MTD ITSA First Quarter Starter Kit

If your first Making Tax Digital quarterly update — covering 6 April to 5 July 2026 — is due by 7 August 2026 and you haven't started, 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, with a live countdown to 7 August 2026
• 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.