What Happens If You Go Into an Unarranged Overdraft? UK

What Happens If You Go Into an Unarranged Overdraft?

Last updated: July 2026  |  Reading time: 6 minutes

Your card gets declined at the till. Or worse, it doesn’t — and three days later you check your balance and it’s £43 more negative than you thought possible, with a charge you don’t recognise sitting next to it.

Going over your agreed limit, or spending money you don’t have with no overdraft arranged at all, used to be one of the most punishing things you could do to your bank balance. Before 2020, some banks charged the equivalent of over 3,000% APR for it — genuinely worse than a payday loan.

That changed. Here’s what actually happens now, and what it costs you today.

First — what actually counts as “unarranged”

An arranged overdraft is a limit your bank has agreed to in advance — say £500. An unarranged overdraft happens one of two ways: you go past that agreed £500 limit, or you don’t have an overdraft facility set up at all and your account still goes negative because a payment went through anyway.

Both used to be treated very differently by banks — and very badly. Since April 2020, they’re treated the same way, and that’s the single biggest thing to understand about how this works now.

What changed in 2020, and why it actually matters

The Financial Conduct Authority stepped in because unarranged overdraft charges had gotten genuinely absurd. Some banks charged around £5 a day in fixed fees just for being in an unarranged overdraft — regardless of whether you owed £10 or £500. Annualised, that worked out to APRs the FCA itself described as up to 20 times higher than payday loan rates.

From 6 April 2020, banks were banned from charging those fixed daily or monthly fees entirely. The only thing they’re now allowed to charge is a single annual interest rate — and crucially, that rate has to be the same whether you’re in an arranged or unarranged overdraft. Banks can no longer punish you extra just for going over the agreed line.

The FCA’s own evaluation found the reform saved customers about £1 billion combined, with the average overdraft user saving £17.40 in 2021 alone. Seven out of ten overdraft users ended up better off or unchanged.

What it actually costs you today

Major UK banks currently charge somewhere between 19.9% and 39.9% EAR (effective annual rate) on overdraft borrowing — arranged or unarranged, same rate either way. A handful of banks, including Monzo and Starling, use tiered rates based on your individual credit profile instead of one flat number for everyone.

Here’s what that actually looks like in pounds: at 39.9% EAR, being £500 into your overdraft for a full month costs you roughly £16. Compare that to the old system, where the same £500 for a month at a typical £5-a-day fixed fee would have cost around £150 — nearly ten times more for identical borrowing.

That’s the real story here: unarranged overdrafts are no longer the near-worst borrowing option on the market. They’re now genuinely comparable to a standard credit card, sometimes cheaper.

What can still go wrong, even under the new rules

The interest cost is fairer now, but a few things still bite:

Refused payment fees still exist. If a direct debit or standing order can’t go through because there’s no money — or no unarranged overdraft space — left to cover it, banks can still charge a fee for refusing that payment. The FCA’s guidance says this fee should reasonably reflect the actual cost of refusing the payment, not be used as a backdoor way to punish unarranged borrowing again.

Repeated use gets flagged. Since December 2019, banks are required to actively monitor customers showing signs of financial strain from repeated overdraft use, and to put a support strategy in place. If you’re dipping into an unarranged overdraft most months, expect your bank to reach out — that’s not a threat, it’s a regulatory requirement designed to catch problems early.

It still shows up on your credit file. Regularly using an unarranged overdraft, or exceeding your limit repeatedly, is visible to other lenders and can affect future credit applications — the interest rate reform didn’t change how this gets reported.

The insight most guides on this miss entirely

Because arranged and unarranged overdrafts are now priced identically, the smartest move if you regularly go over is simply to ask your bank to raise your arranged limit. It costs you nothing extra in interest rate — you’re already paying the same rate either way — but it removes the refused payment fees and the repeat-use flags entirely. Most people don’t realise this is even possible, because the old system trained everyone to think unarranged overdrafts were something separate and worse. They’re not, anymore. They’re just the same borrowing without the paperwork.

If you want to get out of it for good

Building even a small buffer changes the whole equation. A £100–£200 cushion in a separate account means one unexpected bill doesn’t tip you into unarranged territory at all.

If switching banks for a cheaper overdraft rate makes sense for you, the Current Account Switch Service completes full switches — including transferring every direct debit and standing order automatically — within 7 working days. Your existing overdraft balance has to be cleared or separately arranged with your old bank first; it doesn’t just vanish when you switch.

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