Balance Transfer Calculator: Is the 0% Promo Worth the Fee?
Enter your card balance, its APR, the transfer fee, and the 0% promo length, plus the monthly payment you can actually make. The calculator compares transferring against staying put and tells you which one wins after the fee.
What you'd move to the new card
The rate your balance pays today
Usually 3-5%, added to the balance up front
0% promo length (months)
The same amount is applied on both paths
Interest avoided during the promo
$1,455
what staying at 24.99% would cost over 1 year 3 months
Transfer fee
$180
3% up front, so you start owing $6,180
Left when the promo ends
$1,680
$412/month would clear it before the rate snaps back
Verdict
Transfer wins by $1,275
interest avoided minus the fee, over the promo window
At $300/month, $1,680 is still on the card when the promo ends. From that month on it accrues interest at the card's regular APR, which is often in the 25-30% range, so the real value of the transfer depends on what happens to that leftover. Staying put at $300/month would leave $2,955 after the same 1 year 3 months.
Fee versus interest: one comparison decides it
A balance transfer trades a recurring cost for a one-time cost. Staying put, your balance accrues interest every month at APR divided by 12. Transferring, you pay a single fee of 3-5% and then nothing during the promo. So the math reduces to: interest you would have paid over the promo window, minus the fee. This calculator simulates both paths with the same monthly payment, which keeps the comparison honest, since paying $300 a month against a 25% APR retires far less principal than paying $300 against 0%.
The example in the defaults
Move $6,000 from a card at 24.99% with a 3% fee and a 15-month promo, paying $300 a month. The fee is $180, so the new card starts at $6,180. Staying put, those same 15 payments of $300 would generate about $1,455 in interest and still leave roughly $2,955 owing. Transferring, you pay zero interest, and the transfer comes out about $1,275 ahead after the fee. The catch: $300 a month clears only $4,500 of the $6,180, so about $1,680 remains when the promo ends. Clearing everything inside the window takes about $412 a month, and that number, not the minimum, is the real price of a clean escape.
The promo cliff is the whole risk
Transfer cards make money on what happens at month 16. Whatever is left starts accruing at the card's regular APR, often higher than the one you left, and new purchases usually lose their grace period while a transferred balance sits on the card. The defense is to treat the promo as a deadline: divide the transferred balance by the promo months, automate that payment, and put the card in a drawer. If the required payment doesn't fit your budget, a fixed-rate loan with a longer runway may fit better; the debt consolidation calculator runs that version of the trade.
Where a transfer fits in a payoff plan
A transfer doesn't reduce debt, it freezes the meter while you pay. It works best as the opening move of a payoff plan you've already committed to, whether that's snowball or avalanche, with spending held flat so the old card stays empty. The credit card payoff calculator shows what your payment achieves at the regular rate, which makes a nice before-and-after for the transfer decision.
Frequently asked questions
How does a balance transfer work?
A new card pays off the balance on your old card, and the debt moves over at a promotional 0% APR for a set window, commonly 12 to 21 months. You pay a one-time transfer fee, usually 3-5% of the amount moved, which is added to the new balance. During the promo, every dollar you pay goes to principal.
Is a 3% balance transfer fee worth it?
Usually, if the balance would otherwise sit at a high APR. On $6,000 at around 25%, interest runs about $125 in the first month alone, while a 3% fee is a one-time $180. The fee roughly equals six weeks of interest, and the promo buys you 12-21 months without any.
What happens when the 0% promo ends?
Any balance still on the card starts accruing interest at the regular APR, which is often 25-30%. Most transfer cards charge interest only from that point forward, but some retail financing offers use deferred interest, which back-charges interest on the whole original amount. Read which kind you're signing.
Do balance transfers hurt your credit score?
Opening the new card adds a hard inquiry and lowers your average account age, which can cause a small dip. But the added credit limit usually lowers your overall utilization, which tends to help. The bigger risk is behavioral: two cards means two places a balance can grow.
Can I keep using the old card after transferring?
You can, and that's the classic way transfers backfire: the old card fills back up while the new one holds the transferred balance, doubling the debt. Many people leave the old account open for credit history but stop carrying it. New purchases on the transfer card can also accrue interest immediately unless purchases have their own 0% offer.
Does this calculator save my numbers?
No. Everything runs in your browser and nothing you type is stored or sent anywhere.
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