GlossaryTax
What is form CT600?
Form CT600 is the company tax return a UK company files with HMRC to report its Corporation Tax position for an accounting period. It is submitted together with the company's statutory accounts and a tax computation showing how the taxable profit was derived.
In practice, in the UK
The CT600 itself is a structured form rather than a narrative document: it captures the figures — taxable profit, reliefs claimed, tax due — while the supporting computation shows the workings behind them and the statutory accounts provide the underlying financial position. All three normally travel together to HMRC as a single submission, and the accounts within that submission must be tagged in iXBRL format rather than filed as a plain document. A company’s first CT600 after incorporation is often where accounting periods and Corporation Tax periods first diverge, since a long first period of trading can need splitting into more than one CT600.
In Odoo
Odoo is not where a CT600 gets prepared, since the form and its computation sit within specialist tax software or an accountant’s toolset rather than an ERP’s ledger. Odoo’s role is upstream: producing accounts that reconcile cleanly and a trial balance that maps sensibly onto the computation, so that whoever prepares the CT600 is not first reconstructing the numbers from scratch.
Common mistakes
- Treating the CT600 as a copy of the accounting profit rather than a separately computed tax figure.
- Missing that a long first trading period may need to be split across more than one CT600.
- Filing accounts that are not properly tagged for the submission, delaying acceptance by HMRC.
These definitions are for guidance and do not replace professional advice. Each entry carries its last-updated date. Filing deadlines are not listed here: they change every year.