Corporation tax: the payment dates UK small companies get wrong
Corporation tax is one of the few taxes where the two most important dates are different, and that difference catches small companies out every year. The payment deadline and the filing deadline fall months apart, and treating them as the same date is how interest charges and penalties start. Here are the dates that matter, and the mistakes that turn them into money lost. 1. The payment deadline: 9 months and 1 day after year end For most small companies, corporation tax is due 9 months and 1 day after the end of the accounting period. A company with a 31 December year end pays its corporation tax by 1 October the following year. A company with a 31 March year end pays by 1 January. This is a single payment of the full amount. There are no instalments for a small company, and no reminder that feels urgent until the date is close. The practical step is to diary the date at the same time the year end is closed, not when the accounts are nearly finished. If the accounts are prepared i...