Credit card offer math

Balance transfer calculator: compare fee, promo window, and payoff risk.

A balance transfer can reduce interest during a promotional period, but the fee, payment size, post-promo APR, and credit limit can change the math. Use this local estimate before treating an offer as cheaper.

By CashTalks ·

Balance-transfer calculator

Compare the current card path with a transfer offer

Enter your balance, current APR, payment, transfer fee, promotional APR, promotional months, and post-promo APR. The estimate compares interest, fee, break-even timing, and whether the promo window looks long enough under the entered payment.

Current path

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Transfer offer

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Educational assumptions

  • Same fixed monthly payment on both paths.
  • Transfer fee is added to the transferred balance at the start.
  • Monthly compounding from the APRs entered.
  • No new purchases, missed-payment penalty APR, approval guarantee, credit-limit guarantee, or credit-score estimate.

Break-even month

This is the first month when estimated transfer fee plus transfer interest is lower than current-path interest. If it is not reached, the fee may outweigh the interest reduction under the inputs entered.

Promo payoff feasibility

This checks whether the entered payment is enough to pay the transferred balance and fee during the promotional window. It does not guarantee approval, limit size, or statement timing.

Old-card spending risk

A transfer can backfire if the old card gets used again, the new payment is unaffordable, or the balance remains high when the post-promo APR starts.

Assumptions

  • The same fixed monthly payment is used for the current path and the transfer path.
  • The balance transfer fee is added to the transferred balance at the beginning.
  • Interest is estimated with monthly compounding from the APRs entered.
  • The estimate does not include new purchases, late fees, missed-payment penalty APRs, annual fees, payment allocation rules, credit-limit constraints, or application outcomes.
  • A lower estimated cost is not a promise of savings because approval, credit limit, terms, and behavior after the transfer can change the result.

Not sure how to read the result?

Penny can help interpret the tradeoffs and questions to ask before applying.

Continue with Penny

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