0% Balance Transfer Calculator UK [2026]

Q: What monthly payment do I need to clear the balance before the 0% ends?

Divide the transferred balance plus the transfer fee by the number of 0% months you have. On a £2,500 balance with a 2.9% fee and 18 months at 0%, that is roughly £143 a month. Paying that fixed amount clears the balance the same month the deal expires, so nothing reverts to interest. The calculator shows this figure as your required monthly payment.

Q: What happens to any balance left when the 0% period ends?

Whatever is left starts charging interest at the card's revert APR — typically 24.9% to 29.9% in the UK. The calculator carries your remaining balance into the revert rate at your chosen monthly payment and shows how many extra months it takes and how much interest it adds, so a shortfall is never a surprise.

Q: Should I enter 0% as the promotional rate?

For a genuine 0% deal, yes — leave the promotional rate at 0%. Some cards instead offer a low promotional rate (for example 2.9% for a longer period) rather than a true 0%. If that is your deal, enter the actual promotional rate and the calculator will apply it during the promo window before switching to the revert APR.

Q: What if I can't clear the balance before the promotional period ends?

A transfer can still save money even if you do not clear it in full, because it pauses interest for the whole promotional window. But plan ahead: increase your monthly payment if you can, or line up another 0% transfer for the remaining balance before the deal expires and while your credit is still strong. If the minimum payments are already unaffordable, seek free debt advice before taking on new credit.

A 0% balance transfer calculator works out the monthly payment that clears your card balance before the interest-free period ends. It adds the transfer fee (typically around 2.9%) to your balance, divides by the months of 0% you have left, and — if you can't clear it in time — shows the balance remaining and the interest it will cost at the revert APR. Clearing before the deal expires is what makes a transfer save you money.

Your balance transfer

Balance to transfer

The amount you'll move to the new card

Balance transfer fee

One-off fee, added to your balance

0% period remaining

Months left on the promotional deal

Promotional rate

Usually 0% — change it for a low-rate promo

Revert APR after promo

The standard rate once the 0% ends

Monthly payment you can afford

What you can realistically pay each month

Original card APR (for comparison)

The rate on the card you'd transfer away from

Enter your balance transfer details above — the results update instantly. This calculator shows the monthly payment that clears your balance before the 0% period ends, whether the payment you can afford gets there in time, and what any remaining balance costs at the revert APR.

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On track

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Payment needed to clear in time

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Transfer fee

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Total interest on the transfer

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Total cost of the transfer (fee + interest)

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Transfer vs staying on your current card

Balance over time

Balance during the 0% period Danger zone — balance charged at the revert APR Staying on your current card

Plan the rest of your debts with the Snowball calculator

Key takeaways

The transfer fee is added to your balance, so a £2,500 move with a 2.9% fee starts as £2,572.50 on the new card.
Divide that total by your months of 0% to get the payment that clears the balance exactly as the deal ends.
Anything left when the 0% expires jumps to the revert APR — usually 24.9%–29.9%. The calculator shows exactly what that costs.
A transfer still helps even if you can't clear it in full, because it pauses interest for the whole promotional window.

How this 0% balance transfer calculator works

It answers two questions: what payment clears your balance before the 0% ends, and what a shortfall costs if you can't quite manage that.

Every figure updates the moment you change an input — there's no button to press. Here's what the tool does behind the scenes:

Adds the fee to your balance. UK cards add the transfer fee to the amount you move, so the calculator starts from your balance plus the fee.
Finds the required payment. It works out the fixed monthly payment that clears that total exactly as your 0% months run out — the payment that gets you to zero with nothing left to revert.
Tests what you can afford. It then simulates the monthly payment you entered. If it clears the balance in time, you're done for the price of the fee alone. If it falls short, the tool carries the leftover balance past the promo-end date and charges it at the revert APR, month by month, until it's gone.
Compares against doing nothing. Finally it runs the same balance and payment on your existing card's APR, so you can see the transfer's saving — or, occasionally, that a small balance on a short deal isn't worth the fee.

The revert-rate trap the calculator is built around

A 0% deal is an interest-free window, not interest-free debt. The day it closes, whatever is left reverts to the standard APR.

This is the mistake most people make and most calculators ignore. If you only make minimum payments, most of the balance is still there when the deal ends — and it lands straight on a rate that's often as high as the card you transferred away from. That's why this tool leads with the required payment and shades a red "danger zone" on the chart for any months your balance spends at the revert rate. The 0% balance transfer strategy guide explains the trap and how to avoid it in full, including setting a calendar reminder before the expiry date and lining up a second transfer if you'll need one.

How a transfer fits your wider debt plan

A balance transfer changes one debt's interest rate; the order you clear your debts is a separate decision.

The smart play is to park your most expensive balance at 0%, keep it running on the clearing payment above, then attack everything else. Clear your smallest balances first for momentum with the debt snowball calculator, or rank every debt by interest rate with the debt avalanche calculator — at 0%, the transferred card sits last in avalanche logic because it's the cheapest debt you have. For the strategy behind all three, see how to pay off credit card debt in the UK.

What the calculator assumes

Results are estimates. The tool applies interest monthly (the annual rate divided by twelve), assumes your payment stays the same each month, adds no new spending to the card, and holds each rate constant for the whole projection. In reality, missing a payment usually voids the 0% rate immediately, and new purchases are rarely covered by the promotional deal — so treat a transfer card as a debt-clearing tool, not a spending card. Revert rates and typical fees reflect the UK market in 2026; average card rates are published by the Bank of England. Always check the current terms before you apply.

Frequently asked questions

How does a 0% balance transfer calculator work?

It adds the transfer fee to your balance, then works out the fixed monthly payment that would clear that total exactly as the 0% period ends. It also simulates the payment you can afford: if that's enough, you're clear in time; if it falls short, the tool carries the leftover balance into the revert APR and calculates the extra interest, so you see the true cost before you apply.

What monthly payment do I need to clear the balance in time?

Divide the transferred balance plus the fee by the number of 0% months you have. On a £2,500 balance with a 2.9% fee and 18 months at 0%, that's roughly £143 a month. Paying that fixed amount clears the balance the same month the deal expires, so nothing reverts to interest. The calculator shows this as your required monthly payment.

What happens to any balance left when the 0% ends?

Whatever's left starts charging interest at the card's revert APR — typically 24.9% to 29.9% in the UK. The calculator carries your remaining balance into the revert rate at your chosen monthly payment and shows how many extra months it takes and how much interest it adds, so a shortfall is never a surprise.

Is the balance transfer fee added to my balance?

Yes. On UK balance transfer cards the fee — commonly around 2.9% of the amount moved — is added to the transferred balance rather than charged separately, so a £2,500 transfer with a 2.9% fee starts life as £2,572.50. This calculator adds the fee to your balance before working out payments, exactly as the card does.

Should I enter 0% as the promotional rate?

For a genuine 0% deal, yes — leave it at 0%. Some cards instead offer a low promotional rate (for example 2.9% for a longer period) rather than a true 0%. If that's your deal, enter the actual promotional rate and the calculator applies it during the promo window before switching to the revert APR.

What if I can't clear the balance before the promo ends?

A transfer can still save money even if you don't clear it in full, because it pauses interest for the whole promotional window. But plan ahead: increase your payment if you can, or line up another 0% transfer for the remaining balance before the deal expires and while your credit is strong. If the minimum payments are already unaffordable, get free debt advice before taking on new credit.

DebtSnowball.co.uk is not regulated by the Financial Conduct Authority (FCA) and does not provide regulated debt or credit advice. This calculator is general information only, not tailored to your circumstances, and is not a recommendation of any particular card or product. Balance transfer rates, fees and eligibility change frequently — always check the current terms before applying. If you're struggling with debt, free, impartial and regulated advice is available from StepChange, Citizens Advice, National Debtline and MoneyHelper.

Disclaimer: This calculator is for informational purposes only and does not constitute financial advice. Results are estimates based on the figures you enter and assume a constant promotional and revert rate, a fixed monthly payment and no new spending on the card. You remain responsible for meeting every payment. If you are struggling with debt, contact a free UK debt advice service such as StepChange (stepchange.org). For personal advice, consult an FCA-regulated adviser.

0% Balance Transfer Calculator