Balance transfer calculator

A 0% balance transfer is one of the few genuinely cheap forms of credit available to an ordinary borrower, and one of the easiest to misuse. The offer does not reduce your debt. It pauses the interest on it, for a fixed number of months, in exchange for a fee. What happens in those months decides whether it was a good decision.

The four numbers in every offer

• The promotional APR, usually 0%, and how long it runs. Typically 12 to 21 months.
• The transfer fee, almost always 3% or 5% of the amount moved, added to the balance on day one.
• The go-to APR, which applies to anything still outstanding when the promotion ends. This is a normal card rate and is often above 22%.
• The credit limit you are approved for, which caps how much you can actually move and is not known until after you apply.

The single question that decides it

Can you clear the transferred balance, fee included, before the promotion ends? Divide the total by the number of promotional months. On $7,004 over 18 months that is $390 a month. If you can commit that, the transfer is close to the cheapest debt you will ever carry. If you can only manage $250, then about $2,500 will still be outstanding when the go-to rate arrives, and you have bought yourself eighteen months and a $204 fee rather than a solution.

Two things stand out. The transfer wins at every payment level in this example, the fee is simply much smaller than the interest avoided, and the advantage is largest for the person paying least, which is precisely the person most likely to still be in debt when the window closes. Both facts can be true at once, and it is why the honest advice is neither "always transfer" nor "it is a trap".

How these offers actually go wrong

Paying less because the payment got cheaper

This is the dominant failure mode. Interest stops, the minimum payment drops, and the monthly amount drifts down to match. Eighteen months later the balance is barely moved and the go-to rate arrives. The fix is mechanical: set an automatic payment for the amount that clears the balance in the window, on the day the transfer completes, and do not revisit it.

Spending on the new card

On many transfer cards, purchases sit at the full purchase APR while the transferred balance sits at 0%. Federal rules require payments above the minimum to go to the highest-rate balance first, which protects you, but only above the minimum. Keep the transfer card out of your wallet until the balance is zero.

Spending on the old card

The card you just cleared now has a full credit limit available and no balance. A meaningful number of people transfer $7,000, feel relief, and are carrying $4,000 on the original card within a year. Now with two balances instead of one. If the spending was the problem, the transfer has not addressed it.

Losing the promotional rate

Most issuers reserve the right to end a promotional APR if you pay late. Read the terms; the trigger is usually a payment 60 days past due, but some are stricter. Autopay for at least the minimum removes this risk entirely.

Practical mechanics

• You cannot transfer between cards from the same issuer. Chase to Chase will not work; plan around it before applying.
• Transfers take days to post. Keep paying the old card until you see the balance actually clear, or you will collect a late fee on a card you thought was settled.
• Most cards cap transfers at the credit limit or a fixed amount, and you may be approved for less than you need. Moving the highest-rate portion first is the right partial strategy.
• Applying costs a hard inquiry and lowers your average account age. The effect is small and temporary, but avoid it in the months before a mortgage application.
• Keep the old card open. Closing it reduces your available credit and can raise your utilisation ratio, which is one of the largest inputs to a credit score.