Credit Card Balance Transfer Calculator
Thinking of switching cards to save on interest? Calculate the payback period and see if the transfer fee is actually worth the savings.
What a balance transfer really costs
A balance transfer swaps an interest charge you pay every month for a fee you pay once. On an illustrative $7,500 balance at 24 percent APR, the old card charges about $150 of interest in the first month. A transfer with an illustrative 3 percent fee costs $225 up front, so the fee is recovered in under two months of avoided interest, provided the transferred balance is actually paid off during the promotion.
The CFPB describes the fee as usually a percentage of the amount transferred or a fixed dollar amount, whichever is more, and notes that the promotional rate on most transfers lasts only a limited time, in its credit card key terms (checked October 2026). The fee percentage, promotion length and the rate after the promotion all come from the offer you receive. Every rate and fee on this page is an illustration.
To use the calculator for a transfer, run it twice. First enter your current balance and APR with the payment you plan to make: that is the stay-put cost. Then enter the balance plus the fee at 0 percent with the same payment: that shows whether the total clears before the promotion ends. The difference between the two interest figures, minus the fee, is the saving.
Compare staying with transferring
The 24 percent APR, the 3 and 5 percent fees and the 15-month promotion are illustrations, not offers. The transfer presets add the fee to the balance because most issuers post it to the new card.
Worked Example: $7,500 Moved to a 15-Month 0% Offer
Inputs: a **$7,500** balance at an illustrative **24% APR**, an illustrative **3% transfer fee**, an illustrative **15-month** 0% promotion, and no new purchases on either card.
Fee, promotion length and the payment you need
The monthly payment required to clear a transfer is the balance plus the fee, divided by the promotional months. This table uses the same illustrative $7,500 balance. Longer promotions lower the required payment far more than a smaller fee does.
| Promotion length | 3% fee ($225): payment | 5% fee ($375): payment |
|---|---|---|
| 12 months | $643.75 | $656.25 |
| 15 months | $515.00 | $525.00 |
| 18 months | $429.17 | $437.50 |
| 21 months | $367.86 | $375.00 |
Even at the 5 percent fee, the transfer still wins in this example: paying $525 a month on the old 24 percent card costs $1,420.43 of interest over 17 months, against a $375 fee. The fee matters less than whether you can sustain the payment in the row you pick.
What happens if you fall short
Suppose the plan slips and only $375 a month goes to the 3 percent transfer. After 15 months, $5,625 has been paid and $2,100 remains. If the card then charges an illustrative 24 percent on that leftover and you keep paying $375, it takes 6 more months and about $149.39 of interest. Total cost: $225 fee plus $149.39, or $374.39. Staying on the old card at $375 a month would have cost $2,173.44 of interest over 26 months. A standard 0 percent transfer forgives a shortfall reasonably well, because the CFPB notes interest on the remaining balance starts only from the date the promotion ends (CFPB on promotional financing, checked October 2026).
Deferred interest is a different product
Do not confuse a 0 percent transfer with a "no interest if paid in full" deal, which is common on store cards for purchases. With deferred interest, the CFPB explains that if the balance is not paid off within the promotional window, interest is charged from the purchase date, usually calculated on the balance owed in each month, and that being more than 60 days late on a minimum payment can also end the deferral (CFPB on deferred interest, checked October 2026).
As an illustration, a $1,200 deferred-interest purchase paid at $90 a month for 12 months leaves $120 unpaid at the deadline. Back-charging an illustrative 25 percent APR on each month's balance adds roughly $176 at once, more than the $120 that was left. Read the offer terms for the words "deferred" or "if paid in full" before you treat any promotion like the transfer math above.
Where your extra payments go
If you also make purchases on the transfer card, payment allocation matters. Regulation Z requires issuers to apply the amount above the minimum to the highest-APR balance first, with a special rule sending it to a deferred-interest balance in the two billing cycles before that promotion expires (12 CFR 1026.53, checked October 2026). Extra dollars therefore tend to pay down new purchases first, while the minimum alone chips at the promotional balance. Keeping the transfer card free of new spending avoids that problem.
Common balance transfer mistakes
- Forgetting to add the fee to the balance. The payoff target is $7,725, not $7,500, in the example. Dividing the wrong number leaves a small balance when the rate jumps.
- Paying only the minimum during the promotion. Minimums on a 0 percent balance can be small, so most of the transfer is still there when the promotion ends.
- Spending on the old card again. The freed-up credit line invites new charges, and you end up with two balances instead of one.
- Missing a payment. Late payments bring fees and, depending on the agreement, can end promotional terms. Set up autopay for at least the minimum on day one.
- Treating a store-card deferred offer like a transfer. The back-charged interest can exceed what you saved.
Decision rule: transfer or stay?
A transfer is worth it when three things hold. The stay-put interest from the calculator is clearly larger than the fee. You can pay (balance + fee) / promotional months every month without new borrowing. And the offer is a true 0 percent rate on the transferred balance rather than deferred interest. If the required payment is out of reach, pick a longer promotion, accept that some balance will roll to the post-promotion rate, and price that leftover with the calculator before you apply.
If no transfer offer fits, compare a fixed-rate loan using the debt consolidation cost guide, or keep the debt where it is and attack it with a fixed payment; the avalanche vs snowball guide helps when there are several cards. For the plain stay-put plan with no promotion, use the main credit card payoff calculator, and see the minimum payment math guide for why the statement minimum is not a plan. Illustrative figures only; check the offer terms.
Frequently Asked Questions
Is a 3 percent balance transfer fee worth paying?
How do I calculate the monthly payment for a balance transfer?
What happens if I do not pay off the transfer before the promotion ends?
Can I keep using the card I transferred the balance to?
Does a longer promotion beat a lower fee?
About the Balance Transfer Calculator
Compare balance transfer offers: weigh the transfer fee against interest saved to see if the move pays off.
