Calculation methodology
Our calculator applies the statutory rules step by step, entirely in your browser. Here is every step and its source.
Updated for the 2026/27 tax year · Reviewed against HMRC guidance
1. Gain
Disposal proceeds less acquisition cost (TCGA 1992 s.38(1)(a)), incidental costs of acquisition and disposal (s.38(1)(a),(c), s.38(2)) and enhancement expenditure reflected in the asset (s.38(1)(b)).
2. Private Residence Relief
Relief fraction = (actual occupation + final 9 months, capped at ownership) ÷ total months (ss.222–223; HMRC HS283). Other deemed absences under s.223(3) are not modelled and should be added to occupied months if they apply.
3. Ownership split
In joint mode the chargeable gain is split 50/50 (s.60 / beneficial ownership). Each owner receives a £3,000 annual exempt amount (s.1K) and losses entered are divided equally.
4. Rates
Taxable income = gross income less the personal allowance (tapered by £1 for every £2 over £100,000). The unused part of the £37,700 basic rate band is charged at 18%, the excess at 24% (s.1H).
5. Deadline
Return and payment date = completion date + 60 days (Finance Act 2019 Sch.2).
Limitations
The tool does not model non-residents, trusts, companies, part-disposals, rebasing, or Gift Aid/pension band extensions.
Frequently asked questions
This guide is general information based on the Taxation of Chargeable Gains Act 1992 and HMRC guidance (including HS283). It is not personal tax advice — for complex cases speak to a qualified tax adviser.