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Posted on • Originally published at landolio.com

The actual cost of missing the MTD deadline (it is not just £100)

MTD for Income Tax kicks in 6 April 2026. Six days.

Most freelancers know there is a penalty. Most think it is £100. They are wrong.

The penalty structure nobody reads

Late filing:

  • 1 day late: £100
  • 3 months late: £10/day (up to £900)
  • 6 months late: additional £300 or 5% of tax due (whichever is higher)
  • 12 months late: another £300 or 5%

Late payment:

  • 30 days late: 5% of unpaid tax
  • 6 months: another 5%
  • 12 months: another 5%

So if you owe £5,000 and ignore it for a year, you are looking at £100 + £900 + £300 + £300 + £750 + £750 + £750 = £3,850 in penalties alone. On top of the £5,000.

That is a 77% surcharge for procrastination.

What MTD actually requires

From 6 April 2026, if your self-employment or property income exceeds £50,000, you must:

  1. Use compatible software to keep digital records
  2. Send quarterly updates to HMRC (not annual — quarterly)
  3. Submit a final declaration instead of a Self Assessment return

If your income is between £30,000 and £50,000, you have until April 2027. Under £30,000, TBD.

The bit nobody talks about: quarterly submissions

This is the real change. You cannot just do one mad January scramble any more. You need to report:

  • Q1: 6 April – 5 July (due 7 August)
  • Q2: 6 July – 5 October (due 7 November)
  • Q3: 6 October – 5 January (due 7 February)
  • Q4: 6 January – 5 April (due 7 May)

Miss a quarterly update? That is a separate penalty point. Rack up enough points and you get fined.

What to actually do this week

If you are a UK freelancer earning over £50k:

  1. Check your software — does it support MTD ITSA? Most accounting packages are adding it now
  2. Get your records digital — no more shoeboxes of receipts
  3. Know your first quarterly deadline — Q1 update due 7 August 2026
  4. Calculate your day rate properly — use a day rate calculator to make sure your rate covers the admin overhead
  5. Sort your late payment process — if clients pay late, you cannot file on time. Use a late payment interest calculator to know what you are owed

Free resources

I have been building tools for exactly this situation:

If you want the full breakdown in one place, Landolio has a Self-Assessment Recovery Kit (£9) that walks through the whole process.

Six days. Do not be the person paying £3,850 in penalties because you "meant to get round to it".


What is your MTD setup looking like? Sorted or scrambling?

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