How much corporation tax could you save by buying a £50,000 piece of manufacturing equipment this year? If you are a limited company paying the main 25% rate, the answer is £12,500. That is the power of the Annual Investment Allowance (AIA), a UK tax relief that lets you deduct the full cost of qualifying plant and machinery from your taxable profits in the year you buy it.
A common mistake is assuming the AIA applies to everything you purchase for your business. It does not. Cars are excluded entirely, as are buildings and assets used for leasing. Even within plant and machinery, there are traps: a software licence bought as a monthly subscription does not qualify, only an outright perpetual licence does. For a manufacturing SME buying a new CNC machine, the full £50,000 would qualify. For a professional services firm fitting out a new office, the air conditioning and security systems qualify, but the structural walls and carpets generally do not.
The AIA limit for the 2025/26 tax year is £1 million. That means a business with a December year-end can spend up to £1 million on qualifying assets in that accounting period and claim 100% relief. If you spend £180,000 on a fleet of commercial vehicles (vans qualify; cars do not) and IT infrastructure for a growing team, you reduce your taxable profit by £180,000. At the 25% corporation tax rate, that is a £45,000 saving. If your business pays the small profits rate of 19%, the saving is £34,200.
What happens if you spend more than £1 million in a single accounting period? The excess goes into the main capital allowances pool and attracts writing-down allowances at 18% per year on a reducing balance basis. This is a common scenario for hospitality operators who open a new site and buy all the kitchen equipment, furniture, and fit-out in one go. The AIA covers the first £1 million; the rest is written down over several years.
Timing is everything. You must claim the AIA in the accounting period when you incur the expenditure. If your company's year-end is 30 September 2025 and you buy a new server in August 2025, you can claim it in that year's return. If you wait until October 2025, it falls into the next period. For a construction subcontractor planning to buy a new digger and a set of tools, pushing the purchase across a year-end can shift the tax saving by a full year. HMRC form for claiming is part of the company tax return, and you should keep detailed invoices and asset registers to support the claim.
For e-commerce sellers and independent retailers, the AIA is particularly valuable when scaling. Buying a warehouse racking system, a new delivery van, and a batch of high-end laptops for a remote team can all be claimed in the same year, provided the total stays under £1 million. The relief front-loads the tax benefit, reducing your corporation tax bill in the year of investment and freeing up cash flow for stock or marketing. If your business is a partnership or sole trader, the same rules apply, though the tax saving is at your marginal income tax rate rather than the corporation tax rate.