Annual investment allowance explained for small businesses
Buying kit for your business? The annual investment allowance can cut your tax bill in the year you spend.
Written by Naomi Lai— Small business & finance writer. Read Naomi's full bio
Published Wednesday 23 September 2026
Table of contents
Key takeaways
- The annual investment allowance lets you deduct the full cost of qualifying equipment from your taxable profits in the year you buy it.
- The limit is £1 million per year, so most small businesses can claim on everything they buy.
- Most plant and machinery qualifies, including tools, computers, and vans, but not cars.
- Sole traders, partnerships, and limited companies can all claim the annual investment allowance.
What is the annual investment allowance?
The annual investment allowance (AIA) is a type of tax relief that lets you deduct the full cost of qualifying equipment from your profits before tax. You get the whole deduction in the year you buy the item, rather than spreading it across several years.
It sits within a wider group of AIA capital allowances, which are the rules that decide how business purchases affect your tax. You can read the full HMRC guidance on the annual investment allowance on GOV.UK. Sole traders, partnerships made up of individuals, and limited companies can all use it.
What's the annual investment allowance limit?
The annual investment allowance limit is £1 million a year. This figure was made permanent by the Finance (No. 2) Act 2023, so you can plan ahead without worrying it'll drop.
Most small businesses spend well under that cap, which means you can usually claim the full cost of everything you buy. Bringing that relief forward can make cash flow management easier in the year you invest. If your accounting period is shorter or longer than 12 months, the limit is scaled to match. For example, a nine-month period gives you a limit of £750,000.
What qualifies for the annual investment allowance?
Most plants and machinery you buy for the business qualifies. These are the everyday items that help you do your work. Common examples include:
- tools and equipment
- machines used in your work
- computers and office technology
- office furniture such as desks and chairs
- vans and lorries
- some fixtures and integral features in a building
What doesn't qualify for the annual investment allowance?
Some purchases fall outside the annual investment allowance, so you can't claim the full cost in one go. You'd usually use writing down allowances for these instead, which let you deduct a set percentage of the value each year and sit within the wider capital allowances rules. The main items that don't qualify are:
- cars of any kind
- items you owned for another reason before using them in the business
- items given to you or the business as a gift
How does the annual investment allowance work?
You add up what you spend on qualifying items, then deduct that total from your profits before you work out the tax you owe. Say you buy £20,000 of qualifying equipment in a tax year. You deduct the full £20,000 from your profits that year, which lowers the amount of profit you pay tax on.
Timing matters, because you can only claim in the accounting period in which you bought the item. The purchase date is when you signed the contract, or when payment is due if that's more than four months later.
If you're a sole trader or in a partnership and you use an item partly for personal reasons, you reduce the claim to cover business use only. A laptop used 80% for work, for instance, means you claim 80% of its cost.
Annual investment allowance vs full expensing
The difference in full expensing versus AIA comes down to who can claim and what they can buy. The annual investment allowance is open to sole traders, partnerships, and companies, covers new or used items, and lets you deduct up to £1 million a year.
Full expensing works differently and suits some limited companies, and the rules for full expensing are set out on GOV.UK. Here's how it compares:
- Full expensing is for companies only, so sole traders and partnerships use the annual investment allowance instead.
- It gives a 100% deduction on new and unused main-rate plant and machinery, with no upper limit.
- It adds a 50% first-year allowance on new special-rate assets, such as integral features.
- It covers assets bought from 1 April 2023 that are new and unused, and it excludes cars, used items, and leased items.
How to claim the annual investment allowance
Claiming is part of your normal tax return, and good records make it straightforward. Follow these steps to claim capital allowances for your small business.
1. Keep your records and receipts
Hold on to invoices and receipts for every qualifying item you buy. These show what you spent and when, which is exactly what you need at tax time.
2. Work out your qualifying spend
Add up the cost of all the qualifying items you bought in the period. Strip out anything that doesn't qualify, such as cars, and reduce for any private use.
3. Claim on your tax return
Enter the total on your Self Assessment tax return if you're a sole trader or partnership. If you run a limited company, you claim on your Company Tax Return instead.
4. Keep the figures for HMRC
Store your calculations and evidence in case HMRC asks to see them. Solid record-keeping through the year keeps everything to hand and saves you a scramble later.
Simplify your business finances with Xero
Claiming the annual investment allowance is far easier when your records are tidy and up to date all year. Accurate figures mean you can see exactly what you've spent on equipment and claim with confidence. Online accounting software keeps your receipts, purchases, and reports in one place, so your qualifying spend is ready when you file.
FAQs on the annual investment allowance
Here are quick answers to some common questions about the annual investment allowance.
Can sole traders claim the annual investment allowance?
Yes, sole traders can claim it, and so can partnerships made up of individuals. You claim through your Self Assessment tax return rather than a company return.
Do cars qualify for the annual investment allowance?
No, cars never qualify, whatever their emissions or use. You claim tax relief on business cars through writing down allowances instead.
Can you claim AIA on used or second-hand equipment?
Yes, the annual investment allowance covers used and second-hand items as long as they're new to your business. This is one area where it's more flexible than full expensing.
What happens if you spend more than the £1 million AIA limit?
You claim the allowance on the first £1 million of qualifying spend, then use writing down allowances on the rest. Very few small businesses reach the cap in a single year.
Is the annual investment allowance the same as full expensing?
No, they're separate reliefs with different rules. Full expensing is for companies buying new and unused kit, while the annual investment allowance is open to sole traders, partnerships and companies buying new or used items.
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