Missed an MTD Deadline? Penalties and What to Do Next

So You've Missed an MTD Deadline - What Actually Happens?

Missing a Making Tax Digital deadline feels awful. Whether you forgot the date, had a difficult few weeks, or simply didn't realise a quarterly update was due, the first question that usually follows is: how bad is this? The honest answer is that the consequences depend on what you missed, how late you are, and whether you have a reasonable excuse. This guide explains the actual penalty system in plain English, what HMRC charges in interest, and the concrete steps you should take right now to limit the damage.

The Two Things You Can Miss Under MTD

Under Making Tax Digital for Income Tax (MTD ITSA), there are two types of filing obligation:

• Quarterly updates - you submit your income and expenses four times a year, roughly every three months.
• The final declaration - this is filed once a year by 31 January following the end of the tax year. It confirms your total income, claims any additional allowances, and replaces what used to be called a Self Assessment tax return.

Missing either carries different consequences, so it matters which one you've missed. If you're unsure what each involves, this post explains the difference between quarterly updates and the final declaration in practical terms.

How the MTD Penalty System Works

HMRC uses a points-based penalty system for late quarterly updates. This is different from the old flat-fine approach most people remember from paper tax returns.

Points for late quarterly updates

Every time you miss a quarterly update deadline without a reasonable excuse, HMRC adds one late-filing penalty point to your account. Points accumulate over time. Once you reach a threshold, a flat financial penalty is charged.

• For quarterly filers (which MTD ITSA requires), the penalty threshold is 4 points.
• When you hit 4 points, HMRC charges a £200 penalty.
• Every subsequent late filing after that threshold also attracts a £200 penalty.

So one missed quarterly update does not immediately result in a fine. You accrue a point, and if you stay on top of things going forward, that point can eventually drop off your record. HMRC will notify you when points are added.

Penalties for the final declaration

The final declaration is treated differently. It is subject to the same penalty structure as the current Self Assessment tax return system - meaning a fixed £100 penalty applies immediately if you file even one day late, with further charges building up after three months, six months, and twelve months.

Here is what that looks like:

1. Day 1 late: £100 automatic penalty.
2. After 3 months: daily penalties of £10 per day, up to a maximum of £900.
3. After 6 months: an additional 5% of the tax owed, or £300 - whichever is higher.
4. After 12 months: another 5% of the tax owed, or £300 - whichever is higher.

These are the filing penalties. They are separate from any penalties for paying your tax bill late.

For a fuller breakdown of all the penalty types, our MTD penalties guide covers each scenario.

Interest on Unpaid Tax

Penalties are one thing. Interest is another, and it runs separately from any filing penalties.

If you owe tax and don't pay it by the deadline (31 January for any balance you owe for the previous tax year), HMRC charges interest on the unpaid amount. As of 2025, that rate is the Bank of England base rate plus 2.5 percentage points. It compounds daily.

Even if HMRC waives a filing penalty (for example, if you have a reasonable excuse), interest on unpaid tax is rarely waived. You will still owe it.

What Is a Reasonable Excuse?

HMRC will not apply a penalty - or will cancel one that has been applied - if you have a reasonable excuse for missing the deadline. This is not a vague get-out clause. HMRC has specific views on what counts, and what doesn't.

What HMRC generally accepts

• A serious or unexpected illness that prevented you from filing.
• The death of a close family member or partner shortly before the deadline.
• A technical failure of HMRC's own systems (not your broadband or a software issue on your end).
• A fire, flood, or other disaster that destroyed your records.
• Delays in receiving information you needed from a third party, where you made every reasonable effort to get it in time.
• Being in hospital or receiving care that prevented access to your records.

What HMRC does not accept

• Forgetting the deadline.
• Being too busy.
• Assuming your accountant or agent had filed on your behalf (even if they told you they would).
• Finding the software confusing.
• Saying you didn't know about MTD or the obligations.
• Having a deadline fall at an inconvenient time of year.

The key test HMRC applies is: was there something genuinely out of your control, and did you act as soon as it was reasonable to do so once that obstacle was removed?

Real-world examples

Example 1 - accepted: A sole trader was admitted to hospital for surgery two days before the Q2 deadline and was discharged ten days later. She filed within three days of getting home and wrote to HMRC explaining what happened. HMRC accepted this as a reasonable excuse and cancelled the point.

Example 2 - not accepted: A landlord missed the Q3 deadline because he had a very busy period managing a property renovation and simply didn't get round to it. HMRC treated this as not having a reasonable excuse. A point was added to his record.

Example 3 - borderline: A freelancer had severe mental health difficulties for several months and was unable to manage financial admin. HMRC can accept this, but it typically requires evidence - such as a doctor's letter - and the individual needs to have filed as soon as they were able.

If you believe you have a reasonable excuse, you need to appeal the penalty. Don't assume HMRC will figure it out themselves.

We have a separate post on MTD exemptions and reasonable excuse that covers the appeal process in more detail.

What to Do Right Now If You've Missed a Deadline

The single most important thing is to act quickly. Every day you wait makes the situation harder to recover from - both in terms of interest and in terms of HMRC's assessment of whether you responded reasonably.

Step 1 - File as soon as possible

Whether it's a quarterly update or a final declaration, file it now. Even filing a day late is better than filing a week late. The quarterly update itself does not have to be perfect - HMRC accepts reasonable estimates if you're missing some figures, and you can amend a quarterly update after filing if needed. Getting something in is nearly always better than waiting until everything is perfect.

Step 2 - Pay any tax you owe

If your missed deadline includes unpaid tax, pay it. Even a partial payment reduces the interest you'll accumulate. You can pay HMRC directly through your Government Gateway account or via bank transfer.

Step 3 - Check your penalty points

Log into your HMRC online account and check whether a point has been added. HMRC should notify you, but it's worth confirming. If you've already hit the 4-point threshold and received a £200 fine, make sure you know what you're dealing with before deciding whether to appeal.

Step 4 - Appeal if you have reasonable grounds

If you believe you have a reasonable excuse, submit an appeal. You can do this through your HMRC online account or in writing. State the facts plainly, include any supporting evidence (letters, medical documents, screenshots of HMRC system errors), and make it clear you acted as quickly as you reasonably could once the obstacle was removed.

If HMRC issues a penalty notice, you have 30 days to appeal. Don't miss that window.

Step 5 - Get your records in order before the next deadline

Once the immediate problem is resolved, take stock. If you missed a deadline because your record-keeping wasn't working, that needs fixing before the next quarter. A missed deadline is often a symptom of disorganised records rather than the underlying cause.

Our post on setting up a record-keeping system for MTD is a practical starting point.

How to Clear Penalty Points

Points don't stay forever, but they don't disappear automatically just because time passes. To have your points reset to zero, you need to:

• File all required quarterly updates and your final declaration on time for a continuous period of 24 months.
• After that clean 24-month period, any accumulated points are removed.

This means if you currently have 3 points and miss another deadline, you hit the £200 threshold and start accruing financial penalties on top. The incentive to stay current is real.

If HMRC's Systems Were at Fault

Occasionally, HMRC's own MTD service goes down or returns errors during a filing window. If this happens close to a deadline, it is a legitimate reason to miss that deadline - but you need to document it. Take screenshots, note the date and time, and file as soon as the system is back. HMRC does issue guidance when known service issues affect deadlines.

We cover this scenario in more detail in what to do if HMRC's MTD service is down.

Landlords and Multiple Income Sources

If you're a landlord who also has self-employment income, your obligations under MTD may be more complex. You may need to file separate quarterly updates for each income source, which means more deadlines - and more ways to accidentally miss one.

The penalty points system applies per obligation type. Missing a quarterly update for your self-employment counts separately from missing one for your property income.

If you're managing both income sources under MTD, this guide on multiple income sources explains how the obligations interact.

When Should You Get Professional Help?

Most people can handle a single missed quarterly update themselves - file late, check your points, consider an appeal if you have good grounds. But if:

• You've missed multiple deadlines and your points are at or near threshold
• You have unpaid tax going back more than one quarter
• You've received a formal penalty notice and are unsure whether to appeal
• HMRC has opened a compliance check following missed deadlines

...then it's worth speaking to a tax adviser or accountant. Not because the situation is necessarily catastrophic, but because the appeal process and negotiations with HMRC become more consequential once significant penalties are involved. For context on what a compliance check looks like, see what to expect from an HMRC compliance enquiry.

Preventing the Next Missed Deadline

The simplest way to avoid this situation again is to know your dates and have a system that doesn't rely on memory. The four quarterly update deadlines for the 2026-27 tax year are:

• 7 August 2026 (for the quarter ending 5 July)
• 7 November 2026 (for the quarter ending 5 October)
• 7 February 2027 (for the quarter ending 5 January)
• 7 May 2027 (for the quarter ending 5 April)

The final declaration is due by 31 January 2027 for the 2026-27 tax year.

Set calendar reminders at least two weeks before each deadline. Keep records updated monthly, not in a panic the week before. And use software that makes filing the actual quarterly update a 15-minute job rather than a stressful afternoon.

The complete MTD quarterly deadlines for 2026-27 are all in one place if you want to add them all at once.

To Summarise

Missing an MTD deadline is stressful, but the system is designed with some recovery room built in. One missed quarterly update earns a point, not an immediate fine. The fine kicks in at 4 points. The final declaration follows a stricter, immediate-penalty structure. Interest on unpaid tax runs regardless of filing status. If you have a genuine reasonable excuse, you can appeal - but you need to act quickly and document it. The recovery path is straightforward: file now, pay what you owe, appeal if you have grounds, and put a better system in place before the next deadline arrives.