You need to register for VAT when your taxable turnover goes over £90,000 in any rolling 12-month period, or when you expect it to go over £90,000 in the next 30 days alone. Once you cross the line, you have 30 days from the end of that month to tell HMRC. So when do you need to register for VAT in practice, and what happens if the deadline slips? This guide walks through the two tests, the deadlines, the penalties and the first weeks as a VAT-registered business.
Key takeaways
HMRC applies two separate VAT registration tests, and either one on its own can trigger compulsory VAT registration.
If you are looking at how to register for VAT self-employed, the same compulsory registration tests apply to sole traders as they do to other businesses.
Add up your taxable turnover for the last 12 months at the end of every month. If that rolling total goes over £90,000 for the first time, the clock starts. This is the test that catches most growing businesses, because turnover builds gradually and the 12-month window keeps moving.
If at any point you have reasonable grounds to expect more than £90,000 of taxable turnover in the next 30 days alone, a single large contract, for example, you must register by the end of that 30-day period. Your effective date is the date you realised, not the date you invoiced, so this test bites immediately.
A simple example shows the difference. A consultant wins a £100,000 contract on 1 May. Test 2 applies: the application must reach HMRC by 30 May, and the effective date is 1 May. Without that contract, the same consultant drifting over £90,000 on a rolling 12-month view gets the gentler Test 1 timetable below.
The VAT registration threshold sits at £90,000 of taxable turnover and stays there for 2026/27. Taxable turnover means the total value of everything you sell that is not VAT-exempt or out of scope, including:
If you only sell VAT-exempt or out-of-scope goods and services, you do not have to register at all. Zero-rated sales do count toward the threshold, but a business selling almost entirely zero-rated goods can apply for an exemption from registration rather than registering.
The timing rules are mechanical, and HMRC applies them exactly.
A web design studio tracks its rolling 12-month turnover at each month end: £88,200 at the end of June, £91,400 at the end of July. It crossed the threshold in July. The deadline to notify is 30 August (30 days after the end of July), and the effective registration date is 1 September. From 1 September, every invoice carries 20% VAT.
One useful escape hatch: if turnover goes over the threshold temporarily, you can apply to HMRC for a registration exception. HMRC reviews it and either confirms the exception in writing or registers you anyway.
Yes. You can voluntarily register for VAT while your taxable turnover is below £90,000, and doing so can sometimes make commercial sense:
The downside is real: you file returns, keep digital records and hand over VAT on your sales that previously stayed in the business. For consumer-facing businesses, adding 20% to prices (or absorbing it) hurts. The decision needs numbers, not instinct, and a short cost-benefit review answers it.
Late registration hurts twice.
First, the cash. You owe VAT on all sales back to your correct effective date. Because you did not charge it at the time, that money comes out of your own pocket; you cannot usually reopen old invoices to customers.
Second, the penalty. HMRC charges a failure-to-notify penalty as a percentage of the VAT due from the date you should have registered. The bands reward telling HMRC first: an unprompted disclosure keeps you at the bottom of the range, while a non-deliberate failure to notify more than 12 months late sits in a 20% to 30% band even when you disclose before HMRC opens a check. Delay costs percentage points on top of the VAT itself.
Registration changes how the business runs day to day:
Most registrations take a few working days to process, and HMRC posts your VAT number and confirmation of the effective date.
Can you deregister if turnover drops?
Yes. If your taxable turnover falls below £88,000, you can ask HMRC to cancel your VAT registration. You must cancel within 30 days if you stop being eligible, for example if you stop trading.
Do zero-rated sales count toward the £90,000?
Yes. Zero-rated sales are taxable sales, so they count. A business selling almost entirely zero-rated goods can instead apply for an exemption from registration, which needs HMRC’s permission.
What if turnover spikes once and then falls back?
You can apply for a registration exception. HMRC reviews it and either confirms the exception in writing or registers you anyway, so apply rather than assume.
Do you have to register if you only sell exempt services?
No. Businesses selling only VAT-exempt or out-of-scope goods and services do not have to register, although the partial exemption rules around mixed sales deserve care.
You generally need to register and account for VAT if your taxable turnover exceeds the £90,000 registration threshold, or if you expect it to exceed £90,000 in the next 30 days alone. Below the threshold, you may still choose to register voluntarily.
Apex Accountants handles VAT registration end to end: we check which of the two tests applies to you, calculate your rolling turnover properly, set the effective date correctly and file the application. For businesses already past the threshold, we manage late registration with HMRC, including penalty mitigation, and bring your VAT filings up to date. Below the threshold, we run the voluntary registration cost-benefit numbers before you commit.
Our VAT services also cover ongoing compliance, return preparation and support with more complex VAT issues. We can set up your Making Tax Digital software and provide outsourced accounting support to keep your records accurate and your first return on track.
Contact us today to discuss your turnover, registration position and next steps with our team.
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