What the Zero-Percent Balance Transfer Calculator does
This calculator shows whether moving a credit card balance to a 0% or low-rate balance transfer offer really saves money once the transfer fee is paid. It runs the same monthly payment through both options - staying on your current card, or transferring - month by month, and gives the net saving, how much is still owed when the promotional rate ends, and the payment that would clear the balance within the offer.
A balance transfer swaps interest for a one-off fee, typically 3% to 5% of the amount moved. Whether that is a good trade depends on three things people often skip: how big the fee is against the interest you would otherwise pay, whether you can clear the balance before the 0% period ends, and what rate applies to whatever is left. The month-by-month table makes all three visible.
How to use it
- Enter the balance you would move, your current card's APR and the monthly payment you can afford. The same payment is used for both options so the comparison is like for like.
- Enter the offer: the transfer fee as a percentage (and a minimum fee if the card has one), the promotional APR - usually 0 - and how many months it lasts.
- Enter the APR that applies once the offer ends. It is in the card's summary box, often called the standard or revert rate.
- Read the saving at the top, then the warnings. If money is still owed when the offer ends, the page shows how much and the monthly payment that would clear it in time.
- Use the chart and the table to see both balances fall month by month, and download the comparison as CSV.
Reading the results
The saving is the interest you avoid on the current card minus the transfer fee and any interest charged on the new card. A positive figure means the transfer is cheaper at your payment; a negative one means the fee costs more than it saves.
"Owed when the offer ends" is the number to watch. Anything left starts accruing interest at the revert rate, which on many cards is as high as the rate you left. Clearing the balance inside the 0% period is what makes a transfer work.
The "payment to clear in the offer" is the transferred balance including the fee, divided over the promotional months (or the equivalent annuity if the promotional rate is not 0%).
If either option says "never", the payment does not cover the monthly interest at that rate, so the balance would not fall. Raise the payment before comparing.
Worked example: $5,000 at 24% APR, moved to a 15-month 0% offer with a 3% fee, paying $300 a month
Staying: 24% APR is 2% a month. After 20 payments of $300 the balance is 5,000 x 1.02^20 - 300 x (1.02^20 - 1) / 0.02 = $140.53, and a 21st payment of $143.34 clears it. Total paid $6,143.34, of which $1,143.34 is interest.
Transferring: the 3% fee is $150, so the new balance is $5,150. Fifteen interest-free payments of $300 leave $650 when the offer ends.
At 24% from month 16 that $650 takes three more payments - $13.00, $7.26 and $1.41 of interest - so the transfer costs $150 + $21.67 = $171.67.
Net saving: $1,143.34 - $171.67 = $971.67. Paying $343.34 a month instead ($5,150 / 15) would clear it inside the offer and save another $21.67.
Formulas and scoring rules
- Monthly interest
interest_k = balance_(k-1) x APR / 12 / 100Most card issuers apply a daily rate to the average daily balance, so a statement can differ from this monthly model by small amounts.- Balance after a payment
balance_k = balance_(k-1) + interest_k - payment- Transfer fee
fee = max(balance x fee% / 100, minimum fee); new balance = balance + fee- Payment to clear within the offer
payment = new balance / promo months (0%); otherwise new balance x i / (1 - (1 + i)^-m), i = promo APR / 12- Net saving
saving = interest staying - (fee + interest transferring)Figures are not rounded until display; the simulation stops after 600 months.
The traps the headline rate does not show
New purchases on a balance-transfer card are often charged at the standard purchase rate from day one. In the US, Regulation Z requires payments above the minimum to go to the highest-rate balance first, but the minimum payment itself can still go to the 0% balance, so spending on the new card while carrying a transfer can be expensive. Many cards also cancel the promotional rate if a payment is late.
Offers usually apply only to transfers made within a set window after opening the account, and you generally cannot move a balance between two cards from the same bank. The fee is charged when the transfer is made, so a transfer you later regret still costs the fee. Check these terms in the card's summary box before you apply.
Limitations: what the result does not prove
- It models one fixed payment and no new spending, cash withdrawals or late payments on either card.
- Interest is computed monthly on the balance; issuers compute daily, and some charge interest on the fee from a different date. Expect small differences from a real statement.
- It does not know your credit file. Approval, the credit limit you are given and the effect of a new application on your credit score are outside this calculation.
- Fees, rates and terms differ by card and country. This is a comparison of the numbers you enter, not advice on which card to choose.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- 12 CFR 1026.22 (Regulation Z) - Determination of annual percentage rate - checked 19 Sep 2026
- 12 CFR 1026.55 (Regulation Z) - limitations on increasing APRs, including promotional rates
- 12 CFR 1026.53 (Regulation Z) - allocation of payments to balances with different rates
Frequently asked questions
Is a balance transfer worth it with a 3% fee?
Usually yes, if you would otherwise pay a high APR for more than a couple of months and you can clear most of the balance within the offer. On $5,000 at 24% paid at $300 a month, a 15-month 0% offer with a 3% fee saves about $970. Enter your own figures to check.
How is a balance transfer fee calculated?
As a percentage of the amount transferred, often with a minimum. A 3% fee on $5,000 is $150, and it is added to the new card's balance, so you start the offer owing $5,150. Some cards charge 5%, and a few have introductory 0% fees.
What happens when a 0% balance transfer period ends?
Any balance still owed starts accruing interest at the card's standard rate from the next billing cycle. The calculator shows how much will be left at that point and the monthly payment that would clear the transferred balance, fee included, before the offer ends.
How much should I pay each month on a 0% balance transfer?
Divide the new balance, including the fee, by the number of 0% months. $5,150 over 15 months is $343.34 a month. Paying at least that clears the debt before any interest is charged.
Can I use a balance transfer card for new purchases?
You can, but new purchases are often charged the full purchase APR and minimum payments may go to the 0% balance first, so purchase interest can build up. Many people keep the transfer card for the transferred debt only.
Does the calculator work for UK and Indian credit cards?
Yes. The arithmetic is the same anywhere; choose the currency and enter the APR, fee and promotional period from the offer. Indian card issuers often call a balance transfer a "balance transfer on EMI", with a processing fee and GST on top, so add those to the fee.
Last reviewed by the A2Z.Tools team against the sources listed above.
