The Flat Rate Scheme was sold as a simplification: pay a single percentage of your VAT-inclusive turnover to HMRC, skip the box-by-box input/output reconciliation, keep whatever's left over as a bonus if your sector's rate happened to sit below what you'd have paid under standard VAT. For a lot of small service businesses still on it in 2026, that bonus stopped existing years ago, and nobody told them to leave.
How the scheme actually works
Instead of reclaiming input VAT on purchases and charging output VAT on sales separately, you charge your customers VAT normally (20% on standard-rated sales) but only pay HMRC a fixed percentage of your gross, VAT-inclusive turnover. The percentage depends on your trade sector, set out in HMRC's published table, ranging from around 4% for some retail sectors up to 14.5% for IT contractors and management consultants. You get a 1% discount in your first year of VAT registration.
You can't reclaim input VAT on day-to-day purchases at all under flat rate, only on capital assets costing £2,000 or more including VAT. The scheme is only available to businesses with taxable turnover (excluding VAT) of £150,000 or less to join, and you must leave once turnover exceeds £230,000.
The rule that changed everything: limited cost traders
Since April 2017, if your business spends less than 2% of its VAT-inclusive turnover on goods (not services) in an accounting period, or less than £1,000 a year if 2% would be a bigger figure, you're classed as a limited cost trader. That forces you onto a flat rate of 16.5%, regardless of what your actual sector rate would otherwise be.
This catches almost every consultancy, agency, contractor, or services business with a genuinely low cost base, which is most of them. Software developers, marketing consultants, bookkeepers, designers: if your main cost is your own time rather than materials, you're very likely a limited cost trader.
| Sales (VAT-inclusive), full year | £120,000 |
| Flat rate at 16.5% (limited cost trader) | £19,800 |
| Sales (VAT-exclusive) | £100,000 |
| Output VAT at 20% | £20,000 |
| Less: input VAT on real costs (say £6,000 net of expenses) | −£1,200 |
| VAT due under standard scheme | £18,800 |
In this example flat rate costs £1,000 more than standard VAT would, for a business with a modest but real amount of input VAT to reclaim. The gap widens further the more the business spends on VAT-able overheads: software subscriptions, a laptop, professional indemnity insurance with VAT on it, an office fit-out. Once you're a limited cost trader, flat rate is very rarely the cheaper option.
⚠️ The 2% test isn't optional and it's checked every period. You work out whether you're a limited cost trader separately for each VAT return, based on that period's spend. A business that occasionally buys enough stock to dip under the threshold in one quarter and above it in the next has to switch its rate accordingly, this is one of the most commonly missed compliance points on flat rate returns.
Where flat rate can still make sense
The scheme hasn't disappeared for a reason: it can still be worth it for businesses that:
- Genuinely spend more than 2% of turnover on goods, trades with real material costs (some retail, catering, certain building trades) can still land on a sector rate meaningfully below 20%, without being forced to 16.5%.
- Value the administrative simplicity more than the marginal saving, no need to track input VAT on every purchase, one number per quarter. This is a real benefit for a sole trader with no bookkeeping support, even if the cash saving is small or negative.
- Are in their first year of VAT registration, where the 1% discount can tip a marginal case into being worthwhile, worth reviewing again as soon as that discount year ends.
✓ How to check your own numbers: Take your last four VAT quarters' actual input VAT reclaimed under standard rules (or estimate it from your Xero purchase ledger) and compare it to the flat rate percentage applied to the same period's gross sales. If standard VAT would consistently come out lower, it's worth asking your accountant about switching, you can leave the flat rate scheme at the start of any VAT period.
What this means for VAT forecasting
Flat rate VAT doesn't map onto invoice-level input and output tracking the same way standard scheme VAT does. There's no real reclaim to calculate, just a percentage of turnover. If your accountant uses Rooby, you'll notice flat rate clients get a different treatment: the VAT figure is estimated from the trial balance's VAT control account rather than built line-by-line from invoices, credit notes, and bank transactions the way a standard-scheme client's is. It's flagged as unverified for exactly that reason, flat rate genuinely needs a different calculation method, not a simplified version of the standard one.
💡 Rooby tip: Rooby tracks which VAT scheme each client is registered under and adjusts how it calculates and labels their VAT figure accordingly: flat rate, cash accounting, and standard scheme clients each get a method suited to how their VAT actually works, rather than one number treated the same way for everyone.
The review worth having
If nobody has revisited your VAT scheme since you registered, that's worth fixing regardless of which way the numbers land. A five-minute comparison against your last year of actual purchase VAT is usually enough to tell you whether flat rate is still doing what it was meant to.
Rooby connects to Xero and calculates VAT using the method that actually fits how your business is registered: standard, cash accounting, or flat rate.