Value Added Tax is one of the areas of UK tax that generates the most questions from growing businesses. The compulsory threshold is well-known — £90,000 of taxable turnover in any rolling 12-month period — but the decision of whether to register before you reach it is less straightforward, and the mechanics of how the threshold is measured catch a number of businesses out.
This post covers the key points: how mandatory registration works, when voluntary registration makes sense, how the flat rate scheme can simplify things, and what registration actually requires from you on an ongoing basis.
How the VAT threshold works
The compulsory registration threshold is currently £90,000 of VAT-taxable turnover, a figure that has been in place since April 2024 when it rose from £85,000. The deregistration threshold sits just below at £88,000.
Two important points that are often misunderstood:
First, the threshold is measured on a rolling 12-month basis, not on your financial year or tax year. HMRC looks back at the previous 12 months from the end of every calendar month. This means your registration obligation can be triggered at any point — not just at year-end. Many businesses only realise they have crossed the threshold when they look at their annual accounts, by which point they may already be in breach.
Second, there is a forward-looking test. If at any point you have reasonable grounds to believe your taxable turnover will exceed £90,000 in the next 30 days alone — for example, you have just signed a large contract — you must notify HMRC immediately. Registration takes effect from the start of that 30-day window, not from when you notify HMRC.
The practical implication: if your turnover is growing, monitor your rolling 12-month total monthly, not annually. Waiting until year-end accounts are prepared is how late registrations happen — and late registration means owing VAT on sales where you did not charge it, paid from your own margin.
What VAT registration involves
Once registered, you are required to:
- Charge VAT at the appropriate rate on all VAT-taxable sales — the standard rate is 20%, with a reduced rate of 5% and a zero rate for certain goods and services
- Submit VAT returns, usually quarterly, showing output VAT collected on sales and input VAT paid on purchases
- Pay any VAT owed to HMRC by the return deadline — one month and seven days after the end of each VAT period
- Keep digital records that meet Making Tax Digital requirements — VAT-registered businesses are already within scope of MTD for VAT
- Issue VAT invoices to VAT-registered customers that include your VAT registration number
In return, you can reclaim input VAT on goods and services you purchase for your business. For businesses with significant expenditure on VAT-bearing costs, this can produce meaningful savings.
Voluntary registration — when it makes sense
Any business below the £90,000 threshold can choose to register voluntarily. Whether this is the right move depends heavily on who you sell to and what your cost base looks like.
The case for registering early
- Your clients are VAT-registered businesses. If your customers can reclaim the VAT you charge, your prices do not effectively increase from their perspective. A £1,000 invoice becomes £1,200 including VAT — but the client reclaims the £200, leaving the net cost unchanged. In this situation, VAT registration costs you nothing in terms of competitiveness and you benefit from reclaiming input VAT on your own purchases.
- You have significant VAT-bearing costs. If you spend heavily on equipment, software, professional services, or materials that carry VAT, reclaiming that input VAT represents a real cash saving. The higher your cost base relative to turnover, the stronger the argument for voluntary registration.
- You want to reclaim VAT on pre-registration costs. HMRC allows you to reclaim VAT on goods purchased up to four years before registration (if still in use) and on services received within six months of registration. Registering voluntarily before a large purchase can unlock a retrospective benefit.
- Your turnover is approaching the threshold. Registering voluntarily gives you time to set up systems, adjust pricing, and inform clients before you are legally required to — rather than managing the transition under time pressure.
- Credibility with certain clients. Some larger organisations and public sector buyers expect their suppliers to be VAT-registered. A VAT number on an invoice signals a degree of business maturity.
The case against registering early
- Your customers are consumers or non-VAT-registered businesses. If you sell to individuals or small businesses that cannot reclaim VAT, adding 20% to your prices either reduces your competitiveness or compresses your margin if you absorb the cost. This is the most common reason voluntary registration does not make sense.
- Your costs are low. If you run a service-based business with minimal VAT-bearing expenditure, the input VAT you can reclaim may not justify the additional compliance burden.
- Admin overhead. VAT registration brings quarterly returns, digital record-keeping, and ongoing compliance. For a very small business, this is a meaningful addition to the administrative workload.
Standard rate vs. flat rate scheme
When you register for VAT, you can choose between the standard method and the Flat Rate Scheme (FRS). The FRS is available to businesses with VAT-inclusive turnover below £150,000 and is designed to simplify the process.
Under the standard method, you charge VAT on sales at 20%, reclaim VAT on purchases, and pay HMRC the difference each quarter. Under the flat rate scheme, you still charge customers 20% VAT but pay HMRC a fixed percentage of your gross (VAT-inclusive) turnover — the percentage varies by trade sector and is set by HMRC to reflect the average input VAT in that type of business.
| Sector example | Flat rate % |
|---|---|
| Accountancy or bookkeeping | 14.5% |
| IT consultancy or data processing | 14.5% |
| Management consultancy | 14% |
| Legal services | 14.5% |
| Advertising | 11% |
| Architect, civil and structural engineer | 14.5% |
In the first year of joining the FRS, a 1% discount applies — so an IT consultant paying 14.5% would use 13.5% in year one.
The FRS works in your favour if the flat rate percentage for your sector is lower than your actual VAT liability under the standard method — in other words, if you charge more VAT on sales than you spend on VAT-bearing purchases. For low-overhead service businesses, this can generate a small but consistent benefit. However, there is an important catch: if you spend less than 2% of your turnover on goods, HMRC classifies you as a limited cost business and requires you to use a flat rate of 16.5% — which typically makes the scheme financially neutral or slightly worse than the standard method.
FRS example: You invoice a client £1,000 plus VAT, collecting £1,200. Under the FRS at 14.5%, you pay HMRC £174 (£1,200 × 14.5%), keeping £26 as a benefit. Under the standard method, you would pay HMRC £200 output VAT minus whatever input VAT you can reclaim on your own purchases. If your purchases are low, the FRS saves you money. If your purchases are high, the standard method is likely better.
Key figures at a glance
| Item | Figure |
|---|---|
| Compulsory registration threshold | £90,000 (rolling 12 months) |
| Deregistration threshold | £88,000 |
| Standard VAT rate | 20% |
| Reduced VAT rate | 5% |
| FRS eligibility (turnover limit) | £150,000 (VAT-inclusive) |
| Limited cost business flat rate | 16.5% |
| FRS first-year discount | 1% reduction on your sector rate |
| Notification deadline after breach | 30 days from the end of the month you exceeded the threshold |
What to do next
If your turnover is comfortably below £90,000 and your customers are primarily consumers or non-VAT-registered businesses, there is likely no immediate need to register. If you are approaching the threshold, sell predominantly to VAT-registered clients, or have significant VAT-bearing costs, voluntary registration is worth modelling before your hand is forced.
The most important thing in either case is to know where you stand. Tracking your rolling 12-month turnover monthly takes minutes and removes the risk of an unexpected compulsory registration — which, if it happens late, means owing VAT on past sales you never collected.
Need help with VAT registration or returns?
We handle VAT registration, quarterly returns, and scheme advice for sole traders and limited companies across the UK.
Get in TouchThis article is for general information purposes and does not constitute tax advice. VAT rules and thresholds can change. Always verify current figures with HMRC or speak to a qualified accountant before making decisions about VAT registration.