BIM81000 - Computation of liability: contents

NOTE: The basis period rules are changing in 2023/24, which may mean that the guidance in these pages may not apply from the tax year 2023/24 (depending on your circumstances. Please see BIM81230 to BIM81360 for guidance on the transitional year in 2023/24 and BIM81201 for 2024/25 onward.

This chapter explains how profits chargeable to Income Tax are computed. Profits are calculated with reference to a period of account which may not correspond with a tax year. There are rules to determine which period or periods will form the basis for the charge to tax for a particular year. The legislation on basis periods is in S196-S220 Income (Trading and Other Income) Act 2005.

1. BIM81001

   Introduction to basis periods
2. BIM81010

   Basis periods – general rules
3. BIM81015

   Commencement years
4. BIM81020

   First accounting date just before end of tax year
5. BIM81025

   Year of cessation
6. BIM81030

   Slight variations in accounting date
7. BIM81035

   Change of accounting date – introduction
8. BIM81040

   Change of accounting date – years 1 – 3
9. BIM81045

   Change of accounting date – year 4 onwards
10. BIM81050

    Change of accounting date – year 4 onwards - commercial reasons for change
11. BIM81055

    Change of accounting date – year 4 onwards – year after ineffective change
12. BIM81060

    Change of accounting date – year 4 onwards – examples
13. BIM81065

    Apportioning profits to basis periods
14. BIM81070

    Apportioning losses to basis periods
15. BIM81075

    Overlap relief – introduction
16. BIM81080

    Overlap relief – computation
17. BIM81085

    Overlap relief – how given
18. BIM81090

    Overlap relief – given on change of accounting date
19. BIM81095

    Overlap relief – given on cessation
20. BIM81100

    Introduction to `previous year’ basis period rules
21. BIM81105

    Previous year basis – 1996-1997 transitional rules
22. BIM81110

    Previous year basis - transitional overlap relief
23. BIM81200

    Tax Year basis and transitional rules: contents