The Corporation Tax is the UK’s company income tax: the tax your business pays on its profits. It is one of the core tax obligations for any UK Ltd and is managed through HMRC (the British tax authority).
What is it calculated on?
Corporation Tax is calculated on your company’s profits: revenue minus deductible expenses. It is not paid on gross turnover, but on actual profit after costs.
What is the tax rate?
The rate depends on your company’s profit level. The United Kingdom applies a reduced rate for smaller profits and a higher standard rate for larger profits, with an intermediate band. The exact rates are set by HMRC and can vary each tax year — consult with your advisor about the rate applicable to your situation.
Key deadlines
- Tax payment: normally 9 months and 1 day after your accounting year-end
- Return submission (CT600): 12 months after the end of your accounting period
It is important to note that the payment date comes before the submission date — you must pay before filing your formal return.
Do I need to register?
Every active company must register for Corporation Tax with HMRC following incorporation. You will receive a UTR (Unique Taxpayer Reference), your tax identifier with HMRC, which will appear in your Documents section.
How does Aiden help?
Aiden displays your Corporation Tax key dates in the Taxes section and sends you reminders. For the calculation and submission of your CT600 return, we recommend working with an accountant or, on the PRO plan, with your personal advisor.