To calculate the UK corporation tax for a company, it is necessary to supply the following information:

• The annual taxable profits for the company for the given tax year.
• The financial tax year, noting that this runs from 1 April in the first year to 31 March in the next.
• The number of associated companies.

Some extra points to note about the tool are...

• Before using this tool, the taxable profits that are deemed to be part of the specified financial tax year need to be determined. The tool does not support the extra step of splitting profits into different financial tax years depending on the company's accounting period.
• The tool does not handle calculations for companies with ring fence profits, where ring fence means income and gains from extraction activities or oil rights in the UK and the UK continental shelf.

The data (e.g. rates) used by this tool was obtained primarily from...

http://www.hmrc.gov.uk/rates/corp.htm

Associated tool link: http://www.coggit.com/tools/uk_corporation_tax_calculator.html