Direct answer: You must register for VAT if your taxable turnover goes over £90,000 in any rolling 12-month period, or if you expect it to pass £90,000 in the next 30 days alone. Below that, registration is usually optional — unless you choose to register voluntarily.
VAT is one of those thresholds that catches growing small businesses by surprise. Nobody sends you a letter to say you have crossed the line — HMRC expects you to spot it yourself, month by month. Miss it and you can end up paying VAT out of your own pocket on sales you already made. This guide gives you the five checks that settle the question, with worked figures.
The two tests that decide it
There are two separate tests, and either one on its own can make registration compulsory:
- The backward test — the last 12 months. At the end of every month, add up your taxable turnover for the previous 12 months. If that rolling total is over £90,000, you must register. You then have 30 days from the end of that month to tell HMRC, and your registration takes effect from the first day of the second month after the month you crossed the line.
- The forward test — the next 30 days. If you expect your taxable supplies to pass £90,000 in the next 30 days alone — for example, because you have just won one very large contract — you must register at once, before that 30-day period ends. You do not wait for the sales to happen first.
The backward test is the one most people miss, because it is not tied to the tax year or your accounting year — it slides forward by one month, every month. Checking once a year, when your accounts are done, is far too late.
| VAT rule for 2026/27 | Figure or deadline |
|---|---|
| Registration threshold | £90,000 of taxable turnover in any rolling 12 months |
| Forward-looking test | More than £90,000 expected in the next 30 days alone |
| Deadline after crossing the threshold | Within 30 days of the end of the month you went over |
| When registration takes effect | First day of the second month after you crossed the line |
| Deregistration threshold | £88,000 — you may apply to cancel below this level |
| VAT rates | 20% standard, 5% reduced, 0% zero-rated |
What counts as taxable turnover?
Taxable turnover is the total value of everything you sell that is not exempt from VAT and not outside the scope of UK VAT. That includes sales at the standard rate, the reduced rate and the zero rate. This is where many owners go wrong: zero-rated sales still count towards the £90,000, even though you charge 0% VAT on them. A business selling mostly zero-rated food or children’s clothes can therefore cross the threshold without ever charging a penny of VAT.
What does not count is exempt income — for example, most insurance, and some education and health services — and sales outside the scope of UK VAT. Two more points matter. First, the test is on turnover, not profit: a business with £95,000 of sales and only £15,000 of profit must still register. Second, VAT registration belongs to the person, not to each business: a sole trader running two trades must add both together, and a business selling across several websites or marketplaces must add every channel together.
If you are based outside the UK, there is no £90,000 threshold at all: you must register from your first taxable sale in the UK. The rest of this guide is for UK-based businesses, who do get the threshold.
5 checks that settle it for your business
Work through these in order. If any of the first two checks gives you a “yes”, registration is compulsory. The other three stop the common mistakes.
Check 1: Add up your last 12 months. At the end of this month, total your taxable sales for the last 12 complete months. Not this tax year, not this calendar year — the last 12 months, ending now. If the total is over £90,000, you must register, and the 30-day clock is already running.
Check 2: Look ahead 30 days. Do you have orders, contracts or a single deal in the next 30 days that would push your taxable supplies over £90,000 on their own? If so, register now, before that period ends. Waiting for the money to land is the mistake.
Check 3: Separate taxable from exempt. Split your sales into taxable (standard, reduced and zero-rated) and exempt or out-of-scope. Only the taxable side counts towards £90,000. If you are unsure whether something is exempt, check before you rely on it.
Check 4: Add every trade and channel together. Add up all your taxable sales: every shop, website, marketplace and side trade run by the same person. If you run two small trades each turning over £50,000, your combined £100,000 is over the threshold even though neither trade is over it alone.
Check 5: Check whether you are already over. If you have not been checking monthly, work backwards now and find the first month-end at which your rolling total passed £90,000. That is when your obligation started, even if you only discover it today. Registering late does not erase the VAT due from your correct registration date.
Worked example: crossing the line in September
Take a freelance designer whose taxable sales for the 12 months to 30 September 2026 total £92,300. She has crossed the threshold, so she must tell HMRC by 30 October 2026, and her registration takes effect on 1 November 2026. VAT is due on her sales from 1 November onwards — not on the £92,300 that took her over the line, and not on October’s sales. That gap between crossing and taking effect is genuinely useful: it gives her a few weeks to tell clients, reprice her work and set up VAT-ready invoicing.
The pricing question matters just as much as the date. Suppose she charges £100 for a job before VAT. Once registered, she must either charge £120 (£100 plus 20% VAT) or keep the price at £100 and absorb the VAT herself — in which case £83.33 is her income and £16.67 is VAT owed to HMRC. For business customers who are VAT-registered themselves, the £120 price usually causes no problem, because they reclaim the VAT. For ordinary consumers, that £20 jump is real, and it is why the decision feels very different depending on who you sell to.
Should you register voluntarily, before you have to?
Voluntary registration can pay off, but only for the right business. It usually makes sense if most of your customers are VAT-registered businesses, because they can reclaim the VAT you charge, while you reclaim the VAT on your own costs — stock, equipment, software and fees. It can also make sense if you have large one-off costs coming up, such as fitting out a shop.
It usually does not pay off if you sell mainly to consumers or to small unregistered businesses, because a 20% price rise can lose you sales, and the admin — digital records, quarterly VAT returns and Making Tax Digital software — is real work for a small return. You can only deregister once your taxable turnover falls below £88,000, and deregistration is something you apply for, not something that happens automatically.
For the full picture of the rates and the registration process itself, read our guide to VAT registration in the UK, and check GOV.UK’s register for VAT guidance before you apply.
Make it a monthly habit
The cheapest protection against a late-registration bill is a five-minute check at the end of every month: total your last 12 months of taxable sales and compare the figure with £90,000. Set a warning line at £80,000 — when you pass it, start planning prices, invoicing and software, so registration is a calm decision rather than a rush.
Frequently asked questions
What is the VAT registration threshold for 2026/27?
£90,000 of taxable turnover in any rolling 12-month period, unchanged since 1 April 2024. You must also register if you expect to pass £90,000 in the next 30 days alone.
Do zero-rated sales count towards the threshold?
Yes. Zero-rated sales are taxable supplies charged at 0%, so they count towards the £90,000. Exempt sales do not count — zero-rated and exempt are not the same thing.
If I sell only to consumers, should I register early?
Usually not, unless you have large VAT-bearing costs to reclaim. For consumer-facing businesses, adding 20% to prices can lose sales, and the admin cost is real. Wait until you must register, or until the reclaim clearly outweighs the price effect.
How long does VAT registration take?
HMRC usually sends your VAT number within a few weeks of a complete online application, but do not wait for the number to start planning: you must charge VAT from your effective registration date, and you can issue invoices showing VAT once you know that date.
Conclusion
So, do you need to register for VAT? The answer is a number, not a feeling: add up your last 12 months of taxable sales, look 30 days ahead, and compare both with £90,000. Over the line on either test, and registration is compulsory — register within 30 days and charge VAT from your effective date. Under the line, register early only if your customers can reclaim the VAT and your own input VAT makes it worthwhile. Either way, check monthly: the businesses that check monthly never get the nasty surprise.
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