Overview and time limits

In this lesson

1. 0:00 Corporation tax self-assessment overview
2. 0:27 What is self-assessment and CT 600
3. 0:59 Amendment rights and HMRC determination
4. 2:23 Filing deadlines and XBRL requirements
5. 3:33 Payment deadlines for companies

About this lesson

We'll cover what self-assessment is, how HMRC collects corporation tax through the CT 600 return, and the key deadlines for filing and payment—including the crucial distinction between standard companies (nine months and one day) and large companies (quarterly instalments). Understanding these administrative requirements is vital for both exam success and real-world compliance, so we'll break down the rules clearly so you can apply them with confidence. The lesson explains the core filing obligations: companies must submit their CT 600 return electronically within 12 months of their accounting period end, keep records for six years, and amend returns within 12 months of the statutory filing date. You'll also learn about HMRC determinations—estimates HMRC can issue if no return is filed—and how they're automatically replaced once the actual return is submitted. The payment rules depend on company size, so we'll clarify what makes a company "large" and how that affects when instalments are due.

Duration: 4m