Balance Transfer Calculator

What this comparison is testing

A balance transfer can reduce interest sharply during a promotional window, but the transfer fee and the go-to APR still matter. The useful question is not just whether the promo APR is lower, but whether the combination of fee, promo length, and later rate produces a better all-in payoff path than keeping the debt on the current card.

That is why this calculator fixes the monthly payment in both scenarios. Holding the payment constant makes the comparison cleaner: you can see whether the transfer itself creates a cheaper or faster path, rather than changing both the card and the payment at the same time.

The result now also checks whether the same monthly payment is enough to clear the transferred balance before the promotional APR ends. That matters because many balance-transfer offers look attractive until you compare the required promo payoff payment with what you can actually afford each month.

Core balance-transfer maths

The current-card side uses the entered balance, current APR, and monthly payment to estimate payoff time and total interest. The transfer side applies the entered promo APR for the promo window, switches any remaining balance to the go-to APR after that, and then adds the transfer fee as an extra cost outside the interest stream.

Because the monthly payment is held constant, the monthly-payment change is usually zero in this model. The decision points instead become total interest saved, total repayment difference after the fee, and whether the balance can be cleared before the promo APR expires.

A stronger balance transfer savings calculator should not stop at the final savings number. The fee break-even month helps answer a different question: when do cumulative interest savings first recover the upfront transfer fee?

Worked example: 6,000 at 24.99% with a 0% promo for 15 months

Suppose the current balance is 6,000 at 24.99% APR and the monthly payment is 500. The transfer offer charges a 3% fee, gives 0% promo APR for 15 months, and then reverts to 24.99% if a balance remains.

In this calculator, the current card takes about 14 months and costs about 975.81 in interest. The transfer path clears in about 12 months, incurs essentially no interest during the payoff window, and costs 6,180 all in once the 180 transfer fee is included. Because the balance is cleared before month 15, the go-to APR never applies.

How to tell whether the transfer fee is worth it

A balance transfer fee is usually charged as a percentage of the amount moved, often with a small minimum fee. That fee can still be worth paying if the promo APR lasts long enough to eliminate most or all of the balance before the reversion rate applies.

The most useful comparison is the total repayment difference, not the headline APR alone. A lower promo APR can still be a poor deal if the fee is large, the promo period is short, or the go-to APR is close to the rate on your current card.

The break-even month is useful when two offers look similar. If the calculator says the fee is recovered quickly, the transfer has more room to be worthwhile. If the break-even point is late or never reached, the advertised 0% APR may not offset the fee enough for your payoff plan. Offer presets can help you pressure-test common structures such as a 3% fee with a 15-month promo, a 5% fee with a longer promo, or a no-fee credit-union-style offer.

Promo payoff target and fee break-even

The payment-to-clear-promo figure estimates the monthly payment needed to eliminate the transferred balance during the promotional window. If your entered payment is above that target, the go-to APR is less likely to matter. If it is below the target, the remaining balance after the promo period becomes a major part of the decision.

The fee break-even result compares cumulative interest avoided against the upfront transfer fee. For example, if a 3% fee costs 180 and the current card would have charged more than 180 in interest by month 2, the transfer fee is recovered quickly. If the current APR is low or the payment is high enough to clear the current card soon anyway, the fee may never break even.

What happens when the promo APR ends

If any balance remains when the promotional period ends, the remaining amount switches to the go-to APR entered in the calculator. That is the point where a cheap-looking offer can turn expensive again, especially if the balance is still large and the regular APR is high.

For that reason, it is usually safer to treat the promo window as the deadline for getting the balance as low as possible, not as a bonus period to ignore until later.

What this estimate excludes

This page is deliberately narrower than a full card-comparison engine. It does not model new purchases, missed payments, penalty APRs, different minimum-payment formulas, issuer-specific promo-allocation rules, or cases where the transfer fee is financed into the new balance.

Use it as a planning comparison for one existing balance and one transfer offer. If the real card terms include special purchase APRs, deferred-interest clauses, or promotional conditions tied to payment behavior, check the issuer disclosure before relying on the result.