What Does a Corporation Tax Accountant Do?

If you run a limited company, Corporation Tax is one of your main obligations. A Corporation Tax accountant makes sure it is calculated correctly, filed on time, and no higher than it needs to be. Here is what that involves.

Preparing the computation

Your taxable profit is not simply your accounting profit. Adjustments are needed, for example, disallowing certain expenses and applying capital allowances. The accountant prepares a correct Corporation Tax computation from your accounts.

Filing the CT600 return

The company’s Corporation Tax return (the CT600) must be filed with HMRC, usually within 12 months of the accounting period end, with the tax itself normally due 9 months and 1 day after the period end. Your accountant prepares and submits the return and flags the payment dates.

Claiming reliefs and allowances

This is where good advice earns its keep. Capital allowances, the Annual Investment Allowance, loss reliefs and, where genuinely applicable, R&D relief can all reduce the bill. A Corporation Tax accountant identifies what your company can legitimately claim.

Planning ahead

Beyond compliance, they help you plan: timing investment, structuring director pay, and making decisions with the tax impact in mind before the year closes rather than after.

Keeping you compliant

They keep you on the right side of the rules and the deadlines, with records that stand up to scrutiny. Explore our Corporation Tax service or our support for limited companies.

Figures and rules are correct to the best of our knowledge as of October 2026 and relate to the 2026/27 tax year unless stated. Tax rules change and depend on your circumstances, always check current guidance on GOV.UK or speak to us before acting.