Balance Transfer Calculator
See how a balance transfer fee, promo APR period, and post-promo APR affect your total interest and payoff time.
How to Use
- Enter the balance you're considering transferring, and the transfer fee your new card charges (commonly 3–5% — leave at 0 if there's none).
- Enter the promotional APR (often 0%) and how many months it lasts, plus the regular APR that applies after the promo period ends.
- Enter the fixed amount you plan to pay every month — this stays the same before and after the promo ends.
- The result shows the transfer fee, your effective starting balance, how long payoff takes, and interest paid separately during and after the promo period, so you can see exactly what the transfer costs (or saves) you.
Formula
- Transfer fee
- fee = balance_to_transfer × fee_percent ÷ 100
- Starting balance
- starting_balance = balance_to_transfer + fee
- Promo phase
- simulated month by month at the promo APR, for exactly the promo duration (or until paid off, if sooner)
- Post-promo phase
- any balance remaining after the promo continues, simulated month by month at the post-promo APR, until paid off
Worked Example
A $5,000 balance, 3% transfer fee, 0% promo APR for 15 months, 22% APR after that, paying $300/month.
- Transfer fee: $5,000 × 3% = $150.00
- Starting balance: $5,000 + $150 = $5,150.00
- Promo phase (0% APR, 15 months, $300/month): pays down $4,500, leaving $650.00 with $0 promo interest
- Post-promo phase (22% APR, $300/month): the remaining $650 is paid off in 3 more months, with $19.81 interest
- Total: 18 months, $19.81 total interest, $5,169.81 total paid
Result: Balance transfer fee: $150.00 / Starting balance after fee: $5,150.00 / Time to pay off: 18 months (1.5 years) / Interest paid during promo period: $0.00 / Interest paid after promo period: $19.81 / Total interest paid: $19.81 / Total amount paid: $5,169.81
About This Tool
What this tool does
This calculator models a balance transfer end to end: the fee added to your balance, how much of it a fixed payment pays off during the promotional rate period, and what happens to any amount left over once the regular APR kicks back in.
When to use it
Use it to check whether a balance transfer offer is actually worth the fee — compare its total interest and payoff time against paying the original balance down directly with the Credit Card Payoff Calculator.
What the result means
Interest paid during the promo period is usually $0 (a 0% promo APR is the most common offer), so most of the "cost" here is often the transfer fee itself, not interest. Interest paid after the promo period only appears if your payment hasn't fully paid off the balance by the time the promo ends — that's the number a low, slow payment plan can quietly rack up.
Assumptions & limitations
The transfer fee is modeled as a flat percentage of the balance transferred with no cap — some real cards cap the fee at a fixed dollar amount regardless of balance size, so check your actual offer's terms. The fee is assumed to be added to your balance immediately and to accrue interest like the rest of it. Your monthly payment is assumed to stay exactly the same before and after the promo ends, and the promo period is assumed to start immediately upon transfer. This is an estimate only, not a financing offer — actual promotional terms, fees, and APRs vary by card issuer and by your creditworthiness.