What can't my company claim? (disallowable costs)

Updated 27 June 2026
The short answer

Some costs your company pays don't cut its Corporation Tax, even though the money really goes out the door. The usual suspects: taking clients out, most fines, the personal share of anything, dividends you pay yourself, and the price of buying equipment you keep. With most of these the company can still pay, it just doesn't lower the tax. Equipment is the odd one out: it does get relief, only by a different route. We put each cost on the right side for you.

What does "can't claim" actually mean?

It almost never means "the company isn't allowed to pay for it". It means "the company can pay, but that cost won't lower your Corporation Tax". When we work out the tax, a disallowable cost gets added back, so the bill comes out the same as if you'd never spent the money. The money still left the company. It just didn't save you any tax.

One test sits behind all of it: was the cost spent purely to run the business? If part of it was personal, or it was a punishment, or it wasn't really a running cost at all, it usually can't reduce your tax.

The costs that don't cut your tax (the common ones)

Here are the ones people get caught by most often, and a one-line why for each:

  • Taking clients or customers out (entertaining): lunch, drinks, an event, tickets. The company can pay, but it never lowers your Corporation Tax. (A genuine do for your own staff works differently, that one can count.)
  • Most fines and penalties: a parking fine, a speeding fine, a penalty for breaking a rule. These are a punishment, not a running cost, so they don't reduce your tax.
  • The personal share of anything: if a cost is part business and part personal, only the clearly separable business part can count. A fully personal cost can't go in at all.
  • Dividends you pay yourself: these come out of profit after tax, so they were never a cost in the first place. They can't reduce the tax. (A salary paid through payroll is different, that one is a real cost.)
  • The price of buying equipment you keep: a laptop, tools, machinery, a van. The purchase isn't an everyday cost, so it doesn't go in like rent or stock. It still gets relief, just by a different route (more on that below).
  • Depreciation: the figure your accounts use to spread an asset's cost over the years. For tax we add it back and give the equipment relief instead, so the depreciation figure itself doesn't reduce your tax.

Why is client entertaining the one everyone gets wrong?

Because it feels like an obvious business cost, you took a client out to win work, so surely it counts? The company can pay for it, and the money genuinely goes. The catch is that it doesn't reduce your Corporation Tax: we add it back when we work out the tax, so the bill stays exactly the same. People expect this one to save tax, and it doesn't. (Entertaining your own staff, like a team Christmas party, can work differently, that's a separate guide.)

Why doesn't buying a laptop or a van count like other costs?

Because you keep and use it for a long time, it's not an everyday running cost like rent or stock. So it doesn't go in the same way. But it isn't lost, it gets its own kind of relief, and for almost every small company the full cost still comes off your profit, often in the year you buy it, up to a yearly limit of £1 million. So buying equipment usually cuts your tax just as much, it simply goes in a different box. (Cars are the main exception and follow separate rules.)

You might also see the word "depreciation" in your accounts, which is the bit of that cost spread across the years. For tax we add that figure back and use the equipment relief above instead. We handle that swap for you, so you don't lose out.

What about dividends, fines, and a cost that's half personal?

  • Dividends are how you take profit out of the company for yourself. They're paid after the Corporation Tax is worked out, so they can't reduce it, they're not a cost, they're a share of what's left. A salary through payroll is a real cost and does reduce the tax. The right mix of the two depends on your situation.
  • Fines are a punishment for breaking a rule, not a cost of running the business, so a parking or speeding fine, or a penalty, won't cut your tax.
  • A part-personal cost, say a phone you use for work and home, only counts for the business share, and only if you can work out what that share is. The personal slice never counts.

What about charity donations?

Money your company gives to charity can reduce your tax, but it follows its own set of rules rather than going in like a normal business cost, and not every kind of donation qualifies. If your company makes charitable donations, we check whether they reduce your tax and apply the right rule.

How SimpleReturns handles it

Connect your bank or upload a statement, and we sort your costs into the right buckets: the ones that cut your tax come off your profit, and the ones that don't, client entertaining, fines, the personal share, dividends, get added back or kept out so they never wrongly lower your bill. Equipment gets its proper relief. You see every figure before anything is sent, and you never have to work out which side a cost belongs on.


Common questions

If I can't claim it, does that mean the company can't pay for it?

Usually no. With most of these the company can pay, the cost just doesn't reduce your Corporation Tax. We add it back when we work out the tax, so the bill stays the same.

Can I claim taking a client to lunch?

The company can pay for it, but it won't cut your Corporation Tax. Client and customer entertaining is added back when we work out the tax. A genuine do for your own staff can work differently.

Are parking fines or speeding fines tax-deductible?

No. Most fines and penalties are a punishment for breaking a rule, not a running cost, so they don't reduce your tax.

Are dividends a business cost?

No. Dividends come out of profit after tax, so they were never a cost and can't reduce your Corporation Tax. A salary paid through payroll is a real cost.

Why can't I just claim the cost of the laptop I bought?

You can get relief for it, it just goes in differently because you keep and use it. For almost every small company the full cost still comes off your profit, up to a £1 million yearly limit. Cars follow separate rules.

What if a cost is part business and part personal?

You can only count the business share, and only if you can separate it out. A fully personal cost can't be claimed at all.

Ready to do it the easy way?

You don't need to know any of the above to file. We read your year's money in and out, put each cost on the right side of the line, add up what actually cuts your tax, and show you every figure before anything is sent, for £99, once, no subscription.

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Or, if your company has a complicated setup, like a tricky salary and dividend mix or large one-off donations, an accountant may be the better fit, and that's an honest call to make.

General guidance, not advice. This guide explains how the rules generally work for small UK limited companies. It isn't tax advice for your specific situation, if you're unsure, check with us or an accountant.