Making Tax Digital for Income Tax: every deadline a UK practice needs in 2026

Making Tax Digital for Income Tax is the biggest change to Self Assessment in a decade, and the first hard deadline lands on 7 August 2026. If your firm files for sole traders or landlords, here is exactly who is affected, every date that now repeats each year, and what it does to your workload.

Who has to use it, and when

Mandation is phased by income. HMRC reviews each person’s Self Assessment return and uses the prior year’s figures to decide who is in scope. The threshold falls every year, so a client who is safe in 2026 can be pulled in by 2027 or 2028.

The number that matters is qualifying income: the total gross income from self-employment and property, added together, before any expenses, taken from the previous year’s return. Not profit, turnover. HMRC estimates around 864,000 sole traders and landlords are in this first wave. Partnerships come later, on a timeline HMRC has not yet set.

HMRC writes to people it believes are in scope, but the responsibility to check sits with the taxpayer, which in practice means it sits with you. The firms that get ahead of this are the ones segmenting their client list by qualifying income now, so they know their 2026, 2027 and 2028 waves before the letters land.

What actually changes for a client

Less than the panic suggests, but enough to reshape a year. The annual cycle of one return stays. Bolted on top of it are quarterly updates and a digital record-keeping requirement.

A quarterly update is a summary, not a mini tax return: running totals of income and expenses, generated by the software from the digital records. HMRC does not provide that software, so every affected client needs a compatible product (or bridging software over their spreadsheets) in place before the year starts.

The four deadlines that now repeat every year

For a standard accounting period ending 5 April, the updates fall one month and seven days after each quarter. That gives four fixed dates that will repeat every year from now on: 7 August, 7 November, 7 February and 7 May. Clients who elect calendar quarters (period ending 31 March) keep the same submission dates. The year-one timeline at the top of this page lays all of it out, from records starting in April to the return due by 31 January 2028.

Year one is a soft landing, but only year one

HMRC has confirmed it will not apply penalty points for late quarterly updates in the 2026 to 2027 tax year. That is genuine breathing room, but read it carefully: you still have to send every update before the client can submit their return, late payment penalties still apply, and the relief is for the first year only. A new points-based penalty regime replaces the old late-filing penalties after that, where points accumulate until they tip into a fine.

What this does to a practice

Here is the part the headlines miss. A client who used to generate one filing event a year now generates five: four quarterly updates and the final return. The fee is similar. The number of times you have to collect records, chase a non-responsive client, review figures and submit is four times higher.

Now multiply that by the share of your client base over £50,000 in 2026, add the £30,000 band in 2027, then the £20,000 band in 2028. The bottleneck was never the filing itself. It is collecting clean records from hundreds of clients, four times a year, without quadrupling headcount.

How to get ahead of it

• Segment the client list now. Tag every client by qualifying income so you know your 2026, 2027 and 2028 waves before HMRC tells you.
• Move clients onto compatible software early. The worst time to onboard software is the week before a deadline.
• Build the chasing capacity, not just the filing capacity. The work that scales badly is the document collection and the follow-ups, not the submission.

That last point is the whole game, and it is exactly what a purpose-built tracking and chasing system is for: knowing which client owes which quarter’s records, and nudging them automatically, so four filing events a year do not become four times the manual chasing. It is the problem we built Quill around. If you are deciding whether to buy a tool for that or build your own, we weigh it up in build vs buy.