Balance Transfer Calculator
Find out how much interest you can save by moving high-APR credit card debt to a 0% promotional offer. Accounts for transfer fees, promo period length, and your monthly payment.
Last updated: September 2026
Formula below · 1 source (CFPB) · Updated Sep 2026
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About this calculator
A balance transfer moves existing credit card debt to a new card with a 0% or low promotional APR for a set period, usually for a one-time fee of 3–5% that is added to the transferred balance. This calculator simulates both paths month by month over the promotional period with the same monthly payment: the old card keeps charging its current APR, while the new card starts at balance × (1 + fee) and charges the promotional APR. Savings = (payments + balance still owed on the old card) − (payments + balance still owed on the new card) at the end of the promo, which equals the interest you avoid minus the fee. Any balance left when the promo ends starts accruing the new card's regular APR, so the best result comes from clearing the balance inside the window. A negative result means the fee costs more than the interest you would avoid.
How to use
Say you have a $5,000 balance at 22% APR. A new card offers 0% for 15 months with a 3% fee, and you will pay $350 a month. Old card: 15 payments of $350 ($5,250) still leave about $586 owed, a total of about $5,836. New card: the balance starts at $5,150 including the $150 fee, and $350 a month clears it within the 15 months, costing $5,150. Savings = $5,836 − $5,150 ≈ $686. With the default inputs ($8,500 at 22.99%, 18 months at 0%, 3% fee, $250 a month) the transfer saves about $2,393.
Frequently asked questions
How do I know if a balance transfer will actually save me money?
A balance transfer saves money when the interest you avoid on your current card exceeds the one-time transfer fee plus any interest charged at the promotional rate. Use this calculator to compare both scenarios with your real numbers. Pay special attention to whether you can realistically pay off the transferred balance before the promotional period ends — any remaining balance after the promo typically reverts to a standard APR that can be 20% or higher, potentially wiping out your savings.
What happens if I don't pay off a balance transfer before the promotional period ends?
Once the promotional period expires, the remaining balance begins accruing interest at the card's standard go-to APR, which is often between 18% and 29%. Some issuers also apply deferred interest, meaning if any promotional balance remains unpaid, they charge interest retroactively to the original transfer date. Always read the card's terms carefully to determine which type of promotion applies. Plan your monthly payments so the balance reaches zero at least one month before the promo period closes.
Is a balance transfer fee worth paying if the promotional APR is 0%?
In most cases, yes — the math strongly favors transferring high-interest balances to a 0% card even with a 3–5% fee. A 3% fee on $5,000 is $150, while a single year of 20% APR interest on the same balance is roughly $1,000. The fee is worth paying as long as you commit to paying down the balance aggressively during the promo window. The strategy fails if you accumulate new charges on either card, so discipline is essential alongside the transfer.