Balance Transfer Calculator
Balance & offer
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Fill in the fields and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- United States — Truth in Lending disclosure and the CARD Act set the floor; the terms that decide your balance are in your cardholder or loan agreement
- Rules and time period
- APRs, fees, promotional periods and minimum-payment formulas are the ones you enter; an issuer can change several of them with notice.
- Scope and limitations
- Educational estimate only. Your issuer sets the minimum-payment formula, how a payment is allocated across balances, when interest is charged and any fees or promotional terms — check your agreement for the figures that bind, and expect a payoff date to move if a payment is late.
- Source links checked
- Sep 19, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
Primary sources
How to use
- 01
Enter the balance you would move and the APR you are paying on it now.
- 02
Enter the offer's promotional APR — usually 0% — and how long that window lasts. Fifteen, 18 and 21 months are the common U.S. terms, and the length is what decides the whole question; your offer letter has the exact one.
- 03
Enter the transfer fee, typically 3% to 5% of the amount moved, and what you can pay each month. A transfer only saves money if the balance actually falls during the promo.
- 04
Open Advanced options if the rate after the promo is not the rate you pay now. It only bites on a balance that has not cleared by the time the window closes.
- 05
Read the net saving and the side-by-side table, then check whether any of your payoff falls after the promo ends — those months are charged at the revert rate.
Formula
A transfer moves the balance to a new card at a promotional rate for a fixed number of months, in exchange for a fee charged up front and added to the transferred balance. The tool simulates both paths month by month at your payment. Staying: the balance accrues at your current APR until it clears. Transferring: the balance plus the fee accrues at the promotional rate for the promo months, then at the revert rate for however long is left. Net saving = interest if you stay - (fee + interest after transferring). Because the promo has an end date, any months of payoff that fall past it are charged at the revert rate — the tool names that tail in months and dollars, since it is what decides whether an offer is worth taking.
Example
Inputs: a $6,000 balance at 22% APR, an offer of 0% for 15 months with a 3% transfer fee reverting to 22%, and $300 a month. Step 1 — Size the fee. $6,000 x 3% = $180. It is added to the balance, so you transfer $6,180. Step 2 — Price staying put. At 22% paying $300 a month the card clears in 2 years 2 months and costs $1,543 in interest. Step 3 — Price transferring. During the 15-month promo, 0% means every dollar of the $300 goes to principal: $4,500 comes off, leaving $1,680. From month 16 the revert rate applies, and the remainder takes 6 more months at 22%, costing $109. Total time: 1 year 9 months. Step 4 — Compare. Staying costs $1,543 of interest. Transferring costs $180 of fee plus $109 of interest, $289 in all. Result: a net saving of $1,254, and the card clears five months sooner. Note the tail — 6 of those 21 months fall after the promo ends. Paying $412 a month instead would clear the balance and the fee inside the 15-month window, which is the only way a 0% offer costs nothing beyond its fee.
Definitions
- Balance transfer
- Moving debt from one card to another, normally to take a lower promotional rate for a fixed period.
- Promotional APR
- The temporary rate on the transferred balance, often 0%. It applies for a set number of months and then reverts.
- Promo window
- How long the promotional rate lasts — typically 12 to 21 months. The single most important number in the offer after the fee.
- Revert rate
- The APR that applies once the promo ends, charged on whatever balance remains. Often as high as the card the balance came from.
- Transfer fee
- A one-off charge for moving the balance, usually 3% to 5% of the amount. It is normally added to the new balance, so it accrues interest too.
- Deferred interest
- A promotion that waives interest only conditionally: if any balance remains at the deadline, every waived dollar is charged retroactively.
- Break-even
- The point at which the interest a transfer saves exceeds the fee it costs. Below it, staying put is cheaper.
- Hard inquiry
- The credit check an application triggers. It costs a few points and fades within a year, though it stays on the report for two.
- Credit limit
- The maximum the new issuer will let you carry — and therefore the ceiling on how much you can transfer.
- Utilization
- Balances divided by limits. A transfer usually improves it by adding a limit without adding debt.
- Payment allocation
- How an issuer applies your payment. Anything above the minimum must go to the highest-APR balance first, which matters when a promo balance and a purchase balance share a card.
- Offer expiry
- The deadline for completing the transfer after opening the account, commonly 60 to 120 days. Missing it can forfeit the promotional rate.
Good to know
What a balance transfer actually buys you
A balance transfer moves debt you already owe from a card charging a high rate onto a different card offering a low promotional rate, usually zero percent, for a fixed number of months. Nothing about the amount owed changes at the moment of transfer except that interest stops, or nearly stops, accumulating. The principal travels with you. What you are buying is time: a window during which every dollar you pay lands almost entirely on principal instead of being split between principal and interest. Take a $6,000 balance at 22 percent, which would otherwise bleed about $110 in interest in the very first month alone; it stops doing so the instant it sits on a zero percent card. That paused interest is the whole point. But the offer is not free. The new card charges a transfer fee, here 3 percent, added to the moved balance on day one. So the honest question is never simply whether zero percent beats 22 percent, which it obviously does, but whether the interest you avoid is larger than the upfront fee you pay to avoid it. This tool answers exactly that by simulating both paths at the identical monthly payment and reporting the net result. Treat the transfer as a tool for breaking the interest cycle on a balance you are already committed to clearing, not as new spending power. The card has not forgiven anything; it has rented you a quiet period, and the rent is the fee. Whether that rent is worth paying is a number, not a slogan.
The fee-versus-interest break-even, in plain terms
The single calculation that decides whether a transfer is worth doing is a subtraction. On one side sits the interest you would pay by staying put; on the other sits the fee plus any interest you would still pay after transferring. The tool computes the first by simulating payoff of your current balance at your current rate, and the second by simulating payoff of your balance plus the fee at the promotional rate. The net saving is stay-interest minus the sum of fee and transfer-interest. When that result is positive, the transfer keeps money in your pocket; when negative, the fee has eaten more than the interest you saved. Take a $6,000 balance at 22 percent paid at $300 a month, against an offer of 0 percent for 15 months with a 3 percent fee. The stay path costs about $1,543 in interest, while the transfer path costs the $180 fee plus $109 of interest on the tail that falls after the promo ends, leaving a net saving of about $1,254. The break-even point is the fee level at which those two sides are equal. Because the promotional rate here is zero, nearly all of the transfer's cost is the fee, so the transfer keeps winning until the fee alone approaches the interest avoided. Push the fee to 10 percent, the highest this tool accepts, and the saving only narrows to about $774 — still comfortably positive, which is why a genuine zero percent transfer on a high-rate balance is so often worthwhile. The lesson is structural: a transfer is attractive when the rate gap is wide and the balance lingers long enough to accrue real interest, and unattractive when the gap is narrow, the fee is steep, or the balance is so small it would clear cheaply anyway.
Why the same monthly payment is the only fair comparison
It is tempting to compare a transfer by imagining you pay the minimum on the old card but throw everything at the new one. That is not a comparison; it is two different plans, and it flatters the transfer for reasons that have nothing to do with the rate. This tool removes that distortion by holding the monthly payment identical on both paths. A payment of $300 a month is applied to the stay scenario and the transfer scenario alike, so the only things that differ are the interest rate and the fee. That discipline matters because payment size, not rate, is usually the biggest driver of how much interest a debt accrues. A bigger payment clears principal faster, which starves interest on either card. If you let the payment float, you could make almost any transfer look good or bad at will. By fixing it, the tool isolates the real question: given that you will commit the same money each month, does swapping the rate and paying the fee leave you better off. The honest way to read the result is therefore to first decide what you can sustainably pay every month, enter that figure, and keep it constant. If you can genuinely afford more after transferring, model that higher figure on both sides to see its effect, but never compare a high transfer payment against a low stay payment. The apples-to-apples payment is what makes the net saving trustworthy, and it is the assumption most casual transfer comparisons quietly violate.
Can you clear the balance inside the promo window?
A promotional rate is not permanent. It lasts a set number of months, and the entire value of a transfer depends on whether you can extinguish the balance before that window closes. The tool's payoff simulation tells you how many months your chosen payment needs. On a $6,000 balance with a 3 percent fee the moved balance is $6,180, and at $412 a month a zero percent balance falls by exactly $412 each month, clearing in fifteen months. If your offer's window is fifteen months or longer, the whole balance dies inside the promotional period and you pay only the $180 fee. If the window is shorter, say twelve months, the same balance would need about $515 a month to finish in time, and any amount left when the clock runs out reverts to a standard rate. The arithmetic for an interest-free transfer is refreshingly simple: required monthly payment equals the balance plus fee divided by the number of promotional months. Compare that figure honestly against what you can actually pay. The most common transfer mistake is treating the headline zero percent as the prize while ignoring the deadline attached to it. A transfer you cannot finish in time is not a zero percent loan; it is a fee-plus-deferred-interest arrangement wearing a zero percent label. Before committing, divide your balance by the months on offer, confirm you can sustain that payment through job changes and emergencies, and leave yourself a cushion. The window is the constraint that turns a good offer into a real saving rather than a deferred problem.
What happens when the promo rate ends
Every promotional rate has a morning after. Whatever balance remains when the introductory period expires stops being interest-free and begins accruing at the card's standard, or go-to, rate, which is frequently as high as or higher than the rate you transferred away from. This is where transfers quietly fail. Suppose you move a $6,000 balance plus its fee but only pay enough to clear part of it before the window shuts; the leftover lands on a rate that can rival the original 22 percent, and the interest clock you paused restarts on the remaining sum. The fee you paid to escape interest now buys you nothing on that residual balance. At $300 a month on a 15-month offer, six of the twenty-one payoff months fall after the promo ends, and the $109 the tool reports as interest after transfer is exactly the price of that tail. The disciplined approach is to plan for the balance to hit zero with months to spare, not to bet on finishing exactly at the deadline. Read the card's terms for the post-promotional rate before transferring, because that number is what governs any slippage. Resist the instinct to relax once the high-rate pressure lifts; the absence of monthly interest can make a balance feel smaller and less urgent than it is, and that comfort is precisely what leaves a stub to revert. A transfer rewards the borrower who treats the promotional window as a hard countdown to zero and penalizes the one who treats it as a holiday. Plan the payoff, then beat it.
The deferred-interest trap to watch for
Not every zero percent offer works the same way, and the most dangerous variety is deferred interest rather than waived interest. Under a true waived-interest promotion, the interest that would have accrued during the window is simply forgiven, and if a balance remains afterward, only that remaining balance accrues interest going forward. Under a deferred-interest promotion, interest is silently calculated and stored in the background from day one, and it is only canceled if you clear the entire balance before the window ends. Miss the deadline by a single dollar or a single day, and the whole stack of back-interest, computed on the original balance for the full promotional period, is added at once. The difference is enormous. On a $6,180 transferred balance, fifteen months of background interest at 22 percent would land retroactively and could exceed the entire interest bill you were trying to escape, turning a seemingly cheap zero percent deal into one of the most expensive ways to carry debt. This tool models a straightforward promotional rate and does not assume a deferred-interest structure, so if your offer carries one, the real downside of missing the window is far worse than the simulation's clean numbers suggest. Protect yourself by reading whether the offer says interest is waived or deferred, treating any deferred-interest deal as all-or-nothing, and aiming to clear the balance well before the deadline rather than at it. The safest deferred-interest plan finishes a month or two early on purpose. When in doubt, assume the harsher structure and pay as though every remaining dollar at the deadline could trigger the full retroactive charge.
Reading the net saving, fee, and interest figures
The tool returns four numbers worth understanding individually rather than glancing at the headline alone. The net saving is the bottom line: stay-interest minus the sum of fee and transfer-interest, positive when transferring helps and negative when it hurts. On a $6,000 balance at 22 percent paid at $300 a month against a 0 percent, 15-month, 3 percent-fee offer, this is about $1,254 in your favor. The transfer fee, here $180, is the upfront, certain cost you accept in exchange for the rate cut; it is the same whether or not the plan goes perfectly. Interest if you stay, about $1,543, is the interest your current card would charge over the full payoff at your current rate and payment. Interest after transfer, $109 in that example, is what the promotional card charges on the moved balance plus fee. Reading them together tells a fuller story than the headline. A large positive saving driven mostly by a high stay-interest figure means your current rate is genuinely punishing and almost any reasonable transfer helps. A thin saving means the fee is consuming most of the benefit, and small changes to fee or payment could flip the decision, so test them. If transfer-interest is non-zero, either your promotional rate is above zero or the balance does not clear before the window shuts, and it is worth raising the payment until that figure falls to zero. The figures are not just a verdict; they are a diagnosis. Adjust the inputs and watch which number moves to learn whether your decision rests on a wide rate gap, a forgiving fee, or a payment large enough to finish quickly.
When a transfer is the wrong move
A transfer is a tool, and like any tool it is wrong for some jobs. It disappoints when the fee is large relative to a small or short-lived balance: a $1,000 balance cleared in four months at $300 a month avoids only $42 of interest against a $30 fee, a net saving of $12 that is barely worth the paperwork, and a steeper fee on the same balance would turn the saving negative. It disappoints when the rate gap is narrow, because a promotional rate only a few points below your current one leaves little interest to save against the fee. It disappoints most of all when you cannot realistically clear the balance inside the window, since the leftover reverts to a high rate and, under a deferred-interest structure, can trigger retroactive charges that dwarf the fee. There is also a behavioral failure mode the arithmetic cannot capture: a transfer empties your old card's balance, and if the temptation to spend on that newly available limit is real, the transfer can leave you with two balances instead of one. The tool will tell you when the fee outweighs the interest saved, but it cannot tell you whether you will keep paying the same amount or keep the old card idle. Before transferring, confirm three things the calculator cannot: that you can sustain the payment for the whole window, that you will not re-borrow on the cleared card, and that your offer is genuine waived interest rather than the deferred kind. If any of those is shaky, the clean positive number on screen may overstate the real outcome. A negative net saving is a clear no; a thin positive one deserves a second look at your own discipline.
How fee size and rate gap drive the decision
Two levers move the transfer verdict more than any others: the size of the fee and the width of the rate gap. The fee is a fixed percentage of the balance, charged once and added to what you owe, so a 3 percent fee on $6,000 is $180 regardless of how the rest of the plan unfolds. It is the certain cost. The rate gap, the distance between your current rate and the promotional rate, determines how much interest you stand to avoid, but only in combination with how long the balance lingers. A wide gap on a balance that clears slowly avoids a great deal of interest; the same gap on a balance that clears in two months avoids almost nothing. This is why the fee has so much room to move on a $6,000 balance at 22 percent: the 22-point gap against a zero percent promo, applied to a balance that takes over two years to clear at $300 a month, accumulates roughly $1,543 in avoidable interest, so even the 10 percent fee at the top of this tool's range still leaves about $774 of saving. Flip the inputs and the logic reverses. Narrow the gap by entering an 18 percent promotional rate instead of zero and the saving collapses from about $1,254 to about $39. Raise the fee and the certain cost climbs toward the avoided interest. Shrink the balance or raise the payment so the debt clears quickly, and there is simply less interest to avoid. The disciplined way to use the tool is to vary these two inputs around your real offer and watch the net saving cross zero, which shows you exactly how much margin your decision actually has.
Frequently asked questions
Is a balance transfer worth the fee?
Only if the interest it saves exceeds the fee. On $6,000 at 22% paying $300 a month, a 3% fee costs $180 and saves about $1,254 — clearly worth it. At a small balance, a low rate, or a fast payoff, the fee can be larger than the interest avoided.
What happens when the 0% period ends?
Whatever is left starts accruing at the revert rate, which is often as high as the card you transferred from. This calculator charges those months explicitly rather than pretending the promo lasts forever.
What is deferred interest, and is it the same thing?
No, and the difference is expensive. A true 0% APR offer charges nothing during the promo and normal interest afterwards. A deferred-interest offer charges all the interest it waived, retroactively, if any balance remains at the deadline.
Does a balance transfer hurt my credit score?
Briefly. The application adds a hard inquiry and lowers your average account age. But the new card's limit raises your total available credit, so overall utilization usually falls — which typically helps within a few months.
Can I transfer more than the new card's limit?
No. Issuers approve a transfer up to your new credit limit, and often only up to a portion of it. If your balance is larger, you can move part of it and keep paying the rest on the original card.
Can I transfer a balance between cards from the same bank?
Generally not. Almost all issuers prohibit transfers between their own accounts, so a transfer means moving to a different bank.