VAT Registration: When You Must Register, and When You Should Not
The £90,000 threshold is a rolling 12-month test, not a tax-year one — which is how most businesses miss it. What triggers registration, what it costs you, and when voluntary registration pays.
Most businesses do not decide to register for VAT — they discover they should have registered some months ago. The test is not the one people assume, and getting it wrong is expensive because the VAT is owed whether or not you ever charged it.
The rolling 12-month test
You must register when VAT-taxable turnover exceeds £90,000 in any rolling 12-month period. Not your accounting year. Not the tax year. At the end of every month, look back over the previous twelve.
A business turning over £8,000 a month crosses £90,000 partway through its second year, and the month it happens has nothing to do with its year end. This is the single most common way businesses end up registered late.
The forward look
There is a second trigger. If you expect turnover to exceed £90,000 in the next 30 days alone — a single large contract will do it — you must register immediately, and the registration is effective from the date you formed that expectation, not from when the money arrives.
Deadlines
| Trigger | Register by | Effective from |
|---|---|---|
| Rolling 12 months exceeded | 30 days after the end of that month | The first day of the second month after you went over |
| Expect to exceed in 30 days | End of that 30-day period | The date you realised |
What registration actually changes
- You add 20% to your prices, or absorb it. For consumer businesses this is effectively a price rise.
- You reclaim VAT on purchases, which is why it can suit businesses that buy a lot.
- You file VAT returns, usually quarterly, through Making Tax Digital compatible software.
- Your record keeping has to be good enough to support both sides of every return.
When voluntary registration pays
You can register below the threshold. It is worth it when your customers are VAT-registered businesses that reclaim the VAT anyway, when you buy a lot of standard-rated goods and services, or when your sales are zero-rated so you reclaim input VAT without charging output VAT.
It is usually a bad idea when you sell to the public and your competitors are not registered: you become 20% more expensive overnight for no benefit.
If you are already over
Register now and tell HMRC yourself. A voluntary disclosure carries a far lower penalty than being found. Work out the VAT owed from the date registration should have started — for sales you have already made, this comes out of your own margin unless customers will accept a VAT-only invoice.
Getting help with this
AJH Accountants handles VAT and small business accounting for clients across the UK. We file the return, tell you what you can claim, and deal with HMRC on your behalf, so nothing depends on you remembering a deadline.
See how our VAT and small business accounting service works, or send us a quotation request and we will call you back. You can also call the office on 01204 840303.
Originally published at ajhaccountant.co.uk/blog/vat-registration-threshold-when-to-register.