The VAT Registration Threshold: When You Must Register, and When You Can Come Off

You must register for VAT once your taxable turnover for the last 12 months goes over £90,000, or as soon as you expect it to go over £90,000 in the next 30 days on its own. Both tests are live all year. Neither of them cares about your accounting year end or the 6 April tax year.

That is the whole problem. Most sole traders and small companies check their turnover once, when the accounts are done. The legal test runs on a rolling 12-month window that resets at the end of every single month. Cross it in July and only notice in the following March, and HMRC's position is blunt: if you register late you must pay VAT on any sales you have made since the date you should have registered. You pay that out of your own margin, on invoices where you never charged a penny of VAT.

The rolling 12-month test, and why checking at your year end fails

The backward-looking test asks a question at the end of every month: over the 12 months just ended, did taxable turnover exceed £90,000? Not the 12 months to your year end. The 12 months to the end of last month, and the 12 months to the end of the month before that, and so on forever.

Take Marcus, a mobile welder trading as a sole trader with an accounting year ending 5 April. His accounts to 5 April 2026 showed £84,100 of sales. Under £90,000, so he ticked it off and stopped thinking about VAT. Then a run of good months landed. Here is what the rolling window was actually doing:

The rolling total moves by the difference between this month and the month that just dropped out of the window. Marcus was not having a spectacular year. He was having an ordinary year that replaced a weak one. He crossed on 31 July 2026.

From there the clock is fixed. You have to register within 30 days of the end of the month in which you went over, so Marcus's deadline was 30 August 2026. His effective date of registration is the first day of the second month after he went over, which is 1 September 2026. From that date he is a VAT-registered business whether or not he has a VAT number, and every standard-rated sale he makes carries VAT.

The forward look: one contract can register you tomorrow

The second test has nothing to do with history. If at any point you expect your taxable turnover to go over £90,000 in the next 30 days by itself, you must register, and the deadlines are different and tighter.

Priya caters weddings and events. Her rolling 12-month turnover sits at £58,000, comfortably clear of the threshold. On 3 June she signs a festival contract worth £96,000, with everything supplied over the following four weeks. That single expectation trips the forward look on the day she signs.

She must register by the end of that 30-day period, so by 2 July. Her effective date of registration is 3 June, the date she realised, not the date the turnover actually arrived or the date she applied. The festival contract therefore sits inside her VAT registration from day one.

If she quoted a flat £96,000 with no mention of VAT and the customer refuses to pay more, and that price is treated as VAT-inclusive, the VAT buried in it is £96,000 ÷ 6 = £16,000. Had she spotted it on 3 June and quoted £96,000 plus VAT, the invoice would have been £115,200, the festival company would have reclaimed the £19,200 on its own return, and Priya would have kept the full £96,000. The whole £16,000 difference is a contract-drafting decision made in a single afternoon. Our VAT calculator will strip or add the VAT on any figure if you want to check what a quote is really worth.

What actually counts as taxable turnover

Taxable turnover is not profit, and it is not the number at the bottom of your bank statement. GOV.UK defines it as the total value of everything you sell that is not VAT exempt or out of scope. That means it includes:

• standard-rated sales at 20%
• reduced-rated sales at 5%
• zero-rated sales at 0%, which is the one people get wrong
• goods you hired or loaned to customers
• business goods you used for personal reasons
• anything you bartered, part-exchanged or gave away
• services you received from abroad that fall under the reverse charge
• building work over £100,000 that your business did for itself

Zero-rated is the trap inside the trap. A baker selling cold takeaway food, a children's clothing shop, a printer producing books: those sales are taxable at 0%, so they count in full towards the £90,000 even though no VAT is ever charged on them. Businesses that are wholly or mainly zero-rated can ask HMRC for permission not to register, but you have to ask. Nobody grants it automatically.

What is left out is genuinely exempt or out-of-scope income: insurance, most financial services, postage stamps, certain property transactions, and things like grants that are not consideration for a supply. If a chunk of your income is exempt rather than zero-rated, your VAT position gets more complicated rather than simpler, and it is worth taking advice before you assume you are safe.

Two more situations carry no threshold at all. If your business is based outside the UK and you supply any goods or services to the UK, you must register regardless of turnover. And in Northern Ireland, buying goods worth more than £90,000 in any 12-month period from EU VAT-registered suppliers triggers registration for those acquisitions.

What late registration really costs

Back to Marcus. His effective date was 1 September 2026, but nobody spots it until his accountant prepares the year to 5 April 2027, in the following winter. By the time he registers he has invoiced £118,000 since 1 September with no VAT on any of it. His customers are mostly private householders and small builders, so raising VAT-only invoices after the event is a conversation that mostly ends in silence.

The exposure on those sales is:

• If the amounts he charged are treated as VAT-inclusive: £118,000 ÷ 6 = £19,667
• If VAT is due on top of what he charged: £118,000 × 20% = £23,600

Against that he can reclaim input VAT on the materials and costs he bought in the same period. Say that comes to £4,100. His net cash cost is somewhere between roughly £15,600 and £19,500, on work he has already been paid for and already spent the money from. Then there is a failure to notify penalty on top, charged as a percentage of the VAT that was due late:

Read the top-left cell carefully, because it is the single most valuable line in this article. A non-deliberate failure that you disclose yourself, unprompted, within 12 months of the tax being due, can carry a penalty of 0%. The moment HMRC contacts you first, the floor rises to 10%, and once you are more than 12 months late the unprompted floor rises too. The full ranges are set out in HMRC's failure to notify factsheet. If you think you have already crossed the threshold, the correct move is to phone your accountant today rather than wait for a letter.

If your business runs alongside employment or other self-employed income, it is worth reading our beginner's guide to self-employed tax too, because VAT registration usually arrives at the same time as a jump in your self assessment obligations.

Exception from registration: the escape hatch people miss

Going over the threshold once, because of a one-off contract or a freak month, does not have to mean permanent VAT registration. HMRC operates an exception from registration. You can apply if both of the following are true: your taxable supplies went over the registration threshold in the last 12 months, and you can show HMRC that your taxable supplies will not go over the deregistration threshold of £88,000 in the next 12 months.

Note the asymmetry. You cross at £90,000, but to be excepted you have to demonstrate you will stay under £88,000 going forward. It is a forecast, and HMRC wants evidence: the lost contract, the closed site, the retiring partner, the order book. Vague optimism will not carry it.

The application is made through the VAT registration service, and it has to be made rather than assumed. If you cross the threshold, do nothing and later argue you were always going to fall back, you are a late registration, not an exception. Apply within the same 30-day window you would have used to register.

Deregistration: the £88,000 threshold and the £1,000 stock charge

There are two different reasons to come off the register, and only one of them is optional.

You must cancel if you stop being eligible to be registered, for example because you stop trading or stop making taxable supplies, and you must do it within 30 days or you may be charged a penalty. You may ask HMRC to cancel if your taxable turnover falls below £88,000. HMRC normally confirms a cancellation within 40 working days, though it can take longer.

Now the bit that surprises people. On your cancellation date you have to account for VAT on the stock and other assets you still hold, if you reclaimed or could have reclaimed VAT when you bought them and the total VAT due on those assets is over £1,000. Under £1,000 and there is nothing to pay. Over it, and the whole amount goes on your final return.

Rosa runs a picture-framing shop and has been registered since 2019. She drops her trade wholesale line and her rolling turnover falls to £71,000, with £74,000 forecast for the next 12 months. That is under £88,000, so she can apply to deregister. On her cancellation date she still holds framing stock and a van she reclaimed VAT on, and the VAT due on their value is £1,450. Because that is over £1,000, she pays the full £1,450 on her final return.

Is it worth it? Her customers are consumers who cannot reclaim VAT. If she keeps her prices exactly where they are, the VAT she stops handing over on £74,000 of sales is £74,000 ÷ 6 = £12,333 a year. Against that she loses input VAT recovery on her costs, worth about £2,900 a year, and pays the one-off £1,450. First-year gain of roughly £7,983, then about £9,433 a year after that. For a business selling to VAT-registered customers the sums usually point the other way, because those customers reclaim the VAT and only your input tax recovery is real money. You must also keep all your VAT records for six years after deregistering.

Voluntary registration: when going in early is the right call

You can register voluntarily below £90,000, and for some businesses it is straightforwardly profitable. It works when your customers are VAT-registered businesses who reclaim whatever you charge them, and when you carry real input VAT on stock, equipment, vehicles, subcontractors or premises. In that setup registration turns your input VAT from a cost into a refund and costs your customers nothing.

It works badly when you sell to consumers. Adding 20% to your price makes you more expensive than the unregistered competitor down the road, and absorbing it cuts your margin by a sixth.

You can also backdate a voluntary registration by up to four years from the date the business registers, which is worth considering if you have been buying heavily. Choose the date carefully, because you cannot change your VAT start date once you are registered.

If your turnover is under £150,000 excluding VAT, you may be able to join the Flat Rate Scheme, which replaces the normal input and output tax calculation with a single percentage of gross turnover. Run your own numbers through the flat rate VAT calculator before you commit, because it favours low-cost service businesses and penalises anyone buying a lot of goods. For businesses looking at their overall structure at the same time, our comparison of PAYE versus self-employment covers the other half of the decision.

A monthly routine that stops this happening

This is a bookkeeping problem dressed up as a tax problem, and the fix takes about two minutes a month.

• On the last day of every month, total your taxable sales for the 12 months just ended. Include zero-rated and reduced-rated sales.
• Set an alert at £75,000, not £90,000. That gives you time to reprice, restructure or plan rather than react.
• Every time you quote a contract worth more than about £40,000, ask whether it alone could push you over £90,000 within 30 days. If it could, quote plus VAT and say so in writing.
• Once registered, remember that all VAT-registered businesses should now be signed up for Making Tax Digital for VAT, which means digital records and compatible software rather than a spreadsheet emailed to your accountant.

Once you are over the line, the mechanics take over: charge the right rate, issue proper VAT invoices, and file on time. An invoice generator that produces compliant VAT invoices with your registration number on them removes one of the more common sources of correction later. The rate itself is 20% standard, 5% reduced and 0% zero-rated, and the reduced rate covers more than people expect, as the cut to 5% on children's meals showed. If digital filing is new to you, our guide to Making Tax Digital covers the direction of travel across HMRC's systems.

The threshold figures and deadlines in this guide come from GOV.UK's VAT registration guidance. Check them before you act, because thresholds do move, and check your own rolling total before you assume this page is not about you.