The de minimis test — a beginner's guide to one of UK VAT's quirkier rules

If your business has any exempt income at all — residential lettings, certain types of training, financial services, some healthcare — you might be partially exempt for VAT. The de minimis test is the rule that determines whether the partial-exemption complexity actually applies to you, or whether HMRC will let you off and recover all your input VAT anyway.

It's also one of the more counter-intuitive tests in UK VAT. Worth understanding even if you think you're standard-rated.

Exempt vs zero-rated vs outside the scope

Three terms that get confused, often in the same conversation:

• Standard-rated supplies attract VAT at 20% (or the reduced rate of 5%). Examples: most goods and services.
• Zero-rated supplies are taxable but charged at 0% VAT. Examples: most food, children's clothes, books. The business can still recover VAT on costs.
• Exempt supplies don't attract VAT at all. Examples: residential rent, certain types of education, financial services, some healthcare. The business cannot recover VAT on costs that relate to making exempt supplies.
• Outside the scope supplies aren't UK supplies for VAT purposes. Examples: services to overseas business customers under the place-of-supply rules.

The critical distinction for partial exemption is exempt vs zero-rated. A zero-rated business — like a children's clothes retailer — recovers all its input VAT despite charging no output VAT, because the supplies are taxable (just at 0%). An exempt business — like a residential landlord — can't recover input VAT, because the supplies aren't taxable at all.

If your business makes both taxable supplies (standard or zero-rated) AND exempt supplies, you're partially exempt.

Who is partially exempt without realising it

Common cases:

• Charities with trading subsidiaries — the charitable activities are often exempt, the trading is taxable
• Property businesses — commercial lettings can be opted to tax (becoming standard-rated), residential lettings are exempt; mixed portfolios trigger partial exemption
• Medical practices — clinical services are exempt, but pharmacy retail or dispensing of certain goods is taxable
• Financial services firms — most financial intermediation is exempt, but ancillary services like consultancy or training may be taxable
• Education providers — tuition is often exempt, but commercial conferences and trading activities are taxable
• Holiday-let operators — long-term lettings are exempt, short-term are taxable; mixed-use causes problems

If any of these describes your business, you're affected by partial exemption, and the de minimis test is the first thing to check.

The simplified de minimis test (Test 1)

The simplified test was introduced to spare small businesses from the full partial exemption rigmarole. You pass Test 1 if both:

• Total input tax is no more than £625 per month on average (i.e. £1,875 per quarter or £7,500 per year), AND
• Exempt input tax is no more than half of total input tax

If you pass Test 1, you can recover all your input VAT — including the bit that relates to exempt supplies — and you're done. You don't have to do the full partial exemption calculation.

For very small businesses (a residential landlord with one or two flats and no other income, for example), Test 1 is often all that's needed.

The full de minimis test (Tests 2 and 3)

If you fail Test 1 — usually because your input tax is too high — you fall into the standard partial exemption regime. You calculate your recoverable VAT using the standard method (or simplified method, or special method if HMRC has approved one), and the de minimis test reappears in two further forms.

Test 2: exempt input tax (after the partial exemption calculation) is no more than £625 per month on average AND no more than 50% of total input tax. If you pass, you recover everything. If you fail, only the recoverable proportion plus any directly-attributable taxable input tax can be reclaimed.

Test 3: A separate test based on residual input tax. Specifically, you pass if total input tax minus directly-attributable-to-taxable input tax is no more than £625 per month and no more than 50% of total input tax.

Tests 2 and 3 are alternatives. Pass either one and you can recover all your VAT.

Worked example

Imagine a small medical practice with an attached pharmacy:

• Total input VAT for the year: £8,000 (£667/month average)
• Input VAT directly attributable to taxable supplies (pharmacy products): £3,000
• Input VAT directly attributable to exempt supplies (medical equipment): £1,000
• Residual input VAT (rent, utilities, admin): £4,000

Test 1: Total input VAT averages £667/month — fails the £625 limit. So Test 1 doesn't apply.

Run the standard method calculation. Suppose the recovery percentage based on supply values is 35%. Recoverable residual = £4,000 × 35% = £1,400. Non-recoverable residual = £2,600.

Test 2: Exempt input tax = £1,000 (directly attributable to exempt) + £2,600 (non-recoverable residual) = £3,600. Average per month = £300. That's under £625, but is it under 50% of total? £3,600 ÷ £8,000 = 45%, also under 50%. Test 2 passes. The practice can recover all £8,000 of input VAT.

If the recovery percentage had been 25% instead of 35%, the figures would have been different and Test 2 would likely have failed. The practice's mix of supplies determines whether de minimis applies.

The annual de minimis test

Each VAT period's de minimis tests are provisional. At year-end, the same tests are applied to the full year's figures. If a business has been provisionally treated as de minimis during the year but fails the annual test, the annual adjustment claws back the over-recovered VAT.

This is where the trap lies. A business that passes de minimis in three quarters and fails marginally in the fourth, or that grows its exempt income during the year, can find that the annual recalculation triggers a clawback. The provisional treatment was correct quarter-by-quarter but wrong overall.

When it's worth changing your mix

Some partially exempt businesses deliberately manage their mix of supplies to stay below the de minimis thresholds. This is legitimate planning, not avoidance. Examples:

• Timing major capital expenditure to fall in years when exempt supplies are below the threshold
• Re-classifying borderline supplies (e.g. opting to tax a commercial property to bring it within taxable supplies)
• Restructuring activities into separate VAT-registered entities so that each one is independently standard-rated

These decisions aren't right for every business. They depend on cash flow, simplicity, and whether the cost of partial exemption administration outweighs the recovery benefit.

A simple flowchart

If you're trying to figure out whether you're partially exempt and what to do about it:

1. Do you make any exempt supplies (residential rent, financial services, healthcare, education, etc.)? If no, you're not partially exempt. Stop.
2. Is your total input VAT under £625/month on average? If yes, run Test 1.
3. Test 1: is exempt input tax under 50% of total? If yes, you're de minimis. Recover everything.
4. If no to step 2 or 3, run the partial exemption calculation (Standard, Simplified, or Special Method).
5. After the calculation, run Tests 2 and 3 on the figures. If either passes, you recover everything.
6. If both fail, you can only recover directly-attributable taxable input VAT plus the recoverable proportion of residual.
7. Repeat the whole exercise at year-end with full-year figures.

The whole thing is more conceptually consistent than it first appears. The complications are in the calculations themselves, not in the framework.

Where this gets hard

The framework is teachable in an afternoon. Doing it cleanly across multiple VAT periods, with transactions moving in the ledger, with the annual recalculation, and with the audit trail intact — that's the part that takes years of practice. It's also the part that the standard accounting platforms don't help with.

That's the gap that specialist tools like OneSixth exist to fill. But the framework itself is just maths and rules. Anyone can learn it.