VAT registration in the UK: when you must register and what happens next

By Accounting Solution · June 2026 · 7 min read

VAT is one of the most misunderstood taxes for growing small businesses. Many business owners either miss the point at which they should have registered, or voluntarily register too early without understanding the implications. This guide covers the essentials.

The VAT registration threshold

You are legally required to register for VAT if your taxable turnover exceeds £90,000 in any rolling 12-month period. This is not a calendar year threshold — it applies to any consecutive 12 months. If your turnover crosses £90,000 in, say, the 12 months to October 2026, you must register regardless of when your financial year ends.

You must also register if you expect your turnover to exceed £90,000 in the next 30 days alone. This catches businesses taking on large contracts or new clients.

What counts as taxable turnover?

Taxable turnover includes all sales of goods and services that are subject to VAT at any rate — standard rate (20%), reduced rate (5%), or zero rate (0%). It does not include exempt supplies (certain financial services, insurance, healthcare, and education). If your business has a mix of taxable and exempt income, the calculation becomes more nuanced.

Voluntary registration

You can register for VAT voluntarily even if your turnover is below the threshold. This makes sense if most of your customers are VAT-registered businesses — they can reclaim the VAT you charge, so it does not cost them more. You can then reclaim VAT on your business purchases, which can be significant if you have high input costs.

Voluntary registration is less attractive if your customers are mostly consumers or small businesses that cannot reclaim VAT, as charging VAT effectively makes you 20% more expensive.

What happens when you register?

Once registered, you must charge VAT on all your taxable supplies and issue VAT invoices. You submit VAT returns to HMRC — usually quarterly — showing the VAT you have collected and the VAT you have paid on purchases. The difference is either paid to HMRC (if you collected more than you paid) or reclaimed from HMRC (if you paid more than you collected).

Your VAT returns must be submitted digitally under Making Tax Digital for VAT, which has been mandatory for all VAT-registered businesses since April 2022.

VAT schemes worth knowing about

The Flat Rate Scheme lets smaller businesses pay a fixed percentage of their gross turnover to HMRC instead of calculating actual VAT on each transaction. It simplifies administration and can occasionally produce a saving, though for most businesses the standard method is more beneficial.

The Cash Accounting Scheme means you account for VAT when you are actually paid, rather than when you invoice. This helps cash flow if your customers are slow to pay.

The Annual Accounting Scheme allows you to file one VAT return per year with advance payments, reducing the quarterly filing burden.

Common VAT mistakes

• Missing the registration deadline — penalties apply from the date you should have registered
• Incorrectly treating zero-rated sales as exempt (they are different — zero-rated turnover still counts toward the threshold)
• Failing to register when taking over a VAT-registered business
• Not keeping adequate VAT records or issuing non-compliant invoices