When Must a UK Business Register for VAT?

The £90,000 Threshold: The Key Number You Must Know

As of 2026, if your business turnover exceeds £90,000 in any 12-month rolling period, you must register for VAT. This is the law. Miss the deadline and HMRC can fine you, demand back VAT, and demand interest on top.

What "Rolling 12 Months" Actually Means

It's not a calendar year. It's any consecutive 12-month period. So if you hit £90,001 on 1 May 2026, you must register immediately — not wait until December 31st.

HMRC calculates your rolling 12-month turnover daily. The moment you cross £90,000, you're legally obliged to register within 30 days. If you don't, they can penalise you.

What Counts Towards the Threshold?

Include in your turnover calculation:

• All invoiced sales — Every pound you've charged clients
• Goods supplied to clients — Even if partly paid or unpaid
• Free samples or promotional items (if given to customers)
• Services you provide — Whether paid in full, partial payment, or on credit

Do NOT include:

• Sales of capital assets (selling office equipment, vehicles)
• Grants or subsidies
• Loans received
• Investment income or interest
• Reimbursements for expenses (if you're just passing costs through)

Real-World Example: When to Register

A freelance consultant starts their business on 1 January 2026.

• Jan–May: Invoices £70,000
• June: Invoices £25,000 — total now £95,000
• Result: Must register for VAT immediately in June (within 30 days)

What Happens If You Miss the Registration Deadline?

• HMRC will demand you charge VAT backdated to when you crossed the threshold
• If you've already invoiced clients without VAT, you now owe the VAT to HMRC from your own pocket
• Penalty: typically 5–15% of the VAT you should have collected
• Interest charges accumulate daily
• Your clients may refuse to pay the "late" VAT you now demand

This is why tracking your rolling turnover throughout the year is critical.

Voluntary Registration: Registering Below the Threshold

You don't have to wait until £90,000. You can register voluntarily at any turnover level if it makes business sense. Reasons to do this:

• Your clients are VAT registered — They can reclaim VAT you charge, so 20% extra doesn't deter them
• You make substantial business purchases — You can reclaim VAT on office rent, software, equipment, which recovers the VAT you'll charge customers
• You export goods or services — Export sales are often zero-rated, so registering lets you reclaim VAT on export-related costs
• You want to appear larger — Some clients view VAT registration as a sign of legitimacy

But voluntary registration has a downside: you're now locked in. You can't deregister for 2 years (unless turnover drops below £90,000), and your invoices are now more expensive for non-VAT-registered customers.

How to Register for VAT

Use HMRC's online service at gov.uk/register-for-vat. You'll need:

• Your business details (name, address, activities)
• Your recent turnover figures
• Bank details
• National Insurance number (sole traders) or Company Registration Number (limited companies)

Registration is typically approved within 2 weeks. Once approved, you receive your VAT Registration Number (VRN), which starts with GB and is 9 digits (e.g., GB 123 4567 89).

After Registration: Your Responsibilities

Once registered, you must:

• Charge VAT on invoices — 20% on standard-rated supplies (or appropriate rate)
• Submit VAT returns — Quarterly to HMRC, showing VAT charged minus VAT reclaimed
• Keep detailed records — Invoices, receipts, bank statements for 6 years
• Make sure customers pay VAT — On your invoices and in your accounts

The Challenge: Crossing the Threshold Mid-Year

If you cross £90,000 on, say, 15 July, you must register within 30 days — by 15 August. But what about invoices you've already issued without VAT in July?

You have two options:

1. Issue credit notes to those clients, then reissue invoices showing VAT
2. Ask clients to pay extra VAT — Rarely popular and may damage relationships

This is why tracking turnover monthly (not annually) prevents nasty surprises.

Track Your Threshold Easily

InvoiceForged automatically totals your invoices, so you can see your rolling 12-month turnover at a glance. Set a reminder when you approach £85,000, and you'll have time to prepare for VAT registration before the deadline hits. Create your first invoice free.

FAQ

What if my turnover dips below £90,000 after I register?

You're stuck registered for 12 months minimum. After that, if you've stayed below £83,000 for a year, you can apply to deregister.

Does retained profit count towards the threshold?

No. Only invoiced sales count. Profit is what's left after expenses.

What if I work across multiple businesses?

If you control related businesses, HMRC may combine their turnover for threshold purposes. You can't split businesses to stay below £90,000.

Can I retroactively register if I should have registered earlier?

Yes, but HMRC will back-calculate and you'll owe VAT from when you crossed the threshold. This can be expensive.