VAT registration is the milestone every growing small business eyes nervously, because it changes how you price, what you charge clients, and how much admin you carry. Register too late and HMRC can hit you with penalties and a backdated bill; register too early and you may add 20% to your prices for no reason. Knowing exactly when you must — and when you might choose to — is essential. Here is the 2025/26 picture in plain terms.
- You must register once VAT-taxable turnover passes £90,000 in any rolling 12 months.
- It is a rolling 12-month test, not your accounting year — watch it continuously.
- You can register voluntarily below the threshold, which sometimes pays.
- The Flat Rate Scheme can simplify VAT for smaller businesses, but check the limited-cost trader trap.
The £90,000 threshold
You must register for VAT if your VAT-taxable turnover exceeds £90,000 in any rolling 12-month period, or if you expect to cross it within the next 30 days. "VAT-taxable turnover" means your total sales that are not exempt — for most businesses, simply your sales.
It is a rolling test, not your tax year The single biggest mistake is checking turnover only at the financial year end. The £90,000 test applies to any consecutive 12 months. A strong few months can push you over mid-year, and you must register within 30 days of realising you will exceed it. Miss the deadline and HMRC can charge penalties plus the VAT you should have collected.
Once registered, you charge VAT (usually 20%) on your sales, hand it to HMRC, and reclaim the VAT on your business purchases. The VAT calculator handles adding and removing VAT from any figure.
What registration actually changes
Crossing the threshold has real consequences:
- You add 20% to your prices (or absorb it, cutting your margin) — a big deal if your customers are the public and cannot reclaim VAT.
- You can reclaim VAT on equipment, stock and expenses, which helps if you buy a lot.
- You take on quarterly VAT returns under Making Tax Digital, needing compatible software.
For a business selling to other VAT-registered businesses, registration is often neutral or even helpful — your clients reclaim the VAT you charge, and you reclaim yours. For a business selling to consumers, it can mean a real 20% price rise or margin hit, which is why some deliberately manage turnover near the threshold.
Voluntary registration: when it pays
You can register below £90,000 if you want to. It makes sense when:
- Your customers are mostly VAT-registered businesses who reclaim the VAT, so your prices effectively do not rise for them.
- You spend heavily on VATable costs — equipment, stock, software — and want to reclaim that input VAT.
- You want the credibility of looking like an established, larger business.
It is a poorer idea if you sell to consumers and buy little, since you would be adding 20% to your prices with little to reclaim.
The Flat Rate Scheme and its trap
Smaller registered businesses can use the Flat Rate Scheme (FRS) to simplify VAT: you charge 20% as normal but pay HMRC a fixed, lower percentage of your gross turnover, instead of tracking VAT on every purchase. It cuts admin and can leave a small surplus.
Beware the limited-cost trader rate If you spend very little on physical goods — typical of consultants and service businesses — you are classed as a "limited cost trader" and must use a high 16.5% flat rate, which is rarely worthwhile. Many people join the FRS expecting their sector's lower rate, only to be caught by this. Check carefully before opting in; the VAT calculator lets you compare the schemes.
Deregistration
It works the other way too. If your turnover falls below £88,000, you can apply to deregister and stop charging VAT — useful if you scale back. Keeping an eye on the rolling figure cuts both ways.
This sits alongside your other business taxes — see the corporation tax calculator for company profits and the sole trader vs limited comparison if you are weighing your structure.
Frequently asked questions
Once your VAT-taxable turnover exceeds £90,000 in any rolling 12-month period, or when you expect to exceed it within the next 30 days. You must register within 30 days of realising you will cross it.
No. It is a rolling 12-month test, so you must monitor turnover continuously, not just at your year end. This catches many growing businesses out.
It can pay if your customers are VAT-registered businesses or you spend heavily on VATable costs you can reclaim. It is usually a poor idea if you sell to consumers and buy little.
A simplified VAT method where you pay HMRC a fixed percentage of gross turnover instead of tracking VAT on every purchase. Watch the 16.5% limited-cost trader rate, which applies if you buy few physical goods.
Yes. If your turnover falls below £88,000 you can apply to deregister and stop charging VAT.
Figures are 2025/26 estimates. VAT rules are detailed and the penalties for getting registration wrong are real — take accountancy advice if you are near the threshold.