MTD quarterly submissions: a step-by-step guide for Brighton businesses

Making Tax Digital for Income Tax replaces the annual Self Assessment return with four quarterly submissions per year, plus a final year-end declaration. If you are new to MTD, the process can look daunting — but in practice it is straightforward once you understand how it works.

This guide walks through exactly what a quarterly submission involves, when the deadlines are, and what happens if you miss one.

What is a quarterly submission?

A quarterly submission (officially called a "quarterly update") is a summary of your income and expenses sent to HMRC through MTD-compatible software every three months. It is not a tax payment and does not trigger a tax demand — it simply keeps HMRC informed of your trading or rental position throughout the year.

At the end of the tax year, you submit a final declaration that confirms all your income, claims any reliefs or allowances, and calculates your final tax liability. This is broadly equivalent to the current Self Assessment return.

The four quarterly deadlines

The tax year runs from 6 April to 5 April. The four quarterly periods and their submission deadlines are:

• Quarter 1: 6 April – 5 July → submit by 5 August
• Quarter 2: 6 July – 5 October → submit by 5 November
• Quarter 3: 6 October – 5 January → submit by 5 February
• Quarter 4: 6 January – 5 April → submit by 5 May

The final declaration must be submitted by 31 January following the end of the tax year — the same deadline as the current Self Assessment return.

What goes into a quarterly submission?

Each quarterly update includes a summary of your income and allowable expenses for that period. For self-employed individuals, this covers business income and expenses under the relevant expense categories. For landlords, it covers rental income and property expenses.

You do not submit individual invoices, receipts, or bank statements to HMRC — only the totals within each category. However, you must keep the underlying digital records and be able to produce them if HMRC asks.

What software do you need?

HMRC requires you to use software that is approved for MTD for Income Tax. The software connects directly to HMRC's systems and submits updates on your behalf. You cannot submit quarterly updates manually through the Government Gateway.

The most widely used options are Xero, QuickBooks, and FreeAgent. See our MTD software comparison for Brighton businesses to find the right one for your situation.

What are the penalties for missing a submission?

HMRC operates a points-based penalty system for late MTD submissions. Each missed quarterly submission or late final declaration earns a penalty point. When you accumulate enough points, a financial penalty of £200 is charged and the points reset.

The threshold before a penalty fires depends on how frequently you submit — for quarterly submitters, the threshold is four points. Points expire after 24 months if no further defaults occur.

How Fitzpatrick Co manages this for you

If you are on a Fitzpatrick Co retainer, we handle every quarterly submission on your behalf. We review your records each quarter, prepare the update, and submit it before the deadline — with no action required from you other than keeping your receipts and invoices up to date in the software we set up for you.

We also flag any planning opportunities during the year, so you are not left with a tax bill surprise in January.

Frequently asked questions