Why capital allowances matter to your bottom line

When you buy equipment for your business — a laptop, a delivery van, a new oven for the kitchen — the taxman generally won't let you deduct the whole cost from your profits in one go as an ordinary business expense. Instead, you claim capital allowances, which chip away at the cost over time and reduce your taxable profit. The relief is real money back, and for many small businesses it's one of the simplest ways to cut a tax bill. The trick is knowing what you can claim, how quickly, and where the rules get fiddly.

Most things you'd think of as tools of the trade count as plant and machinery: computers, printers, machinery, office furniture, tools, signage and commercial vehicles. There are exceptions — cars have their own rules, which we'll come to — and you can't claim for anything bought purely for personal use. Items you lease rather than buy usually fall under different rules altogether, so check before you assume.

The Annual Investment Allowance is your first stop

The Annual Investment Allowance (AIA) is the big one. It currently sits at £1 million per business per year, and it lets you deduct the full cost of most qualifying plant and machinery from your profits in the year you buy it. Spend £30,000 on equipment and, assuming you're eligible, that's £30,000 off your taxable profit straight away. For most small and medium-sized businesses, the AIA covers everything you're likely to buy in a year.

A few practical points:

• It's shared between connected companies, so a group can't claim £1 million each.
• If your accounting period is longer or shorter than 12 months, the allowance is scaled up or down.
• Cars are excluded — you can never claim AIA on a car.
• You can choose which items to claim on, so it's worth allocating the AIA to assets that would otherwise fall into the 6% special rate pool rather than the 18% main pool, because that gives you the bigger benefit.

Limited companies also have full expensing, which gives 100% relief on main rate plant and machinery and 50% on special rate assets. It's more generous than the AIA in some respects because there's no £1 million ceiling, but it's only open to companies, not sole traders or partnerships. If you run a company and buy a lot of kit, it's worth asking your accountant which route suits you best.

Pooling: the 18% and 6% regimes

Anything you don't write off in full goes into a pool, and each pool is written down at a set percentage on a reducing balance basis. That means you get a tax deduction each year on the remaining value, not the original cost.

• Main pool — 18%. Most plant and machinery, including vans, computers and general equipment.
• Special rate pool — 6%. Integral features (air conditioning, electrical and lighting systems), long-life assets, and cars with higher emissions.

Reducing balance means the relief stretches over many years, so a £10,000 asset in the main pool gives you £1,800 in year one, then 18% of £8,200 the next, and so on. There's a handy small pools allowance: if the unrelieved balance across your pools is £1,000 or less, you can write the whole lot off in one go. It's a small but welcome simplification.

Cars, vans and commercial vehicles

Vehicles trip people up more than anything else. Here's the short version:

• Vans and commercial vehicles (including pickups, lorries and motorcycles) qualify for the AIA, so you can usually claim the full cost in year one.
• New zero-emission cars attract a 100% first-year allowance, which is a genuinely valuable relief while it remains available.
• Other cars go into a pool depending on CO2 emissions: those at 110g/km or below sit in the 18% main pool, and those above that go into the 6% special rate pool. You never get AIA on a car.

If you use a vehicle privately as well as for business, you'll need to restrict your claim to the business proportion. Keep mileage records — they're your evidence if HMRC ever asks.

Selling, scrapping and part-exchange

When you dispose of an asset, the proceeds don't usually produce a separate tax bill or refund. Instead, the sale value is deducted from the pool it belongs to. If that leaves a positive pool balance, you carry on claiming writing down allowances on the reduced figure. If the proceeds exceed the pool balance, the pool goes negative and that excess becomes a balancing charge — taxable income. Note that you can only deduct sale proceeds up to the original cost of the asset; anything above that is a capital gain, not a balancing charge.

If you sell an asset you claimed the AIA on in an earlier year, the proceeds still go into the pool, which can create a balancing charge. It isn't a penalty, just the relief catching up. Track disposals carefully so you don't get a surprise.

Records and planning that pay off

Good capital allowances claims rest on good records. Keep invoices for every purchase, note the date the asset was brought into use (that's what triggers the claim, not the order date), and log disposals with their sale value. If you're near a year end and considering a big purchase, timing matters: claiming in a year when you have plenty of profit is more valuable than claiming in a loss-making year, where allowances may only increase a carried-forward loss. And do check whether a repair is a repair — fixing something is usually a revenue expense you can deduct in full, while improving or upgrading it is capital.

Capital allowances reward the businesses that plan ahead rather than the ones rummaging for receipts in January. Get the basics right and the relief does a lot of the work for you.