Corporation tax is charged on the taxable profits of your UK limited company. This includes trading profits, investment income, and chargeable capital gains.
Every active company must submit a CT600 return to HMRC annually and pay any tax due within the strict statutory deadline. Late filing or inaccurate calculations result in automatic financial penalties and interest charges. As a regulated Authorised Corporate Service Provider, we file on your behalf with full ECCTA identity verification built in.
Accurate digital bookkeeping and reconciled year-end accounts are the basis of any correct Corporation Tax calculation. The starting point is the same every year: the numbers have to be right before the planning is worth anything.
Three things now drive most Corporation Tax bills: the 25% rate and Marginal Relief band, Full Expensing on plant and machinery, and Section 455 on overdrawn director loans. If you only look at these once a year after the accounts are done, you miss the easy moves.
With the main rate at 25% and the small profits rate at 19%, profits between £50,000 and £250,000 sit inside the Marginal Relief band, where the effective marginal rate on each additional pound of profit reaches 26.5%.
If you're approaching the edge of the band, we time a purchase or pension contribution to keep you in the lower rate.
Capital purchases are timed and claimed against the right relief. Full Expensing is now permanent and gives 100% relief in the year of purchase on qualifying new plant, machinery and IT. Where Full Expensing does not apply, the Annual Investment Allowance still gives 100% relief up to the £1m cap. See our capital allowances guide for the full breakdown.
Your Director's Loan Account (DLA) is tracked through the year, not reconstructed at year-end. An overdrawn DLA on the accounting reference date triggers a 33.75% Section 455 charge. We flag the position with time to clear it down or formalise the loan, instead of reporting the charge after it has already crystallised.
Six things we cover for every company. The detail changes depending on the business, but the list does not.
CT600 and supporting computations prepared accurately and filed on time.
Advance liability estimates provided during the year so you know what is due well ahead of the payment date.
A line-by-line review of legitimate business deductions, so the figure that lands in the CT600 reflects what the company is entitled to claim, not a cautious approximation.
Salary, dividend and pension contributions modelled together, so what comes out of the company costs the right amount of Corporation Tax going out and the right amount of personal tax coming in.
For holding companies and subsidiaries, we work through the group-relief claims so losses in one entity offset profits in another inside the same accounting period rather than being stranded.
If HMRC opens an enquiry or compliance check, the correspondence comes to us first. We respond on your behalf and only loop you in for the points where your input is genuinely needed.
Missing either of these triggers automatic penalties that escalate with daily and percentage charges. Every CT600 window is tracked in our practice management system, with the return prepared and reviewed weeks before payment is due.
After the end of the accounting period. Companies with profits over £1.5 million pay in quarterly instalments instead.
After the end of the accounting period to file the formal Corporation Tax return. Because payment falls at 9 months, the return goes in well before the final deadline.
For the majority of UK limited companies (those with taxable profits under £1.5 million), corporation tax is payable nine months and one day after your accounting period ends.
The CT600 is the official, statutory corporation tax return submitted to HMRC. It comprehensively details your company's taxable trading profits, allowable deductions, capital allowances, and calculates your final tax liability for the year.
Yes. By claiming all your allowable expenses, using Capital Allowances (Full Expensing or the Annual Investment Allowance), and planning salary, dividends and pensions together, you can legally reduce your Corporation Tax bill.
Corporation Tax modelling through the year so the bill is known before it falls due.
ServiceRegular reporting that keeps your tax position current through the year.
GuideHow the 26.5% effective rate between £50k and £250k works, with worked examples.
Speak with a Chartered Management Accountant about Corporation Tax planning, liability forecasting, and the current numbers available through our management accounts service.
Book a tax consultationCorporation tax for UK limited companies in South Yorkshire, the East Midlands and across the UK, with the work run through secure cloud records and scheduled calls.
