Do You Need to Register for VAT? The £90,000 Test, the 30-Day Rule and How to Track It

HMRC counted 2,330,400 VAT-registered traders in 2024/25, and 683,700 of them, 29%, had turnover below the registration threshold, so they registered by choice. On the other side of the line sits a group the Office for Budget Responsibility has been watching: businesses that deliberately stop growing just under the threshold. The OBR expected the number capping their turnover to nearly double from 23,000 to 44,000 between 2017/18 and 2025/26, with the lost turnover rising from £110 million to £350 million a year. A cafe that closes on Mondays in March, a plumber who stops answering the phone in February: that is the VAT threshold at work.

Whether you need to register for VAT is a question with an exact answer, and most owners get it wrong in one of two ways: they register late because nobody was counting, or they stay small for years because they never did the maths on registering by choice. This guide gives the two tests, what counts as turnover, the penalties for missing the date, the honest case for and against voluntary registration, the Flat Rate Scheme rates, the Making Tax Digital rules, and four prompts that get an AI agent to count the rolling total from your invoices every week and tell you the month before it matters. The rules are from GOV.UK and HMRC's manuals, checked on 21 October 2026.

The two tests

The threshold has been £90,000 since 1 April 2024, with deregistration at £88,000, and the Budget of 26 November 2025 left both unchanged. The 12-month period is not your financial year or the calendar year: it is any 12 months ending on the last day of any month, which is why a spreadsheet updated at year end misses it and a weekly count does not.

What counts as taxable turnover

Everything you sell that is not exempt or outside the scope of VAT: standard-rated sales at 20%, reduced-rated sales at 5%, and zero-rated sales at 0%. A bakery's zero-rated bread counts towards the £90,000 even though no VAT is charged on it. Exempt sales do not count: insurance, most financial services, health services from registered practitioners, and education from an eligible body (private school fees have been standard-rated since 1 January 2025). Hospitality, hot takeaway food and home delivery are standard-rated. The agent in prompt 1 sorts your sales into the four categories before it counts.

Build the tracker in four prompts

1. The rolling total

2. The decision: register by choice or stay below

3. The quarterly return pack

4. The price change for consumer customers

Four prompts, an afternoon the first time, and then the rolling total arrives every Monday. The free plan does it on 100 credits a day; the Go plan at £7 a month adds 2,000 credits for the quarterly packs.

What registering late costs

You are registered from the date you should have been, and HMRC expects the VAT from that date even if you never charged it, which for a business selling to consumers means paying 20% out of your own margin on every sale since the month you crossed. On top sits the failure-to-notify penalty under HMRC's Compliance Handbook: up to 30% of the VAT due for a non-deliberate failure, 70% if it was deliberate and 100% if deliberate and concealed, reduced for telling HMRC yourself. If you come forward unprompted within 12 months and the failure was not deliberate, the minimum penalty is nil; after 12 months it is 10%, and 20% if HMRC found you first. The weekly count in prompt 1 is cheaper than any of those numbers.

Should you register before you have to?

• For it. You reclaim VAT on your costs from the day you register, on goods bought up to four years earlier that you still hold, and on services bought up to six months earlier. Business customers who are VAT-registered do not care about the 20% because they reclaim it, and some will not deal with an unregistered supplier. A VAT number on the invoice reads as an established business.
• Against it. If your customers are consumers, the 20% comes out of their pocket or your margin. The IMF working paper on UK VAT by Liu, Lockwood, Almunia and Tam found that the more a business sells to consumers, the more likely it is to bunch below the threshold rather than register. Prompt 2 runs the actual numbers for your mix.
• The scheme that changes the answer. On the Flat Rate Scheme you charge customers 20% but pay HMRC a fixed percentage of your gross turnover and keep the difference, with no input VAT to track. It is open to businesses with taxable turnover of £150,000 or less, excluding VAT, and you leave when income passes £230,000.

Flat Rate Scheme rates for common trades

The limited cost rule catches most service businesses that buy few goods, and at 16.5% of gross turnover the scheme can cost more than standard accounting. Prompt 2 compares both before you choose.

Making Tax Digital and the return

Every VAT-registered business has had to keep digital records and file through compatible software since April 2022; HMRC's software finder lists hundreds of products with a filter for free versions. The return and the payment are due one calendar month and seven days after the end of the quarter. Late returns earn a penalty point each, and at four points for a quarterly filer the penalty is £200, with another £200 for each late return after that. Late payment is free for the first 15 days, then 3% of the VAT outstanding at day 15, a further 3% of what is still outstanding at day 30, and a daily charge at 10% a year from day 31. The quarterly pack in prompt 3 is built around the deadline, not the quarter end.

How an AI agent differs from an accounting app

ChatGPT, Claude, Gemini, Microsoft Copilot, Manus and Meta's Muse will all explain the threshold. Jobbit counts it:

• It reads the invoices and the bank export and sorts every sale by VAT category.
• It keeps the rolling 12-month total every week and warns at £80,000, months before the deadline.
• It runs the register-or-stay model on your real customer mix and margin.
• It compares standard accounting with the Flat Rate Scheme including the limited cost trap.
• It prepares the quarterly pack with the deadline, the nine boxes and the missing receipts.
• It rewrites the price list and the invoice template on the day you register.

A one-afternoon plan

• 1 pm. Export 12 months of sales invoices or the bank statement. Run prompt 1. Note the rolling total and the month.
• 2 pm. Write down your customer mix, your margin and your monthly VAT-able costs. Run prompt 2.
• 3 pm. If the answer is register: apply on GOV.UK, choose your software from HMRC's list, and run prompt 4 for the price list. If the answer is wait: ask the agent to send the rolling total every Monday.
• 4 pm. Put the first return deadline in the diary and ask the agent for the quarterly pack a week before it.

Read next

• Do you need invoicing software?: the invoice that carries the VAT number.
• How to write a receipt in the UK: what a VAT receipt must show.
• AI for spreadsheets: if your ledger lives in Excel.

Frequently asked questions

What is the VAT registration threshold in 2026?

£90,000 of VAT-taxable turnover in any rolling 12-month period, in force since 1 April 2024 and unchanged by the November 2025 Budget. Deregistration is at £88,000. You must also register if you expect your taxable turnover in the next 30 days alone to exceed £90,000.

When do I have to register for VAT after going over the threshold?

Within 30 days of the end of the month in which your rolling 12-month turnover went over £90,000, and your registration takes effect from the first day of the second month after that. Under the 30-day forward test you register by the end of the 30 days and are registered from the date you realised. An agent on Jobbit counts the rolling total weekly so the date is never a surprise.

Does zero-rated income count towards the VAT threshold?

Yes. Taxable turnover includes standard-rated, reduced-rated and zero-rated sales. Only exempt sales, such as insurance, most financial services and registered health services, and sales outside the scope of UK VAT are left out.

What happens if I register for VAT late?

HMRC registers you from the date you should have been registered and expects the VAT from then, whether or not you charged it. A failure-to-notify penalty of up to 30% of that VAT applies for a non-deliberate failure, rising to 70% or 100% for deliberate cases, reduced to nil for a non-deliberate failure you report yourself within 12 months.

Is it worth registering for VAT voluntarily?

Often yes if your customers are VAT-registered businesses, because they reclaim the VAT and you reclaim yours on costs, including goods bought up to four years earlier that you still hold. Often no if your customers are consumers, because the 20% comes from their pocket or your margin. Prompt 2 models both on your real numbers, including the Flat Rate Scheme.

What is the Flat Rate Scheme and who can use it?

A scheme where you charge customers VAT at 20% but pay HMRC a fixed percentage of your gross turnover and keep the difference, with no input VAT to track. It is open to businesses with taxable turnover of £150,000 or less excluding VAT, you leave at £230,000, there is a 1% discount in the first year, and a limited cost business that buys few goods pays 16.5%, which often makes it worse than standard accounting.

Can an AI agent track my VAT threshold?

Yes. Give an agent on Jobbit your invoices or bank export and it sorts sales by VAT category, keeps the rolling 12-month total every week, warns you at £80,000, models whether to register by choice, prepares the quarterly return pack for your Making Tax Digital software and rewrites your price list and invoice template when you register.