MTD quarterly update: what it actually contains (and what it isn't)

What it contains

• Total business income for the period.
• Allowable expenses, totalled by category — the standard self-employment (or property) categories, not a line-by-line transaction list.
• Usually reported cumulatively (year-to-date) — each quarter's figures build on the last.

That's it. No receipts attached, no tax calculated, no other income. The categories match how you should already be logging expenses — see allowable expenses.

What it is NOT

• Not a tax return. No tax is calculated or owed at a quarterly update.
• Not a payment. Your payment dates are unchanged (31 January, plus payments on account if they apply).
• Not final. Figures roll forward and are corrected; the final declaration (31 January) is the definitive one.
• Not everything about your tax. Reliefs, allowances and non-business income come in at the final declaration, not each quarter.

Quarterly update vs final declaration

Think of the four quarterly updates as keeping HMRC roughly in the picture through the year, and the final declaration as the once-a-year settle-up that replaces the old Self Assessment return. The quarters are summaries; the final declaration is where the tax is worked out. For the calendar of what's due when, see the deadlines & penalties guide or run the deadline checker.

Why the habit beats the software

If your income and expenses are logged and categorised as you go, a quarterly update is a few totals your software already has. The whole difficulty of MTD is having something accurate to summarise each quarter — which is a record-keeping habit, not a software feature. See the MTD for Income Tax checklist.

FAQ

What information goes into a quarterly update?

Totals of your business income and allowable expenses for the period, grouped by category, sent from HMRC-recognised software. Most software reports cumulative (year-to-date) figures each quarter. You are not sending every transaction or attaching receipts — just the category totals.

Is a quarterly update a tax return?

No. It's a periodic summary, not a return and not final. Your return-equivalent is the final declaration after the tax year (due 31 January), which pulls the year together, adds anything else, and is where the tax is actually worked out.

Do I include things like personal allowance or other income?

Not in the quarterly updates — those are business-source summaries. Reliefs, allowances, and other income (employment, savings, dividends) come together at the final declaration, not each quarter.

What if I get a quarterly figure wrong?

It corrects forward. Because most software reports cumulatively, a later quarter's totals supersede earlier ones, and the final declaration is the definitive figure. Quarterly updates are designed to be adjustable, not perfect first time.