Balance Transfer Calculator (0% intro APR vs staying put)

Understanding the balance transfer calculator — concept and principle

This calculator compares keeping a credit card balance on your current card with moving it to a new card with an intro APR and a transfer fee. Paying the same fixed amount each month, it shows the interest on each path, the fee, the net saving, the months to pay off, the balance left when the intro period ends and the payment that would clear the balance within the intro period. Use it before applying for a balance transfer card.

The 3% fee is the price of 18 interest-free months; here it saves about $1,419.

How it is calculated

Both cards are simulated month by month with the same payment:

Interest = balance × APR ÷ 12; then the payment is subtracted, until the balance reaches zero (the last payment is smaller).
New card: the transfer fee (% × amount moved) is added to the balance on day one; the intro APR applies for the intro months, then the regular APR.
Saving = interest on the old card − (interest on the new card + transfer fee).
Payment that clears it in the intro period = (balance + fee) ÷ intro months, when the intro APR is 0%.

The principle

Credit card interest is charged on the remaining balance, so a high APR makes every month you carry the debt expensive. A 0% intro rate stops interest growing, so the whole payment goes to principal. The trade-off is the up-front fee and the risk that a balance remains when the intro period ends and a high regular APR starts. The key number is whether your payment clears the transferred balance before the intro rate expires.

Worked example

Default inputs: balance $6,000, current APR 22.9%, payment $300 a month, fee 3%, intro APR 0% for 18 months, then 24.9%.

Stay: interest totals $1,629.87 over 26 months.
Transfer: fee = 3% × 6,000 = $180, so the new balance is $6,180.
After 18 months at 0%: 6,180 − 18 × 300 = $780 left; it then takes 3 more months at 24.9%, adding $30.77 interest (21 months in total).
Saving = 1,629.87 − (30.77 + 180) = $1,419.10.
Paying (6,180 ÷ 18) ≈ $343.33 a month would clear it within the intro period.

Each point is the calculator re-run with only “Balance to move” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Balance to move	Interest and fees saved
1,500	$47.06
3,000	$270.95
4,500	$717.12
6,000	$1,419.10
7,500	$2,327.94
9,000	$3,535.44
12,000	$7,879.31

How to read the result

A large positive saving means the transfer is worthwhile if you keep paying as planned and do not add new purchases. Check the balance left when the intro period ends: paying a bit more each month to bring it to zero avoids the regular APR entirely.

Common mistakes

Ignoring the transfer fee.
Making new purchases on the card, which may be charged at a higher rate.
Paying only the minimum and leaving a large balance at the end of the intro period.
Missing a payment, which can cancel the intro rate under some card terms.

Keep in mind: Card issuers usually charge interest daily, and their terms differ. Read the card's rate and fee disclosures. This is an estimate, not financial advice.

Frequently asked questions

Is a balance transfer worth the fee?

Usually, when the interest saved is larger than the fee and you can pay off most of the balance during the intro period.

What happens when the intro period ends?

Any remaining balance starts accruing interest at the card's regular APR.

Can I transfer a balance between cards from the same bank?

Usually not; issuers generally do not allow transfers between their own cards.

Sources: Consumer Financial Protection Bureau, "What is a balance transfer fee?" (Ask CFPB) · Regulation Z, 12 CFR § 1026.60

Checked 9 Nov 2026. Monthly amortization of a revolving balance (interest = balance × APR ÷ 12). Balance transfer fees and intro rates: Consumer Financial Protection Bureau, “What is a balance transfer fee?” (Ask CFPB) and Regulation Z, 12 CFR §1026.60 (fees and rates must be disclosed in the card’s rate table).

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