Most new founders have the same VAT question, and they usually ask it too late: at what point does a startup actually have to register? The answer is simpler than most people expect, but the timing rules catch plenty of growing businesses out.
The short answer: a startup must register for VAT once its taxable turnover goes over £90,000 in any rolling 12-month period, or if it expects to pass £90,000 in the next 30 days alone. Below that line, registration is voluntary — a choice with real pros and cons, not a legal duty. This guide explains the threshold, the deadlines, and what changes once you are registered, so your startup never gets a surprise bill from HMRC.
The £90,000 threshold — and what counts towards it
The VAT registration threshold for 2026/27 is £90,000 of taxable turnover. That figure has been unchanged since 1 April 2024, when it rose from £85,000. The key word is turnover, not profit. HMRC looks at what you sell, not what you keep after costs.
What counts is any sale that is not exempt or out of scope. Standard-rated sales at 20%, reduced-rated sales at 5% and zero-rated sales at 0% all count towards the £90,000. Exempt sales — such as most insurance and financial services, and residential rents — do not count.
| Counts towards the £90,000 | Does not count |
|---|---|
| Standard-rated sales (20%) | Exempt sales, such as most insurance and financial services |
| Reduced-rated sales (5%) | Residential rents and other exempt supplies |
| Zero-rated sales (0%), such as most food and children’s clothes | Sales that are out of scope of UK VAT |
| Sales to businesses and to consumers, UK-wide | Money that is not a sale, such as a loan or a grant |
That zero-rated point surprises founders. A food startup selling zero-rated products can still cross the threshold and must register, even though it charges its customers 0% VAT. The threshold test is about the size of your sales, not the rate you charge.
The two tests that trigger registration
There are two tests, and either one can make registration compulsory.
The backward look. At the end of every month, add up your taxable turnover for the previous 12 months. This is a rolling period, not the tax year and not your accounting year, so the total is re-checked every single month. If it goes over £90,000, you must register within 30 days of the end of that month. Your effective date of registration is the first day of the second month after you crossed the threshold.
The forward look. If at any moment you expect your taxable turnover to exceed £90,000 in the next 30 days alone — for example, because you have just signed one very large contract — you must register by the end of that 30-day period, and registration takes effect from the date you realised, not from when the money arrives.
A worked £ example: Aisha’s branding studio
Aisha runs a small branding studio from home in Manchester. Her monthly sales grow steadily through her first two years. At the end of September, she adds up the previous 12 months and finds taxable turnover of £92,500 — over the line for the first time.
Under the backward-look rule, she must register within 30 days of the end of September, so by 30 October, and her effective date of registration is 1 November. From 1 November she must charge VAT on her sales, even if a client project was agreed earlier at a price with no VAT mentioned.
That last point is where startups lose money. Suppose Aisha invoices a client £1,200 in November and forgets to add VAT. HMRC still treats that £1,200 as VAT-inclusive, so £200 of it (one-sixth, at the standard 20% rate) belongs to HMRC, not to her. Registering on time and repricing quotes from the effective date avoids that trap entirely.
Should your startup register voluntarily?
Below £90,000, vat registration is a business decision. There are genuine reasons to do it early, and genuine reasons to wait.
| Registering early can help when… | Waiting can be smarter when… |
|---|---|
| You buy a lot of VAT-charged stock or equipment and want to reclaim the input VAT | Most of your customers are ordinary consumers who cannot reclaim VAT, so adding 20% makes you look expensive |
| Your customers are mostly VAT-registered businesses, who can reclaim the VAT you charge | Your sales are well below £90,000 and your bookkeeping time is already stretched |
| Being VAT-registered makes your startup look established to larger clients | Your margins are thin and absorbing or passing on VAT would wipe them out |
Work it out with real numbers before deciding. If you spend £2,000 a month on VAT-charged supplies, reclaiming the VAT is worth about £333 a month at the standard rate — real money for a young business. But if your customers are consumers and your competitors are not VAT-registered, a 20% price rise can cost you sales. There is no universally right answer; there is only the answer that fits your customers and your costs.
What changes once you are registered
Registration brings a new monthly and quarterly routine. You charge VAT on your taxable sales, you reclaim VAT on eligible business purchases, and you file a VAT return — normally every quarter — paying HMRC the difference. You also join Making Tax Digital for VAT, which means keeping digital records and filing through compatible software, unless you are exempt.
Your invoices change too. A VAT invoice must show your VAT number, the VAT rate applied, and the VAT amount, among other details. And your prices need a decision: do you add VAT on top of your current price, or treat your current price as VAT-inclusive and absorb the difference? Decide before your effective date, tell your customers, and update your quotes and website pricing at the same time.
One simpler option worth knowing about is the Flat Rate Scheme. If you expect taxable turnover of £150,000 or less (excluding VAT) in the next 12 months, you can pay HMRC a fixed percentage of your VAT-inclusive turnover instead of tracking VAT on every purchase, and you get a 1% discount in your first year of VAT registration. Watch out for the limited cost business rule, though: if you spend very little on goods, you must use a 16.5% rate, which usually makes the scheme more expensive than standard accounting. Check your sector rate on GOV.UK before applying.
5 startup VAT mistakes to avoid
- Counting profit, not turnover. The threshold is about sales. A startup can cross £90,000 while barely breaking even, and registration is still compulsory.
- Checking once a year. The test is monthly and rolling. A busy December can push a quiet business over the line in a month you were not watching.
- Forgetting zero-rated sales. They count towards the threshold even though you charge 0% VAT on them.
- Charging VAT before you are registered. Only registered businesses can charge VAT. If you add it early, you create a mess with customers and HMRC.
- Missing the 30-day deadline. Late registration does not move your start date. HMRC registers you from the date you should have registered, and you owe VAT on sales from then, whether or not you charged it — plus a possible penalty depending on how much is owed and how late you are.
Frequently asked questions
Do startups need to register for VAT from day one?
No. There is no requirement to register when you start trading. You register when your taxable turnover crosses £90,000 in a rolling 12 months, when you expect to cross it in the next 30 days, or voluntarily if it suits your business.
What is the VAT registration threshold for startups in 2026/27?
£90,000 of taxable turnover in any rolling 12-month period. The deregistration threshold is £88,000 — if your turnover falls below that, you can ask to deregister.
Can a startup register for VAT voluntarily?
Yes. You can choose to register below the threshold. The main benefits are reclaiming VAT on your business costs and looking established to business customers; the main costs are extra admin and a 20% price rise for customers who cannot reclaim VAT.
What happens if a startup registers for VAT late?
HMRC backdates your registration to the date you should have registered. You must pay VAT on sales from that date, even if you did not charge it, and you may face a penalty. Registering within the 30-day window avoids this entirely.
Conclusion
VAT registration is not something to fear, but it is something to track. Keep a simple monthly running total of your taxable turnover, diarise the 30-day deadline the moment you cross £90,000, and decide early whether voluntary registration helps or hurts your prices. For the official steps and current thresholds, follow GOV.UK’s register for VAT guide — before you apply — and if your numbers are close to the line, a quick word with an accountant is money well spent.
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