How Do Balance Transfers Work?

A balance transfer offer reads like a gift: move your balance, pay 0% for a year or more. What the offer is actually selling is time — a window in which every dollar you pay goes to the debt itself instead of being split with interest. The price of that window is the transfer fee, and whether the trade is worth it is not a matter of opinion. It is a race between two numbers you can compute before you move anything: the fee you pay once, up front, and the interest you stop paying, month by month. This page runs that race on a $5,000 balance at the national average APR, shows the exact month the fee is recovered, and then shows the cases where the fee wins the race instead.

What a balance transfer actually is

A balance transfer moves an outstanding balance from one credit card to another. The new card pays off the old one; you then owe the new card, on the new card's terms. Issuers compete for these moves with promotional offers — a low APR, often 0%, that applies to the transferred balance for a limited period. Three mechanics decide what the move really costs, and all three are in the offer's fine print rather than its headline.

The fee. The Consumer Financial Protection Bureau is blunt about the first one: a card company is permitted to charge a balance transfer fee on a zero percent rate offer — 0% is a rate, not a promise of free. The fee is usually charged as a percentage of the amount you transfer, or as a fixed amount, whichever is more. It is charged once, at the move, and in the examples below it is added to the balance on the new card: transfer $5,000 at a 3% fee and the debt you start paying down is $5,150, not $5,000.

The window. The promotional rate lasts for a limited time — 12 months in the example on this page. While it lasts, the transferred balance accrues no interest (at a 0% offer), so a payment of $300 reduces the debt by the full $300. The CFPB notes the promotional rate is temporary by design: when it ends, the rate on the new card may rise.

The go-to rate. Whatever is still owing when the window closes is charged the card's regular APR — the go-to rate — from that day forward. The leftover is where the second, quieter cost of a transfer hides, and it is why the payment size matters as much as the fee. How regular card interest builds up day by day is covered in how credit card interest is calculated.

The rate, the offer and the rules behind every number on this page

The current card in every example carries the national average rate: 22.36% APR, the average rate on credit card accounts assessed interest in the Federal Reserve's G.19 consumer credit release (data for August 2026, released October 7, 2026). The example offer is 0% APR for 12 months with a 3% transfer fee; a 5% fee is run alongside it because both levels appear in real offers. After the window, the new card's go-to APR is taken as 22.36% as well — the same average — so that no path gains an unearned advantage; your own offer's go-to rate is printed in its terms and may be higher or lower, and judging it against the average is the subject of what is a good APR for a credit card.

Every path is paid with the same fixed monthly payment, so the comparison isolates the transfer itself and nothing else. The simulations assume no new purchases on either card, no fees other than the transfer fee, every payment on time, and both APRs held constant, using the monthly form of the daily interest method. Our full methodology is on how we calculate.

The worked example: $5,000, three ways

Here is the same $5,000 balance, paid at a fixed $300 a month, on all three paths. The payment never changes — only the rate structure around it does.

Read the stay row first. At $300 a month, the interest meter runs for 21 months and collects $1,043.11 — more than a fifth of the original balance, paid for nothing but the passage of time. That is the cost the transfer has to beat, and it sets the scale for everything else: against a four-figure interest bill, the three-figure fee is not the main event.

On the 3% path, twelve payments of $300 land entirely on principal, cutting $5,150 to $1,550. The window closes on that leftover, which then takes six more months at 22.36% and adds $95.60 of interest — the total cost of the whole operation is $245.60, a saving of $797.51 against staying, and the debt ends three months sooner. The 5% path lands in the same shape: a $250 fee, a $1,650 leftover, $107.32 of trailing interest, $357.32 in total — $685.79 saved. The higher fee costs $111.72 more than the lower one, but it does not flip the verdict. At this balance and this payment, the fee was never the deciding factor. The payment is — as the next two sections show from opposite directions.

Break-even: the fee is covered in month two

"Is the fee worth it?" has a precise answer: the month in which the interest you have avoided catches up with the fee you paid. During the 0% window you pay no interest at all, so the avoided interest is simply what the stay path charges, month by month, on its way to $1,043.11.

The very first month at 22.36% costs $93.17 — nearly two-thirds of the fee, gone in thirty days. By the end of month two the stay path has charged $182.48, past the $150 fee: from that point on, the transfer is ahead, and every remaining month of the window widens the lead. Notice what drives the speed of this break-even: it is the APR and the balance, not the payment. A larger balance or a higher rate makes the fee cheaper by comparison, faster. A smaller balance stretches the break-even out — which is exactly where the losing cases at the end of this page come from.

The window is the real deadline

Break-even is the easy half of the math. The harder half is the calendar: the window closes on a fixed date, whether the balance is ready or not. To clear the transferred balance inside a 12-month window, the payment has to divide the whole opening balance by twelve: $429.17 a month at a 3% fee — call it $430 — or $437.50 at 5%. Every dollar a month below that line leaves roughly twelve dollars owing on the day the rate switches back on.

The main example pays $300, which is why it closes with $1,550 still owing and pays $95.60 for the privilege of finishing at the regular rate. That is still a clear win. But watch what happens as the payment shrinks further, to $200 a month. Staying put costs $1,792.96 over 34 months. Transferring at 3% still wins — $606.61 in total, $1,186.35 saved — yet the window closes with $2,750 still on the card, and clearing that leftover at 22.36% takes 17 more months and $456.61 of interest. The same transfer, at the slower payment, costs $361.01 more than it did at $300 a month. A transfer buys time at 0%; only the payment converts that time into savings. Whatever the window fails to finish, the go-to rate meters at full price.

The extreme version of the same point: if the alternative to transferring is paying only the minimum, the stay path on $5,000 runs 231 months — over nineteen years — and costs $8,241.21 in interest, under the minimum-payment model used across this site. Against that baseline the fee is a rounding error. The minimum-payment trap is measured in full in how long to pay off credit card debt; the transfer question only becomes close when the stay path is already a disciplined, fixed payment.

When a transfer loses money

The math above has a losing side, and it is not rare or exotic. A transfer loses whenever the interest it avoids is smaller than the fee it charges — and three ordinary situations produce exactly that result.

You would have cleared the balance almost immediately anyway. The fee is charged in full on day one; the interest it replaces accrues gradually. Pay $5,000 off at the end of one month and the total interest at 22.36% is $93.17 — less than the $150 fee, so the transfer costs $56.83 more than staying. Even clearing it by the end of month two leaves total interest at $141.49, still short of the fee. The faster your existing payoff plan already is, the less interest there is for a transfer to save, and below roughly a two-month horizon a 3% fee cannot pay for itself at this balance. Smaller balances tilt the same way, faster — and because the fee can carry a fixed minimum amount (the CFPB's "whichever is more"), a small transfer can pay a fee that is proportionally larger than the headline percentage.

You spend on the new card. The CFPB warns that if you use the same card for new purchases, those purchases get no grace period: they accrue interest from the day you make them, and keep accruing until the entire balance — including the transferred balance — is paid in full. A card carrying a promotional balance is a card to pay down, not a card to spend on; new purchases quietly reopen the interest meter the transfer was bought to close.

A payment goes badly wrong. Per the CFPB, if you are more than 60 days late on a payment, the card company can increase the interest rate on all balances — including the transferred balance the promotion was supposed to protect. One serious slip can end the 0% deal early and leave the whole debt at a penalty-level rate. And a quieter version of the same risk: if the new card's go-to APR is higher than the rate on the card you left, then any balance the window fails to finish is metered afterwards at a worse rate than it was before the move.

What these numbers leave out

Three real-world wrinkles sit outside the tables. First, the go-to rate: this page charges the leftover at the same 22.36% average on both cards, but a real offer's regular APR is set by the issuer and your credit profile — a higher go-to makes leftovers more expensive, and most card APRs are variable, moving when the Federal Reserve moves its target rate, which is the subject of the Fed and your wallet. Second, the credit limit: the new card may not offer a limit high enough to hold the whole $5,000, and a partial transfer splits the debt — part at the promotional rate, part still at the old rate, across two bills. Third, no two offers are built alike: fee levels, window lengths and rules differ by issuer, which is why the example on this page is labeled with its exact terms rather than presented as a typical offer. The structure, though, does not change: a fee paid once, interest avoided month by month, and a deadline. Any real offer can be priced with the same three numbers. How those numbers get weighed as part of a wider payoff plan is the subject of our Credit Card Debt hub.