Corporation Tax Basics for UK Company Directors

A limited company pays corporation tax on its profits, separately from anything the owner pays personally. Directors of small companies frequently misunderstand what is taxed and when it is payable, and both errors are expensive. This sits alongside reading your company accounts as core financial knowledge for running a company.

What Is Actually Taxed

Tax is charged on taxable profits: trading profits, plus investment income and gains on disposals. Taxable profit is not the same as the profit in your accounts, because some costs are not deductible for tax and some allowances apply that accounts do not reflect.

Rates and Thresholds Change

Rates, thresholds and the treatment of smaller companies are set by government and revised at fiscal events. Any figure quoted in an article dates quickly, so confirm current rates with HM Revenue & Customs before relying on them for planning.

The Payment Deadline Comes Before the Filing Deadline

This is the detail that catches directors out. Corporation tax is generally payable some months after the end of the accounting period, while the tax return itself is due later still. Waiting until the return is prepared to think about paying means the money is already overdue.

Provide for it monthly as profits arise rather than facing it as a lump sum. A cash flow forecasting forecast should carry the payment on its due date from the start of the year.

Disallowable Costs

Client entertaining is the classic example — a legitimate business cost that is not deductible for tax. Others include certain penalties and some legal fees. Your accounts and your tax computation will therefore differ, which is normal and not an error.

Capital Allowances

Equipment and other capital purchases are not deducted as ordinary expenses; instead, capital allowances give relief, often generously in the year of purchase. Timing a significant purchase either side of a year end can affect when relief is available, which is worth a conversation with your accountant before buying.

Research and Development Relief

Companies undertaking qualifying research and development may claim enhanced relief. The definition of qualifying activity is narrower than most directors assume, and claims must be supported by contemporaneous records of what work was done and why it was uncertain. Take advice from someone who handles these regularly.

Losses Are Not Wasted

A company making a loss can generally carry it forward against future profits, and in some circumstances back against earlier ones. This matters for a business investing ahead of revenue, because early losses reduce later tax. It requires the losses to be properly recorded and returned.

Salary, Dividends and the Director’s Loan Account

How you extract money affects the overall tax cost across the company and you personally. Drawing informally through the year creates a director’s loan account, and an overdrawn balance at the year end can trigger a separate charge. Deciding the mix deliberately, with advice, is more efficient than taking money ad hoc and reconciling later.

Accounting Periods and Long First Years

Corporation tax is charged by accounting period, which cannot exceed twelve months. A first year running longer than that is split into two periods with two returns, each with its own deadlines. New directors are frequently caught out by this.

Associated Companies Can Change the Rate

Where the same people control more than one company, the companies may be treated as associated, which can affect which rate applies and the thresholds available. If you run several companies, this is worth checking rather than assuming each is assessed in isolation.

Interest and Penalties Are Separate

Paying late attracts interest; filing late attracts penalties. They are distinct, which means filing on time while arranging to pay is materially better than doing neither. If cash is short, file and then talk to HMRC about the payment.

Dividends Must Come From Profits

A company can only pay dividends out of distributable profits, evidenced by accounts. Paying dividends the company has not earned creates an unlawful distribution, which is usually reclassified as a loan and taxed accordingly. Check the position before drawing rather than after the year end.

Trading and Non-Trading Income Differ

Profits from your trade, rental income from property the company owns, and gains on selling assets are treated differently within the computation. A company doing more than one thing needs its income identified correctly rather than lumped together, because the treatment and the available reliefs are not the same.

Plan Around the Year End Deliberately

Timing of equipment purchases, pension contributions and bonuses can affect which period they fall into and when relief arises. A short conversation with your accountant a month before the year end is worth considerably more than the same conversation two months after it.

Filing and Paying Are Separate Actions

Submitting the return does not pay the tax, and paying does not file the return. Both have their own deadlines and their own consequences for being late. Directors occasionally do one and assume the other followed automatically.

Claiming Expenses Correctly

A cost is deductible if incurred wholly and exclusively for the trade. Where there is a private element, only the business proportion qualifies, and you need a defensible basis for the split. Directors treating company money as a personal account create both a tax problem and an accounting one.

Group Structures Add Complexity

Holding companies, subsidiaries and transactions between related companies all bring additional rules on how profits and transfers are treated. If you are considering more than one company, take advice on the structure before creating it.

Keep Evidence for Anything Unusual

Larger or non-routine items — a significant asset purchase, a substantial repair, a payment to a connected party — are the ones most likely to be questioned. Keeping the invoice and a short note of the business reason at the time is far easier than reconstructing the justification two years later.

Keep the Records the Return Depends On

Tax computations are built from bookkeeping. Accurate, current records make the return straightforward and the fee smaller; poor records make it slow, expensive and more likely to be wrong. Filing on time also protects your business credit profile, since late filings are visible on the public record.