MTD ITSA First Quarter Starter Kit

Please note: this kit covers Quarter 1 of 2026/27 only (6 April to 5 July 2026). That update was due by 7 August 2026, so this kit is for catching up a late first update. For the rest of the tax year, use the full MTD ITSA Quarterly Tracker.

If you still haven't sent your first Making Tax Digital quarterly update, this small Excel kit gets it done in an afternoon. It's deliberately narrow: no year-long system to learn, just one clean log for income and expenses, a summary of what to submit, and a plain-English guide to sending it to HMRC.

The five tabs include:

• Start Here, showing the 7 August 2026 deadline, the days since it passed and a status line
• A Quarter 1 Log where each row is flagged with an 'In Quarter 1?' column so stray dates from March or July can't skew the numbers (refunds are entered as negatives, and a 'Disallowable' category keeps things like fines out of your tax figures)
• A Quarter 1 Summary showing the three headline figures HMRC's quarterly update wants, plus a full SA103S box breakdown
• A What To Do Next page explaining bridging software and HMRC's official software finder

Every SA103S box is mapped against HMRC's published form, and the maths is checked against a 35-transaction worked example covering the tricky boundary dates, refunds and disallowable costs — hand-calculated, then independently re-checked. 18 of 18 QA checks pass, shown on the file's QA & Version tab.

This is a record-keeping tool, not tax advice and not HMRC-recognised filing software. When you're ready for the full year, the shop's full MTD ITSA Quarterly Tracker picks up where this leaves off.