When Do I Have to Register for VAT as a Small Trade Business?

Turnover creeping past a comfortable figure most months is a good problem to have — until it means you’re legally required to register for VAT, whether or not you feel ready. There’s no discretion once you cross the line, and the test that decides it isn’t your accounting year. Here’s what gov.uk itself says about when registration becomes compulsory, what happens if you miss the deadline, and whether registering before you’re forced to is worth considering.

The £90,000 threshold, and what it measures

You must register for VAT once your VAT taxable turnover goes over £90,000 [1]. That’s the current compulsory registration threshold gov.uk publishes for the whole of the UK, and it isn’t a per-tax-year allowance you get to reset each April — it’s tested on a rolling basis, which is where most small trade businesses trip up.

The rolling 12-month test

The main trigger looks at the last 12 months on a rolling basis, not your tax year or accounting year: if your total taxable turnover for the previous 12 months goes over £90,000, you have to register within 30 days of the end of the month in which you crossed it [2]. Gov.uk’s own worked example: cross the threshold on 15 July, and you must register by 30 August, with an effective registration date of 1 September [2]. Because the window rolls forward every month, a single strong quarter — extra call-outs, a run of bathroom fits, a big commercial contract — can tip you over even if your turnover for the tax year as a whole looks unremarkable.

The 30-day forward-looking test

There’s a second, separate trigger that catches businesses the rolling test wouldn’t: if you expect your taxable turnover to go over £90,000 in the next 30 days alone, you must register straight away, not wait for the 12-month figure to catch up [2]. Gov.uk’s example here: you agree a £100,000 contract on 1 May, so you must register by 30 May, and your effective date of registration is backdated to 1 May — the day you realised, not the day the money actually came in [2]. For a trade business, signing one large job or a cluster of accepted quotes in the same month is enough to trigger this test on its own.

What happens if you miss the deadline

Registering late doesn’t excuse the VAT you should have charged: HMRC still expects you to account for VAT on everything you sold from the date you should have registered [2]. On top of that liability, a late registration penalty applies as a percentage of the VAT that was due: 5% if you register up to 9 months late, 10% if it’s between 9 and 18 months late, and 15% beyond that, subject to a minimum penalty of £50 [4]. The size of that percentage is set by how long the gap runs, so catching a crossed threshold early is the single biggest lever you have over the eventual bill.

Should you register before you’re forced to?

Gov.uk is explicit that you can choose to register even if your turnover is under £90,000 — this is voluntary registration [2]. Whether that’s worth doing before you’re forced into it depends on who you’re invoicing. If most of your customers are VAT-registered businesses, they can reclaim the VAT you charge, so adding it to your invoices costs them nothing, and you get to reclaim VAT yourself on tools, materials, and van costs. If most of your customers are homeowners, registering early means adding the standard rate of 20% [5] to every quote with no equivalent business able to reclaim it, which can make you look more expensive next to an unregistered competitor quoting the same job. There’s no single right answer here — it’s a trade-off between reclaiming input VAT and staying price-competitive on domestic work, and it’s worth weighing against your own customer mix before volunteering.

If your turnover falls back below the threshold

VAT registration isn’t necessarily permanent. If your taxable turnover later falls below £88,000, you can apply to cancel your registration, including online in most cases [3]. That’s a separate, lower figure from the £90,000 registration threshold, deliberately set below it so a business doesn’t bounce in and out of VAT registration every time turnover dips slightly [3].

What to do next

Loomwork Ai’s compliance audit checks your rolling 12-month turnover against the £90,000 registration test [1], so you’re not relying on a rough mental estimate of how close you are to the line.