How it works
A balance transfer calculator compares two ways to retire credit card debt: staying put at your current APR, or moving the balance to a card offering a promotional rate, paying the transfer fee, and attacking it hard. Standing still is simple arithmetic - interest compounds monthly until the balance dies. The transfer path adds moving parts: a fee, typically 3-5% of the amount moved, usually posts to the new card immediately; the promotional rate applies only for the intro window; and whatever survives past the cutoff reverts to the regular APR, which on these cards is anything but gentle. The calculator simulates both timelines month by month with your actual payment, nets the fee against the interest avoided, and reports what the maneuver truly saves. The economics hinge on one behavior: the payment must be large enough to finish inside the promo. Move $6,500 at $300 a month into a 15-month 0% window and the fee-plus-interest cost runs a few hundred dollars against nearly $2,000 of interest paid standing still. Keep making minimum-sized payments afterward, though, and the promo was theater - the debt simply changed rooms.
Formula
Net savings = interest avoided at current APR - transfer fee - post-promo interest
Tips
- Run the numbers only if you will genuinely finish inside the intro window.
- Stop new spending on both cards during the promo - purchases earn no grace.
- Automate the minimum immediately; one late payment can cancel the intro rate.
- Ask about no-fee transfer offers - several issuers run them periodically.
- Keep the old card open but unused; closing it dings utilization and history.
Frequently asked questions
- How does a balance transfer work?
- The new card pays off your old balance directly, the amount (plus a fee of usually 3-5%) posts to the new account, and a promotional APR applies for a fixed window - often 12-21 months. After the window, the regular purchase APR applies to whatever remains.
- Is a balance transfer worth the 3% fee?
- Almost always, when compared to carrying the same balance at 20%+ APR - a $6,500 transfer costs $195 against roughly $2,000 of interest avoided over a year and a half at the same payment. The fee only loses when the payoff drags past the promo into the regular rate.
- What happens when the 0% APR period ends?
- The remaining balance instantly accrues interest at the card's regular rate - often 25-30%. There is no grace ramp, which is why the calculator shows the payoff date and why the payment must be sized to finish before, not after, the cliff.
- Will a balance transfer hurt my credit score?
- Briefly, possibly: the application adds an inquiry and the new account shortens average age. But lowering revolving balances cuts utilization, which usually outweighs those effects within a few months - especially if the old card stays open unused.
- Can I transfer a balance to a card I already have?
- Rarely useful - issuers exclude existing accounts from promo offers, and transfers between cards from the same bank are usually blocked. The play is a genuinely new card whose intro terms fit the payoff schedule you can commit to.