Late Tax Return Penalties in the UK and How to Avoid Them

When Does a Late Filing Penalty Apply?

The deadline for submitting your Self Assessment tax return online is 31 January, following the end of the tax year on 5 April. If you file a paper return, the deadline is earlier, on 31 October.

A penalty applies as soon as you miss your filing deadline, regardless of whether you owe any tax. Even if HMRC ends up owing you a refund, you can still be charged for filing late, so it's worth submitting on time every year.

The Initial £100 Penalty

If your tax return is even one day late, HMRC will usually issue a fixed £100 penalty. This applies automatically and isn't linked to how much tax you owe, so it can catch people out who assume no penalty applies because their tax bill is low or nil.

Daily Penalties After Three Months

If your return is still outstanding three months after the deadline, HMRC can start charging additional daily penalties of £10 per day, up to a maximum of 90 days. That's up to £900 on top of the initial £100 fixed penalty, so delays can add up quickly.

Six-Month and Twelve-Month Penalties

The penalties don't stop there. If your return is still late after six months, HMRC can charge a further penalty of whichever is higher: £300 or 5% of the tax due. The same again applies at the twelve-month mark. In cases where HMRC believes information has been deliberately withheld, these penalties can be higher still.

Late Payment Penalties Are Separate

For most Self Assessment taxpayers, the online tax return and balancing payment are due by 31 January following the end of the tax year. However, filing and paying are treated separately by HMRC, so meeting one deadline doesn't automatically mean you've met the other.

If you file on time but don't pay what you owe, you can still face late payment penalties, along with daily interest on the outstanding amount. HMRC's interest rate changes from time to time, so it's worth checking the current rate on HMRC's website rather than assuming it stays fixed.

What About Making Tax Digital (MTD) Penalties?

If you're required to use Making Tax Digital for Income Tax, the penalty position is currently transitional. For the 2026/27 tax year, HMRC has confirmed it will not issue penalty points for late quarterly updates, although updates still need to be submitted before your tax return can be filed. Penalties can still apply to a late tax return itself and for late payment, in the same way as under standard Self Assessment.

From the 2027/28 tax year, a points-based system will apply to late quarterly updates. Each late submission adds a penalty point, and once you reach a threshold of four points, HMRC will issue a fixed penalty of £200. Further £200 penalties can apply for each additional late submission once the threshold is reached, until your points reset through a period of on-time filing.

As these rules are still being phased in, it's worth checking HMRC's latest guidance closer to the 2027/28 tax year to confirm exactly how the threshold and reset period will work in practice.

Do You Have a Reasonable Excuse?

HMRC may accept a reasonable excuse for filing late, such as a serious illness, a family bereavement, or unexpected and unavoidable circumstances. If you think this applies to you, you'll usually need to appeal in writing and provide supporting evidence.

It's important not to assume a reasonable excuse will automatically be accepted. HMRC reviews each case individually, so it's best to get advice if you're relying on this.

How to Avoid Late Filing Penalties

The simplest way to avoid penalties is to start early rather than leaving your tax return until January. Gathering your income and expense records throughout the year, rather than scrambling at the last minute, makes the whole process far less stressful.

If you're filing for the first time, make sure you've registered for Self Assessment in good time too, as this has its own deadline. If you're still waiting for information close to the deadline, seek professional advice rather than simply allowing the filing deadline to pass. In some circumstances, provisional figures may be appropriate, but they should be used and disclosed correctly.

Key Facts You Should Know

Payment deadlines and penalties are separate from filing penalties, so both need attention.

Why Choose Taxeezy?

Late penalties are one of the easiest tax problems to avoid with the right preparation. At Taxeezy, we help freelancers, sole traders, landlords and individuals prepare and submit accurate tax returns well ahead of the deadline.

Our online service makes filing simple: you provide your information, a dedicated tax professional prepares your return, and we submit it to HMRC on your behalf, so you don't have to worry about missing a deadline or facing an avoidable penalty.

Whether you're filing for the first time or have missed a deadline before, our team is here to help you get back on track and stay compliant, without the stress.