CT600 Tax Return Filing in Cardiff: Prepare and File Your Company Tax Return with HMRC

A CT600 is the form used to submit a Company Tax Return to HMRC. It reports the company's Corporation Tax position for an accounting period, including income, allowable deductions, taxable profit and the resulting Corporation Tax calculation, along with any reliefs or allowances being claimed. It is the formal way a limited company tells HMRC what it owes or, in some circumstances, that no Corporation Tax is due. The CT600 is usually supported by a Corporation Tax computation and by a copy of the statutory accounts, so the figures can be checked against the underlying records.

A company needs to submit a Company Tax Return when HMRC has issued a notice to deliver one, which in practice applies to most active limited companies. A micro-entity company is not exempt simply because it prepares smaller, simplified accounts — the obligation depends on whether HMRC has required a return for that accounting period. Dormant or non-trading companies may be in a different position, and that should be confirmed with HMRC rather than assumed. If you are unsure whether your Cardiff company needs to file, it is worth checking your HMRC correspondence and any notices issued for the period in question.

Yes — they are two separate filing obligations with two separate organisations. The statutory accounts are prepared for the company's members and filed at Companies House, whereas the CT600 is a tax return submitted to HMRC. The accounts provide much of the information used in the tax return, but they are not a substitute for it, and filing accounts at Companies House does not satisfy the Corporation Tax filing requirement. Equally, a CT600 is not a Confirmation Statement or a VAT Return, and none of those other filings can be used in place of the Company Tax Return.

They work together but they are not the same thing. The Corporation Tax computation is the working paper that starts with the accounting profit shown in the accounts and adjusts it to arrive at the taxable profit — adding back disallowable expenses, allowing for capital allowances rather than depreciation, and accounting for items that are not taxable or that attract relief. The CT600 is the return form on which the results of that computation are reported to HMRC. A well-prepared computation gives the CT600 a clear audit trail and makes it easier to answer any questions HMRC might raise.

Taxable profit is arrived at by adjusting the profit reported in the accounts rather than simply repeating it. Typical adjustments include adding back expenditure that is not allowable for tax purposes, such as certain entertaining costs, and deducting capital allowances in place of the depreciation charged in the accounts. Income that is not taxable, and reliefs or losses brought forward, may also need to be reflected. Small and micro companies often assume that because their accounts are simple, the tax calculation will be too, but the adjustments still have to be identified and applied correctly. Because the treatment depends on the company's own transactions, the computation should be built from the actual records rather than from a template.

No — filing and payment are separate obligations. Submitting the CT600 tells HMRC what the company's Corporation Tax position is for the period; it does not transfer any money. If Corporation Tax is payable, the company still needs to make payment through the normal HMRC channels by the relevant due date for its circumstances. It is quite possible to have filed on time and still face interest on an unpaid liability, so it is sensible to plan for both the return and any payment at the same time. Not every company will have a liability — that depends on taxable profits, reliefs and losses.

Yes. Many companies appoint an accountant or tax agent to prepare the computation and CT600 and to submit the return to HMRC on the company's behalf, usually through HMRC's online services once the appropriate authorisation is in place. The company remains responsible for the accuracy of what is filed, which is why it is important to provide complete and reliable records and to review the return before it goes in. Using an agent can be particularly helpful where there are tax adjustments, capital allowances or losses to work through, or where the director simply wants the reassurance of an experienced pair of eyes.

If a Company Tax Return is filed after the statutory filing date, HMRC may charge penalties, and interest or further charges can also arise on any unpaid Corporation Tax. The exact consequences depend on how late the return is and on the company's individual circumstances, so it is not something to estimate in advance. The practical point is that late filing is best avoided: keeping records organised, agreeing the accounts early and preparing the computation promptly all reduce the risk of a scramble at the deadline. If you think a return may be late, it is usually better to speak to an accountant or to HMRC as soon as possible rather than wait.