Annual Investment Allowance: Claim Back the Cost of Tools and Equipment

‍‌​‌‌‌‌​​‌​‌​‌‌​‌‌‌​​​​‌​​​​​‌​‌‌‍SiteKiln gives you plain-English information, not legal advice. If you need advice specific to your situation, talk to a qualified accountant or tax adviser.

The short version

AIA is a 100% upfront tax deduction for most plant and machinery -- vans (not cars), site kit, machinery, computers -- up to £1 million of spend per year. It sits in the Capital Allowances Act 2001; instead of spreading tax relief over 10-20 years, you claim the full qualifying cost in the year you buy it, which cuts this year's taxable profit.

Why it matters

In a good year, buying a van, mixer, scaffold or laser gear and claiming AIA can save you thousands in tax, right when cashflow is tight. Skip it, and you still get relief via normal writing-down allowances, but much slower -- not great if you're trying to fund growth or cover a chunky January bill.

Capital allowances are how the tax system gives relief on capital items -- things that last several years, like vans and machinery -- instead of treating them as day-to-day expenses. The Annual Investment Allowance is the main one most small construction businesses use: it lets a "qualifying person" (sole trader, partnership or company) deduct 100% of qualifying plant and machinery up to the annual cap.

5.11.1 What you can use AIA on

HMRC's capital allowances guidance and the Capital Allowances Act say AIA covers most plant and machinery, including:

• Vans and commercial vehicles (not normal cars).
• Plant and machinery -- diggers, mini-excavators, mixers, compactors, scaffold and access kit.
• Big tools and equipment -- table saws, dust extraction, compressors, generators.
• Office and site gear -- computers, printers, some office furniture.

AIA does not normally cover:

• Cars (these go through different capital allowance rules).
• Land, buildings or structural work (they may fall under other allowances like Structures and Buildings Allowance).

Most used kit and second-hand plant can still qualify, as long as you bought it for the business and you own it.

5.11.2 The current AIA limit

The law now locks the maximum AIA at £1,000,000 per year for qualifying spend.

In practice for a small builder:

• You add up all qualifying plant and machinery spend in your accounting year.
• If the total is £1m or less, you can usually AIA the lot.
• Only if you spend more than that do you have to push the excess into normal writing-down allowances.

If you run multiple businesses under common control (for example, several companies), they may have to share a single £1m pot between them.

5.11.3 How the claim actually works

On your tax return/accounts for the year:

• You identify the qualifying assets you bought -- for example, a van for £20,000 and plant for £8,000.
• You put those into your capital allowance section as "AIA qualifying expenditure".
• You claim AIA on as much of that as you want, up to the limit -- often the full amount for small trades.
• That AIA amount comes off your taxable profit, just like an expense.

For example:

• Profit before capital allowances: £60,000.
• Buy a van and kit for a total of £28,000.
• Claim AIA on the full £28,000.
• New taxable profit: £32,000.
• The tax saving is that £28,000 x your marginal tax/NIC rate doesn't get hit this year.

You don't have to claim AIA on everything -- sometimes an accountant will hold some back and use slower allowances if it helps smooth profits across years -- but most small builders just want the relief now.

5.11.4 Simple example for a small builder

Year's numbers:

• Turnover: £150,000.
• Running costs (fuel, small tools, materials, insurance, etc.): £90,000.
• Profit before capital allowances: £60,000.

During the year you buy:

• Used transit-style van: £18,000.
• New cement mixer and laser level: £2,000.
• Total AIA-qualifying plant and machinery: £20,000 -- well within the £1m limit.

You claim full AIA on the £20,000:

• Taxable profit becomes £60,000 - £20,000 = £40,000.
• At 20% income tax and with Class 4 NIC on top, you've probably saved several thousand in tax/NIC compared to not claiming.

The flip side: because you've taken all the relief now, you don't get capital allowance deductions for that van and kit in later years -- you've already had the benefit upfront.

5.11.5 Things to watch

A few points that catch people out:

• Personal use -- if you use an asset partly privately (for example, van used for holidays), you may need to restrict the claim to the business share.
• Cars vs vans -- HMRC are picky; what you call a van might be treated as a car for tax, which changes the relief.
• Timing -- AIA is claimed in the accounting period when you incur the cost, so timing big buys near year-end can change which year gets the relief.
• Multiple businesses -- if you have more than one business under your control, you may have to decide how to split one AIA limit between them.

If you're planning a big spend -- say, multiple vehicles or heavy kit -- it's worth getting an accountant to sense-check which bits qualify and the best year to buy them in.

What to do next

• Before buying a van or expensive kit, check with your accountant whether AIA applies and which tax year gives the best relief.
• Keep invoices for all plant and machinery purchases -- you will need them for your capital allowance claim.
• If the asset is used partly for personal use (like a van you drive at weekends), work out a fair business percentage.
• Make sure you are claiming AIA on your Self Assessment or company tax return, not just treating big purchases as lost money.

Sources and legislation

• Capital Allowances Act 2001 -- AIA rules, qualifying expenditure and the £1m permanent limit (section 51A). legislation.gov.uk/ukpga/2001/2
• Income Tax (Trading and Other Income) Act 2005 -- how capital allowances reduce self-employed trading profits. legislation.gov.uk/ukpga/2005/5
• Finance Act (various) -- amendments setting the AIA limit at £1,000,000. legislation.gov.uk/ukpga

Related guides on this site

• 5.6 Expenses you can claim
• 5.3 Filing Self Assessment -- construction-specific deductions
• 5.15 Record keeping
• 15.12 Should I get a van
• 8.1 Sole trader vs limited company -- honest comparison

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