When Do You Need to Register for VAT in the UK?

You just hit send on an invoice - the kind that finally makes a good year look like a great one, and out of curiosity you open the spreadsheet where you track total sales. Add that invoice to what's come in over the last twelve months…

you're sitting at £91,400.

VAT registration threshold is £90,000.

So congratulations in a very specific, paperwork-flavoured sort of way. You've crossed it.

In short, knowing when to register for VAT in the UK comes down to two things - your trailing twelve months crosses £90,000, or you already know it's about to.

Taxable turnover counts: standard-rated, reduced-rated, and zero-rated sales all go toward the £90,000, even the zero-rated ones that add no VAT to an invoice.

VAT exempt income, like some financial services or education, doesn't count at all.

Once your total for the trailing twelve months clears £90,000, you have 30 days from the end of the month you crossed the line to notify HMRC. Your registration becomes effective from the first day of the second month after that.

If you cross the line partway through August, you'd need to register by the end of September, with VAT applying to your sales from 1 October.

There's also a possible situation that skips the twelve-month maths altogether. If you land a large contract and can see your turnover clearing £90,000 within the next 30 days alone, you have to register based on that realisation, no waiting for the running total to agree with you.

Your effective date is the day you knew, even though you still have 30 days to file.

Registering changes quite a lot of your everyday admin. VAT for limited company owners means tighter bookkeeping and it's much the same for LLP and LP owners.

From your effective date, you're charging VAT on sales and reclaiming it on eligible purchases, which means every receipt and every card transaction needs sorting correctly before your first return is due.

If your team buys things across several cards, giving each person their own card with a set limit keeps that sorting manageable well before it turns into a shoebox of receipts situation. Ampere's team cards let you issue individual cards to whoever handles purchasing, cap what each one can spend, track spend as it happens, and pause any card if something looks off.

You don't have to wait.

Plenty of businesses register voluntarily well before their turnover gets anywhere near £90,000, usually because they're already paying VAT on stock or services and want it back, or because their clients are VAT-registered themselves and barely blink at an extra 20% on an invoice.

Sometimes it's also simply about looking established, since a VAT number on your invoices reads like a business that's been around a while.

Missing that window is expensive, as HMRC doesn't cut much slack for late registration, and ‘I didn't check’ won't count as an excuse.

You'll owe VAT on every sale made from the date you should have registered, and a penalty can follow on top depending on how much is owed and how late the registration is. Better to check your rolling total every month, because it's easy to miss the moment you cross £90,000 in the middle of a busy quarter.

If your turnover later drops, there is still a way back. Once you expect your taxable turnover to stay below £88,000 over the next 12 months you can ask HMRC to cancel your registration, though six years of VAT records still need keeping after that.