There is a moment every scaling brand hits. You are checking the month's payouts, and the number at the bottom makes you stop. You add up the last twelve months in your head, then on a calculator, then in a spreadsheet because you do not trust the first two answers. And there it is. You have gone over £90,000.

I see this moment a lot. I am a specialist e commerce accountant, and I spend my days inside the VAT returns and settlement reports of brands that grew fast enough to cross the registration line without meaning to. The panic sets in at the same place every time: "Do I have to register? What happens to my prices? What about all the VAT I have not charged?"

Let me answer those properly. This is the UK VAT registration rulebook, but only the parts that matter when you are growing past the threshold. The numbers are HMRC's current ones, checked against gov.uk on the day this went out.

The Quick Summary

If your taxable turnover for the last 12 months goes over £90,000, you must register. You have 30 days from the end of the month you crossed the line. Your registration takes effect from the first day of the second month after you crossed it, and you owe VAT from that date, whether you charged it or not. Run your own numbers through our VAT registration checker before you panic.

There is a second trigger. If you expect your taxable turnover to go over £90,000 in the next 30 days alone, you must register by the end of that 30-day period. Same duty, earlier clock.

Once registered, you charge 20% on most sales, you file VAT returns through Making Tax Digital, usually quarterly, and you pay within one month and seven days of the period end. That is the whole machine. Everything else in this post is about the corners where brands trip.

The £90,000 Line

The threshold is £90,000 of taxable turnover, and it has been since 1 April 2024. "Taxable turnover" does not mean all your money. It means the value of everything you sell that is not VAT exempt or out of scope. Zero-rated, reduced-rated and standard-rated goods all count. Exempt sales, like most financial services and insurance, do not.

For an e commerce brand this matters more than it sounds. Zero-rated sales count in the test. So a brand doing £110,000 of turnover where £30,000 is zero-rated is over the line, because only exempt and out-of-scope sales, and most sales of capital assets used in the business, drop out of the number. Get the split wrong and you think you are safe when you are not, or you register in a panic you did not need.

The test is a rolling one. Every month you look back 12 months, not calendar years, not your financial year, the 12 months ending now. That is why a single viral month can tip you over: you do not get to wait for your year end. A one-off spike still triggers the normal test, and the escape route for it is a separate application, not a box on the form. If the trailing 12 months is over £90,000, the duty is live.

Two more things belong in this section. First, voluntary registration. You can register below the threshold, and plenty of brands should, because you cannot reclaim VAT on your costs without a registration. If you are spending heavily on fees, software and stock at £70,000 of sales, it can be the single best number in your accounts. Second, if your sales are mostly zero-rated, you can apply for an exemption from registration, but you have to ask HMRC. It is not automatic.

How the Clock Actually Runs

The timing rules are precise, and they are the bit most founders get wrong, so here is the worked version straight from HMRC's guidance.

Say on 15 July your trailing 12-month taxable turnover hits £100,000, the first time it has gone over the threshold. You must register by 30 August, within 30 days of the end of the month you crossed. Your effective date of registration is 1 September, the first day of the second month after you went over. From 1 September you charge VAT, and that is the date HMRC counts from.

Now the future test. Say on 1 May you sign a contract worth £100,000 that lands at the end of the month. You know you will exceed £90,000 within 30 days. You must submit your registration by 30 May, and your effective date is 1 May, the date you realised, not the date the money arrived. This one catches service businesses and wholesale deals more than consumer brands.

Register late and the bill is the same shape, only worse. You owe VAT on every sale back to the date you should have registered, even though you never added it to your prices. On top of that you can face a penalty based on how much you owe and how late you are. I have seen brands eat a six-figure VAT bill they never collected, because nobody watched the rolling 12-month number. That is the whole game in one sentence: the threshold is not a surprise, it is a number you are responsible for watching.

One genuine escape hatch exists, and it is underused. If you went over the threshold but you can show your taxable supplies will not go over £88,000 in the next 12 months, you can apply for an exception from registration. HMRC considers it and writes to you, usually within 40 working days. This is for genuine spikes. If you are trending up, you will not pass it: apply for nothing, register, and move on.

What Changes the Day You Register

Registration is not a tax bill, it is an operating change. Here is what actually happens.

You charge VAT at the correct rate on your taxable sales. That is 20% standard on most products, 5% reduced on things like domestic fuel and children's car seats, and 0% on qualifying exports and most food. Exempt and out-of-scope sales carry no VAT at all. When you issue a full VAT invoice, it must show your VAT number and the VAT separately, while simplified invoices under £250 have lighter rules. Your prices become VAT-inclusive in the customer's eyes, and here is the maths that trips everyone: on £100 of customer takings the VAT inside is £16.67, not £20. Twenty percent is what you add to a VAT-exclusive price. One sixth is what you strip out of an inclusive one. A brand doing £1m of customer takings, all standard-rated, carries £166,667 of VAT in that number, and if your accountant is doing the maths at £200,000, your cashflow forecasts are wrong by £33,333 before you start.

You keep digital records and file through Making Tax Digital. Every VAT-registered business is in scope now, whatever its turnover, unless HMRC has granted an exemption, and it means software, not spreadsheets by hand. The ways this goes wrong, and the enquiries they trigger, are in our MTD mistakes post. Your returns usually go in quarterly, and payment lands one month and seven days after the period ends. Miss returns and you earn penalty points: quarterly filers reach a £200 penalty at four points, plus £200 for every further late return while they stay at the threshold. Pay late and you owe interest, currently 7.75% a year, Bank Rate plus four points. If HMRC is late repaying you, you get repayment interest at 2.75%, Bank Rate minus one point. The asymmetry is the point: they charge you more than they pay you.

You also start reclaiming. Input VAT on your costs, platform fees, software, shipping, marketing, stock, most of it becomes reclaimable where it carries VAT, supports your taxable sales, and you hold the evidence. Some costs never qualify, and some suppliers do not charge UK VAT at all. If you are buying stock and paying fees while sales are still ramping, the reclaim side can be bigger than the output side in the early years, which is why registration is often a cash win, not a cost. The mistake is treating VAT as a pure expense line. For a healthy brand most of it washes through the VAT control account, and the skill is in the timing of the return, not the dread of it. The limits that apply live in our guide to claiming VAT back.

The Three Schemes That Soften the Blow

Three HMRC schemes exist for smaller registered businesses, and each one changes your VAT economics. Know all three before you file your first return.

First, the Flat Rate Scheme. You pay a flat percentage of your VAT-inclusive turnover instead of doing the full output minus input calculation. You can join if you expect your VAT-exclusive taxable turnover for the next 12 months to be £150,000 or less, and you normally have to leave once your VAT-inclusive income goes over £230,000. If you are a "limited cost" business, one that spends less than 2% of its flat rate turnover on goods, or more than 2% but under £1,000 a year (that is £250 for a normal quarter), the rate is a flat 16.5% and you give up your input VAT reclaims except on a single purchase of qualifying capital expenditure goods costing £2,000 or more including VAT.

Here is my contrarian take. For a physical-goods e commerce brand, the Flat Rate Scheme is usually a bad deal dressed as a simplification. On £180,000 of standard-rated inclusive takings, the normal output VAT is £30,000. At the 16.5% limited cost rate you pay £29,700. The scheme saves you £300 before you count a single reclaim, and you give up reclaiming the VAT on your costs to get it. You tend to win only if your reclaims are tiny, which is true for service and digital businesses, not for brands buying stock and running ads. And the trap is quiet: platform fees and ad spend are services, not "goods" for the 2% test, so a brand with heavy service costs can find itself classed as limited cost with a 16.5% rate and no reclaims to offset it. Do the 12-month maths before you join, not after.

Second, Cash Accounting. You pay VAT to HMRC when your customers pay you, and you reclaim when you pay your suppliers. For a brand selling on marketplaces with settlement cycles, this can smooth genuinely painful cash timing. Join at £1.35m of expected taxable turnover or less, and you normally have to leave at the end of the VAT period in which your taxable turnover for the last 12 months goes over £1.6m. Most scaling brands outgrow it, but in the £100k to £500k zone it is a real cashflow tool, not a gimmick.

Third, Annual Accounting. One return a year instead of four, with advance payments spread through the year and a balancing payment or refund when the annual return lands. Join at £1.35m or less. It suits brands with stable, predictable VAT, and nobody who is regularly reclaiming: you only get one refund a year.

The Marketplace Wrinkle

If you sell through Amazon, TikTok Shop or another marketplace, there is a layer of rules on top of the threshold, and getting it wrong means you either pay VAT twice or you miss it entirely.

For a UK-established seller with stock in the UK selling to UK consumers, the marketplace is not responsible for the VAT. You are. The platform may process the customer's VAT-inclusive payment, but the output VAT is yours and the sales count in your threshold test like any other sale. That is the default position and it covers most of the brands reading this.

The marketplace becomes the responsible party, the deemed supplier, in two situations. Non-excise goods outside the UK at the point of sale, sold to a consumer in Great Britain in a consignment with an intrinsic value of £135 or less, the marketplace charges and accounts for the UK VAT at checkout, unless a VAT-registered business customer gives a valid UK VAT number, in which case different rules apply. And goods already in the UK sold through a marketplace by an overseas seller to a UK consumer, whatever the value: there the marketplace accounts for the VAT, and the overseas seller makes a zero-rated supply to the platform.

Why does this matter for your threshold? Because for a UK-established seller, the sales that count in your £90,000 test are the taxable supplies you make. Your ordinary UK sales through marketplaces count. Where the marketplace is the deemed supplier, that sale is not a taxable supply you make, and the VAT on it never enters your return. They are still your income, but they are not the sales that push you over the £90,000 line. (The picture is different for overseas sellers, who face separate registration rules with no £90,000 threshold.) I have had this exact conversation with founders whose marketplace handles part of their range through the import route: their VAT registration picture is different from their revenue picture, and both need to be right. The full who-accounts-for-what breakdown, with the scenarios laid out side by side, is in our marketplace VAT deep dive.

Imported Stock and the VAT You Do Not Pay Twice

Growing brands import. And import VAT is the most misunderstood number in e commerce accounting.

When you bring goods into Great Britain from outside the UK, import VAT is due at the UK rate. But if you are VAT-registered you do not have to pay it upfront at the border and claw it back later. You can use postponed VAT accounting, which lets you declare the import VAT due and recover the allowable amount on the same return, with no approval needed. Normal reclaim rules still apply, so the two amounts are not always equal, and anything you cannot recover stays a cost. Your agent or freight forwarder selects it on the import declaration, and it is your written instruction that tells them to.

This is a cashflow gift and most newly registered brands do not know it exists. Before you registered, import VAT was a cost you carried, with one exception: once you are registered, you can reclaim the VAT on goods bought in the previous four years if you still hold them, and on services bought in the previous six months. After you register, import VAT becomes a timing item to the extent it is recoverable. If your supplier ships from China, your freight forwarder should be hearing the words "postponed VAT accounting" from you this quarter. The distinction between import VAT on your stock and the VAT treatment of the goods themselves, including landed costs, is covered in our landed cost guide, because the two get conflated in every forecast I read.

The Mistakes I See Every Week

Here is the shortlist of what actually breaks, drawn from real client files.

Watching nothing. No one tracks the rolling 12-month figure monthly, so registration happens late, and late registration means VAT you never collected plus penalties. It takes one line in your monthly management accounts.

Doing the maths at 20% on inclusive takings. The VAT inside customer takings is one sixth. A £1m brand miscounted at £200,000 instead of £166,667 is a £33,333 forecasting error, and that is before your accountant notices the return does not tie to the bank.

Forgetting zero-rated exports. Goods you export from Great Britain to outside the UK are usually zero-rated, which means you still account for them but at 0%, if you hold the evidence HMRC requires. Brands that fail to document exports can end up paying VAT on sales that should have been zero-rated. The paperwork is the price of the zero rate.

Assuming the marketplace fixed it. For a UK-established seller, if the platform collects VAT on a sale as deemed supplier, that VAT is not on your return and the sale is not in your threshold test. If it does not, you owe it. The answer turns on where you are established, where the stock is and who the customer is, so check each channel against the rules in the marketplace section above before you assume anything.

Pricing without the VAT line. When you register, your prices need to absorb or display VAT, and your marketplaces handle this differently. Do the repricing before the effective date, not after the first return. Our guides for Shopify sellers, Amazon sellers and TikTok Shop sellers walk through each platform's VAT mechanics in practice, because the settings genuinely differ on all three.

Frequently Asked Questions

My turnover went over £90,000 for one month only. Do I still have to register?

If your trailing 12-month taxable turnover is over £90,000, the duty exists regardless of why. But if you can show it will not go over £88,000 in the next 12 months, you can apply for an exception from registration and HMRC will decide. Genuine one-off spikes are what that route is for.

Can I register before I hit £90,000?

Yes. You cannot reclaim VAT on your costs without a registration, so if your fees, stock and marketing spend carry significant VAT, registering early can put cash back in your account. The catch is the admin and the obligation to charge VAT from the effective date.

What happens to the VAT I never charged before registering?

If you registered on time, nothing. You owe nothing on pre-registration sales. If you registered late, you owe VAT on sales back to the date you should have registered, from your own pocket, plus possible penalties. The line between those two outcomes is one monthly check.

Are my marketplace sales counted in the threshold test?

Your own UK sales through marketplaces count, because you account for the VAT on them. Sales where the marketplace is the deemed supplier, like low-value imported consignments, do not count towards your own registration, because the platform accounts for that VAT. Your income and your VAT picture are two different maps.

Do I have to use Making Tax Digital software?

Yes. Every VAT-registered business files through MTD-compatible software with digital records, whatever its turnover. Spreadsheets are allowed, but they need compliant bridging software. Exemptions exist only in narrow cases, like genuine digital exclusion, not by size.

Can I deregister later if my sales fall?

Yes. You can ask HMRC to cancel your registration if you can show your taxable turnover for the next 12 months will stay below £88,000, the deregistration threshold. Cancellation is not automatic, and you may have to account for VAT on stock and capital assets you still hold, so it is a planned move, not a reaction.

The Bottom Line

The £90,000 threshold is not a punishment and it is not a surprise. It is a line you cross, a clock that starts, and a set of rules that are all published, all current and all learnable in an afternoon.

Watch the rolling 12-month number every month. Tell HMRC within 30 days of the end of the month you cross. Understand that the VAT inside your takings is one sixth, not a fifth. Sort your schemes before your first return, not after your second. And if your marketplace handles part of your VAT, know exactly which sales are yours and which are theirs.

Do that and registration stops being a tax event and becomes what it actually is: the moment your business started paying its way properly. Do it late and you are paying for VAT you never collected, which is the most expensive lesson in e commerce accounting. I have watched too many good brands learn it the hard way.

If you are approaching the threshold, or you crossed it and your books are not ready, book a call and we will run your numbers through the threshold test, check your schemes and get your registration date right before HMRC does it for you. See how we help Shopify sellers, Amazon sellers and TikTok Shop sellers.