MTD vs Self Assessment: What's Different?

If you've filed Self Assessment returns before, the biggest mindset shift with MTD isn't the paperwork itself — it's the rhythm. Here's how the new annual process compares to what you're used to, and what changes between MTD vs Self Assessment.

The old way

Under traditional Self Assessment, you gather a full tax year's income and expenses together - often in the weeks before the 31 January deadline - and submit a single return (typically the SA100, plus supplementary self-employment for your photography business and any other pages) summarising the whole year at once.

The MTD way

Under MTD, that single annual return is replaced by two things working together:

• The four quarterly updates through the year, which build up a running picture of your income and expenses

• A Final Declaration (also known as the tax return) at the end of the tax year, due by the same 31 January deadline, which confirms your full-year figures are correct and complete, adds any income not already captured by your quarterly updates, and finalises your tax position for the year

Rather than one large exercise done from scratch, the year-end process becomes a case of reviewing and confirming figures that have already largely been reported.

What's added at the final tax return stage

Some information is pre-populated by HMRC based on other records it holds - employment income taxed through PAYE, pensions, state benefits, and certain capital gains. You (or Viewfinder Accounting, on your behalf) need to add anything not already captured, most commonly:

•        Savings interest

•        Dividends

•        Partnership profit shares

•        Any other income not reported through your quarterly updates.

The transition year (the change from MTD vs Self Assessment)

One detail worth flagging: the tax year immediately before you're mandated into MTD is still filed as a traditional, full Self Assessment return. MTD reporting only begins from the following 6 April. So if you're due to join from 6 April 2027, your 2026–27 return is still filed the old way. Even though you are now in MTD from 6 April 2027 (in this example), and submitting your data quarterly, your Self Assessment tax return for the year ended 5 April 2027, will not be due until 31 January 2028. Understanding these overlapping deadlines is vital to avoid unexpected penalties.

How Viewfinder Accounting Can Help

The move from one big annual return to a mix of quarterly updates and a final declaration is a genuine change of process, not just a change of software. Viewfinder Accounting manages the whole cycle for photography clients - recordkeeping, quarterly updates and the year-end final declaration, so nothing is left to a January scramble.