Knowing when to register for VAT matters because the deadline is based on taxable turnover, not profit or the date of your year-end. A growing business can cross the threshold between accounts, so VAT should be monitored every month.
The compulsory VAT registration threshold is currently £90,000. However, there are two different tests, and each has its own deadline and effective date. Registering late can leave a business paying VAT from its own margin even if it did not charge customers at the time.
When must a business register for VAT?
HMRC says a business must register if either of the following applies:
- its total VAT-taxable turnover for the last 12 months goes above £90,000; or
- it expects its VAT-taxable turnover to go above £90,000 in the next 30 days.
These tests work differently. Therefore, it is important to apply the correct one rather than waiting for annual accounts or a tax return.
The rolling 12-month test
At the end of every month, calculate taxable turnover for the previous 12 months. This is a rolling period, not a calendar year, tax year or financial year.
If the total first exceeds £90,000 during a month, you normally have 30 days from the end of that month to register. Your effective date of registration is usually the first day of the second month after you crossed the threshold.
For example, if taxable turnover first exceeds the threshold on 15 July, the normal registration deadline is 30 August and the effective date is 1 September.
The next 30 days test
A separate rule applies if you expect taxable turnover to exceed £90,000 within the next 30 days alone. This can happen after winning a large contract or receiving an unusually large order.
In this situation, you must apply by the end of that 30-day period. Crucially, the effective date is the date you first realised the threshold would be exceeded, not the later date on which the sales took place.
HMRC’s official guidance on when to register for VAT provides examples of both tests.
What counts as VAT-taxable turnover?
VAT-taxable turnover is the total value of the goods and services a business supplies that are not exempt from VAT. It generally includes standard-rated, reduced-rated and zero-rated sales. Zero-rated is not the same as exempt.
Exempt supplies are normally left out of the threshold calculation. However, mixed businesses, overseas sales, grants, asset disposals and transactions involving Northern Ireland can require closer analysis. If the VAT treatment of a sale is unclear, check it before relying on a turnover figure.
Should you register voluntarily below £90,000?
A business can choose voluntary VAT registration before reaching the threshold. This can be useful, but it is a commercial decision as well as a tax decision.
Possible advantages
- You may be able to reclaim eligible VAT on business purchases.
- VAT registration may be expected by larger customers or suppliers.
- Registering early can prevent a rushed change when turnover approaches the threshold.
- It may support a growing business with substantial VAT-bearing costs.
Possible disadvantages
- You must charge the correct VAT on taxable sales from the effective date.
- Prices may become less competitive when customers cannot reclaim VAT.
- Returns, digital records and payment deadlines create ongoing administration.
- VAT collected from customers must be managed carefully so it is available for HMRC.
For a mainly business-to-business company, customers may be able to reclaim the VAT charged. By contrast, a consumer-facing business may need to increase its final price or absorb some VAT within its existing price. Model both outcomes before registering voluntarily.
What changes after VAT registration?
From the effective date, a business must account for VAT correctly on taxable sales. It should issue valid VAT invoices, apply the right rate and keep evidence for any VAT it reclaims.
Most businesses submit VAT returns quarterly, although other accounting arrangements may be available. A standard quarterly return and payment are usually due one calendar month and seven days after the end of the VAT period. Always confirm the exact deadline in the business’s VAT online account.
VAT-registered businesses must normally follow Making Tax Digital for VAT. This means keeping specified records digitally and submitting returns using compatible software, unless HMRC has granted an exemption. HMRC’s VAT record-keeping guidance explains which records must be retained and how digital links work.
Common VAT registration mistakes
- Checking turnover only once a year instead of using a rolling 12-month calculation.
- Using profit rather than taxable sales to test the threshold.
- Leaving zero-rated sales out of taxable turnover.
- Waiting until an invoice is paid when the VAT tax point may be earlier.
- Charging VAT before a VAT number and effective date have been confirmed.
- Failing to update prices, contracts, invoices and accounting software.
- Spending VAT collected from customers instead of reserving it for the payment deadline.
A practical VAT registration checklist
- Calculate VAT-taxable turnover for the latest rolling 12 months.
- Review signed contracts and expected sales for the next 30 days.
- Confirm whether any supplies are exempt, zero-rated or outside the scope of UK VAT.
- Model how VAT registration will affect prices, margins and customers.
- Choose compatible bookkeeping and VAT-return software.
- Plan invoice changes and customer communications.
- Set aside VAT collected and record filing deadlines.
- Seek advice early if a threshold was crossed in a previous period.
London Accountants can review your taxable turnover, explain the timing rules and manage registration, digital records and VAT returns. Explore our bookkeeping and VAT service or contact the team before the threshold becomes an urgent deadline.
