, or afterwards through the account. Either way, the amount that can be moved is capped by the new limit, and the fee counts against that limit as well.

Step two: the transfer window

Issuers only apply the promotional rate and the cheaper introductory fee to transfers requested inside a window that starts at account opening. Miss it and the transfer usually gets the standard fee, often 5%, and frequently no promotional rate at all.

These windows are issuer policy, not law, and they change. The one thing that does not change is that the clock starts at account opening, not at the moment the transfer is requested.

Step three: the fee is added, not deducted

The fee posts at the same time as the transfer, as a one-off charge, and it increases what is owed. It is not netted out of the amount moved. One major issuer’s own illustration is exactly this: transfer $1,000 with a 5% fee and the amount to repay is $1,050.

Market fees run from 3% to 5% of each transfer, with a minimum of $5 on most cards. The CFPB found the average fee charged by the largest 25 issuers was 4.3% in the second half of 2024, up from 3.9% in 2022, with an average minimum fee of $5.51. Two-tier pricing is now the norm: a lower rate for transfers inside the window, a higher one afterwards. The fee applies per transfer, so consolidating four cards means four fees. The fee calculator works through the arithmetic in more detail.

Step four: the promotional clock starts at account opening

This is the part that surprises people. On nearly every US card the 0% period runs from the day the account opens, not the day the transferred balance arrives. If the account opens on the 1st and the transfer posts on the 15th, a 15-month promotion has already spent two weeks of itself on an empty card. The default assumption in the calculator is a 14-day posting lag for that reason.

A handful of cards count promotional cycles from each transfer instead. That is the exception. Assume the account-opening rule unless the card’s own terms say otherwise.

Step five: the old card, until the payoff posts

The old account is not closed by a transfer and it is not silent while the transfer travels. Interest keeps accruing there at the old APR until the payment posts, which typically takes a week to three weeks. Chase says explicitly to keep making payments on the old account until the transferred amount has posted and the balance is paid.

Two things follow. First, a payment due date that falls inside the transfer window still has to be met, or there is a late fee on an account that is about to be emptied. Second, the old card’s final statement will usually carry a small amount of trailing interest, the interest that accrued between the last statement and the day the payoff landed. It is real, it is owed, and an account left at “$0” without checking will quietly go past due over a few dollars. How long a transfer takes covers the issuer-by-issuer timing.

A worked example

Take $5,000 on a card at 22.15%, the Federal Reserve’s Q2 2026 average rate on accounts assessed interest. The new card offers 0% for 18 months with a 3% transfer fee.

Paying $300 a month on the original card at 22.15% would have taken about 21 months and cost roughly $1,100 in interest. The transfer route costs $150 in fees and no interest, provided the $302.94 is actually paid every month. Paying the minimum instead leaves most of the balance intact when the promotion ends, which is the failure mode the minimum payment page covers.

Step six: the promotion ends

At expiry the promotional rate stops applying to whatever is left, and the go-to rate takes over from that point forward. It is not retroactive. This is the difference between a true 0% promotion and a deferred interest offer on a store card, where unpaid interest is calculated the whole time and capitalised if any balance remains. The two are not the same product and the deferred interest explainer sets out why.

Under 12 CFR 1026.55 a promotional rate has to last at least six months, and it can only be revoked early if the minimum payment is more than 60 days late. A payment under 60 days late may trigger a penalty rate on new transactions, but it does not end the promotion on the transferred balance. That protection applies to consumer credit card accounts, not business cards or charge cards.

Same-issuer transfers are refused

Debt cannot be moved between two accounts at the same bank. Chase to Chase, Citi to Citi, Amex to Amex, Capital One to Capital One, including Discover now that it is part of Capital One: all refused. The whole point, from the issuer’s side, is buying a balance away from a competitor. There is no version of the request that gets around this, and applying for a second card at the same bank in the hope of transferring will waste a hard inquiry.

Whether the arithmetic works

A transfer earns its fee when the interest avoided is larger than the fee paid, and when the balance can realistically be cleared inside the promotional window. On a small balance, a short promotion or a high fee, it often cannot. Run the numbers rather than assuming, and see whether a transfer is worth it for the break-even framing.