Balance transfer calculator

See whether moving a card balance to a 0% promo card saves money after the transfer fee — and get the monthly payment you need to clear it before the promo rate ends.

How the math works

A balance transfer is two numbers fighting each other: a fee you pay today, and the interest you skip while the promo rate holds. The fee comes first. It is a percentage of the balance you move, and it is normally added to that balance, so you start the new card owing more than you did on the old one.

From there the calculator pays that starting balance down month by month. For the promo window it charges the promo rate — usually 0%, which means every dollar of the payment goes to principal. The moment the window ends, any balance still owed starts accruing at the go-to APR, which is the card's ordinary rate and is often as high as the card you left.

To find the payment that clears the balance inside the window, the calculator solves the level-payment amortization formula for the promo months. At a 0% promo it collapses to simple division.

The comparison mode runs the same payment against your current card at its APR and subtracts. What the transfer saves is the interest you would have paid staying put, minus the fee and any go-to-APR interest on a balance that outlived the promo.

Worked example

Take a card balance of $6,500 at the U.S. average credit card APR of 22.76%. A new card offers 0% for 18 months with a 3% transfer fee. The fee is $195, so you start the new card at $6,695.

To clear that inside the 18 months, you pay $6,695 ÷ 18 = $372 a month. Do that and the entire cost of the move is the $195 fee — no interest at all. Put the same $372 a month against the old card at 22.76% instead and it takes 22 months and $1,472 in interest. The transfer saves about $1,277.

Now the version the 0% headline hides. Pay $300 a month instead of $372 — a number that feels close enough. It isn't. When the promo ends at month 18 you still owe $1,295, and that balance immediately starts accruing at the 22.76% go-to rate. You finish in month 23 having paid $70 in interest the 0% rate was supposed to spare you. The gap between $300 and $372 is what turned a free loan into a charged one.

When this calculator is wrong

The arithmetic here is honest about the fee and the leftover balance. What it can't see is how the card behaves once you are living on it, and that is where most of the cost hides.

• New purchases usually don't get the 0%. Carrying a transferred balance means the card is charging interest, so it loses its grace period: anything you buy on that card typically accrues interest from the purchase date until the entire statement balance — transfer included — is paid off. The 0% only ever covered the balance you moved. Use the card for spending and you've quietly reintroduced the interest you transferred away from.
• It assumes you make the window. The whole case for a transfer is the interest you skip, and you only skip it if the balance is gone before the go-to APR arrives. Miss the required payment and the leftover accrues at a rate often as high as the 22.76% card you left. The fee, meanwhile, was charged either way.
• It assumes you qualify for the full term and the quoted fee. The longest 0% windows run to about 21 months and go to the best credit profiles; a thinner file gets a shorter promo or a higher go-to rate. Transfer fees run the whole 3% to 5% range, and a 5% fee on the same $6,500 is $325, not $195.
• It treats the paid-off card as staying at zero. A transfer empties the old card without closing it. If the balance rebuilds there, you now carry the transfer card and the old one — the same failure mode that sinks debt consolidation.

What to do with the result

Switch to the "payment to clear in time" mode and treat that number as the real cost of entry. If you can commit to it, a transfer onto a genuine 0% card is one of the few moves that legitimately beats a high-rate balance — the fee is a known, one-time cost and the interest you skip is larger. Set the payment to clear a month or two before the window closes, so a late statement doesn't tip you into the go-to rate.

If you can't hit the required payment, the transfer still helps, but run the comparison mode honestly: the leftover balance at the go-to APR is the part that decides whether the fee was worth it. And if the real problem is that spending keeps refilling the card, a transfer moves the balance without fixing the leak — the avalanche order on what you already owe, with no new card, is the cheaper fight.

Common questions

Is a balance transfer worth the fee?

When you clear the balance inside the promo window, almost always. A 3% fee on a balance you'd otherwise carry at the 22.76% average APR is small next to the interest you skip. The fee stops being worth it when the promo window is short, the balance is large relative to what you can pay, or the go-to APR catches a big leftover.

What monthly payment do I need to pay it off before the 0% ends?

At a 0% promo, divide the balance plus the fee by the number of promo months. A $6,500 balance with a 3% fee is $6,695; over an 18-month window that's about $372 a month. Pay less and whatever remains at month 18 starts accruing at the go-to APR.

Do new purchases get the 0% rate too?

Usually not. A card carrying a transferred balance is already charging interest, so it loses its grace period, and new purchases typically accrue interest from the day you make them until the whole statement balance is cleared. Unless the offer explicitly includes 0% on purchases, keep spending off the transfer card.

Does a balance transfer hurt your credit score?

Short term, a little. The new card is a hard inquiry and lowers your average account age. Over a longer stretch it often helps, because paying down a balance lowers your credit utilization — provided you don't run the old card back up.

What's the difference between a balance transfer and a consolidation loan?

A balance transfer moves card debt onto another card, usually at 0% for a fixed window, with a transfer fee. A consolidation loan is a fixed-rate installment loan with a set payoff date and an origination fee. The transfer suits a balance you can clear before the promo ends; the loan suits a longer, steady payoff.