How to Switch VAT Scheme, and When You Are Allowed To

A business rarely picks its VAT scheme once and never revisits it. Turnover grows, the customer base shifts from consumers to other businesses, expenses rise or fall, and the scheme that fitted at registration stops fitting. The problem is that moving between schemes is not something you can do casually at any point in the year. Each scheme sets its own rules on when you can join, when you must leave, and how much notice HMRC expects, and the VAT accounting schemes hub sets out how the individual schemes work before you weigh up a change.

The mechanics of switching matter because two of the common mistakes are expensive. One is assuming you can leave the Flat Rate Scheme the moment it stops paying, when in practice a decision to join commits you for a period. The other is missing a mandatory exit and carrying on with a scheme you are no longer entitled to use, which stores up a correction and possible interest. This guide covers the timing and the notice for each of the three main schemes.

Standard accounting is the default you switch from and back to

Standard, or accrual, VAT accounting is the baseline. When you register you are on it unless you elect into a scheme, and when you leave any of the optional schemes you return to it. That matters for timing, because the question is rarely "can I switch schemes" in the abstract, it is "can I leave the scheme I am on" and "can I join the one I want". The two halves have separate rules and separate thresholds, and a switch only completes when both line up cleanly at the start of a VAT period.

Joining and leaving the Flat Rate Scheme

The Flat Rate Scheme is the one with the tightest timing rules, and it is where most switching questions arise. You can apply to join if your VAT-exclusive taxable turnover is expected to be £150,000 or less in the next 12 months. You apply in writing or through your VAT online account, and you cannot backdate entry to before the start of the current VAT period. Whether the scheme is worth joining in the first place is a separate calculation, covered in the guide on whether the Flat Rate Scheme still pays in 2026.

Leaving is where the trap sits. You can leave the Flat Rate Scheme voluntarily at any time by writing to HMRC, but once you leave you cannot rejoin for 12 months. That one-year lock is what catches businesses that jumped in, found their expense profile had changed, and wanted to switch back and forth to suit each year. You also have to leave, rather than choose to, in defined circumstances.

• On the anniversary of joining, if your total VAT-inclusive income in the past 12 months was more than £230,000, or you expect it to be more than £230,000 in the coming 12 months.
• At any point in the year if you expect your total VAT-inclusive income in the next 30 days alone to exceed £230,000.
• If you become ineligible for another reason, for example joining a VAT group.

There is one relief on the anniversary test. If your income for the year has gone over £230,000 but you can satisfy HMRC that it will fall below £191,500 in the coming year, you may be allowed to stay on the scheme with their agreement. The exit and re-entry conditions are set out in HMRC guidance on changing your Flat Rate Scheme circumstances, and the wider small-business position is explained plainly by the Low Incomes Tax Reform Group.

Joining and leaving the Cash Accounting Scheme

Cash accounting is the easiest to move in and out of, because there is no application and no notification. You can start using it from the beginning of a VAT period provided your VAT taxable turnover is £1.35 million or less and your returns and payments are up to date. You do not tell HMRC; the choice simply shows in how you prepare the return. The mechanics and the businesses it suits are covered in the guide on the cash accounting scheme and cash flow.

You must leave once your VAT taxable turnover exceeds £1.6 million at the end of a VAT period, and you can also leave voluntarily at the end of any period. Leaving carries a specific catch-up: you have to account for the VAT on all invoices that are still unpaid at the point you leave. You can normally spread that outstanding VAT over six months, unless your taxable turnover in the previous three months was over £1.35 million, in which case it falls due at once. That catch-up is the practical reason to plan a move away from cash accounting rather than trip into it.

Joining and leaving the Annual Accounting Scheme

The Annual Accounting Scheme, which replaces four returns a year with one plus interim payments, is joined by application where your estimated VAT taxable turnover for the next 12 months is £1.35 million or less. You must leave once turnover is, or is expected to be, more than £1.6 million at the end of the annual accounting year. Because the scheme runs on a fixed annual cycle with instalments set against an estimate, a switch out mid-year means reconciling what you have paid on account against what is actually due, so the cleanest point to change is at the end of an accounting year.

Getting the timing right

The common thread across all three schemes is that changes take effect from the start of a VAT period, not part way through one, and that a mandatory exit is not optional once its threshold is crossed. Three practical points cover most switches.

None of the switches changes how you keep records or file. Whichever scheme you are on, you still keep digital records and submit through Making Tax Digital for VAT in the normal way; a scheme change alters the calculation and the timing, not the filing route.

Common questions about switching VAT scheme

Can I switch VAT scheme whenever I want?

Not at any moment. A change generally takes effect from the start of a VAT period, and each scheme has its own entry and exit rules. Cash accounting can be adopted or dropped from the start of a period with no notice, but the Flat Rate Scheme has a 12-month bar on rejoining after you leave, and annual accounting is cleanest to leave at the end of its yearly cycle.

Do I have to tell HMRC when I change scheme?

It depends on the scheme. You apply to join the Flat Rate and Annual Accounting schemes and write to leave them, so HMRC is involved. Cash accounting needs no notification either way; you simply start or stop using it from the beginning of a VAT period, provided you are eligible.

How long am I locked into the Flat Rate Scheme?

You are not locked in from leaving; you can give notice to leave at any time. The lock is on the way back. Once you have left the Flat Rate Scheme you cannot rejoin it for 12 months, so a decision to leave should be treated as one you will keep for at least a year.

What happens to unpaid invoices if I leave cash accounting?

You account for the VAT on invoices still unpaid at the point you leave. This can usually be spread over six months, unless your VAT taxable turnover in the previous three months was over £1.35 million, in which case the outstanding VAT is due straight away.

A scheme that fitted at registration can quietly become the wrong one as a business grows, and the cost of switching badly is either a 12-month lock or a backdated correction. A VAT accountant can check which scheme now suits your turnover and payment patterns, time the move to a clean period start, and handle the entry, exit and any catch-up so the change does not create a bill you did not plan for. Our Flat Rate Scheme service is the usual starting point for that review.