08/10/2026
If you sell online and your sales are getting close to £90,000 a year, November is the month to watch.
The VAT threshold is checked on a rolling 12 months at every month end, not on the tax year. A quiet November last year dropping out and a Black Friday November coming in can take you over in a single month.
In our worked example, a seller goes from £78,000 at the end of October to £93,000 at the end of November. HMRC has to be told by 30 December 2026, and registration starts on 1 January 2027.
If VAT is not charged on sales after the date registration should have started, HMRC treats the prices as including VAT, so one sixth of the gross is due anyway.
Full guide and a checklist for the run-up to Black Friday in the first comment.