Capital Gains Tax applies when individuals sell, give away, or otherwise dispose of property that has increased in value, with the tax charged on the taxable gain rather than the full selling price. According to HMRC, the calculation involves the disposal value minus acquisition cost, qualifying expenditure, available reliefs and allowable capital losses. For the 2026-2027 tax year, the individual annual exempt amount is £3,000, which applies to qualifying net gains across the tax year rather than separately to every property sold. The current Capital Gains Tax rates are 18% and 24%, depending on taxable income and the remaining basic-rate band. A basic-rate taxpayer does not automatically pay 18% on the entire taxable gain - taxable income and gains are combined, with the part falling within the unused basic-rate band charged at 18% and the remainder charged at 24%. Higher-rate and additional-rate taxpayers will generally pay 24% on taxable property gains.
The taxable gain is calculated as the disposal value minus the acquisition cost, qualifying expenditure, available reliefs and allowable capital losses. As reported by HMRC, qualifying incidental costs of buying and selling, including certain estate agency and legal fees, can normally reduce the gain, provided the expenditure is directly connected with the acquisition or disposal and supported by records. Mortgage interest is not normally an allowable deduction when calculating a property's capital gain, as its treatment for rental income is a separate issue. The calculation can be summarised as the disposal value, less the acquisition cost, less qualifying buying and selling costs, less qualifying capital improvements, less available reliefs and allowable losses. Any remaining net gains are then considered against the individual's annual exempt amount before the relevant tax rate is calculated. For an investor with years of ownership, incomplete paperwork can be expensive - completion statements, invoices, contracts, Stamp Duty Land Tax records and evidence of improvement works should be assembled before the property is marketed rather than after completion.
Private Residence Relief may protect qualifying periods during which the property was the owner's only or main residence, with the final nine months of ownership normally covered in many cases. According to HMRC, relief is calculated by reference to qualifying periods rather than treating the entire gain as automatically exempt or taxable. For landlords relying on past occupation, council tax records, electoral records, correspondence and utility bills may help demonstrate actual residence. Letting Relief is now much narrower than many landlords expect, generally applying only where the owner shared occupancy with the tenant, subject to detailed statutory conditions. The factual pattern of residence, including letting, absences, business use and partial occupation, can affect the amount of relief available. Relief may cover qualifying periods of occupation, and in many cases, the final nine months of ownership. The remaining part of the gain may still be taxable, so the complete ownership history matters for accurate calculation.
Capital Gains Tax due on UK residential property must normally be reported and paid within 60 days of completion. As reported by HMRC, a Self Assessment disclosure may also be required even where a 60-day property return has already been submitted. For jointly owned properties, each beneficial owner normally calculates and reports their own share of the gain, with ownership percentages, allowable costs, losses, reliefs and annual exempt amounts not transferring automatically between owners. Allowable capital losses can reduce taxable gains, with HMRC permitting a capital loss to be claimed up to four years after the end of the tax year in which the disposal occurred, although the correct treatment depends on the asset and circumstances. For a portfolio landlord, timing several disposals within one tax year can materially affect the combined calculation, justifying modelling gains, losses, finance costs and commercial objectives before accepting offers. A qualified accountant or tax adviser should model the complete position before a company property is sold or transferred, as two layers of tax can arise when sale proceeds are later extracted from the company.
