The two tests
You have to register if you fail either test — and the forward-look one is the surprise:
- Backward look — taxable turnover over the last 12 months goes above £90,000. Register within 30 days of the end of that month.
- Forward look — you expect to exceed £90,000 in the next 30 days alone (a single big contract, say). Register immediately, effective from the day you knew.
It's rolling, not annual
Coming back down
Once registered, you can apply to deregister only when taxable turnover drops below £88,000.00 — deliberately lower than the registration line so a business near the threshold isn't flipping in and out month to month.