Calculator · 3 min

Capital gains tax on UK property

Residential property is taxed at 18% within the basic-rate band and 24% above it. The annual exempt amount is £3,000. Spousal ownership, documented improvements, and private residence relief can each materially change the figure.

Property

Purchase price (£)What you originally paid for the property.Purchase costs (£)SDLT paid, legal fees, survey, mortgage arrangement — deductible from the gain.Capital improvements (£)Extensions, loft conversions, structural work. Not redecoration or ongoing maintenance.Sale price (£)Selling costs (£)Estate agent, legal fees — deductible from the gain.

Ownership

How is the property owned?

Sole ownershipJoint with spouse, 50/50Joint with spouse, custom split

Tax bands

Your tax band for 2025/26

Basic rate (income ≤ £50,270)Higher or additional rate

Spouse's unused basic-rate band (£) — for comparisonWe'll show how much you could save by transferring a share of beneficial interest to a basic-rate spouse before sale.

Spouse's current band

Basic rateHigher rate

Private residence relief (optional)

I lived in this property as my main residence for part of the ownership period.

Your CGT — 2025/26

Base cost£429,500

Gross gain£272,500

Taxable (after £3k AEA)£269,500

CGT payable£64,680

Effective rate on gain23.7%

Spousal rebalancing saving

£2,040

Transferring 50% of the beneficial interest to your spouse before exchange — via a Deed of Assignment — would reduce your household CGT by this amount. Setup cost is typically £600–£900. Must be executed before exchange, not after.

60-day reporting: UK residents must report and pay CGT on residential property within 60 days of completion via HMRC's online service.

Match me with a CGT specialist

Notes on the calculation

Base cost includes purchase costs and capital improvements. SDLT paid on purchase, legal fees, survey, and mortgage arrangement all reduce the taxable gain. Capital improvements — extensions, loft conversions, structural work — also reduce it; redecoration and repairs do not. Harrow Council Building Control records often recover improvement evidence for properties held 15 years or more.

The 60-day reporting deadline applies to UK residents where tax is due. Non-residents must file an NRCGT return on every disposal of UK residential property regardless of gain or loss — different rules.

Spousal rebalancing must happen before exchange, not after. HMRC's position is that beneficial interest for CGT purposes cannot be backdated to save tax retrospectively. A Deed of Assignment transferring ownership to a spouse takes a few days to execute but must precede the exchange of contracts.

Private residence relief is a nuanced area. This calculator applies a simple ratio of occupation period to total ownership plus the automatic final-9-months rule. In practice, PRR can be affected by shared occupation, periods of qualifying absence, and mixed-use periods — a specialist review often changes the relief figure.

Ready for a proper review?

A specialist can identify reliefs the calculator doesn't surface.

PRR on mixed-use periods, lettings relief in narrow post-2020 circumstances, improvement base cost reconstruction from council records, and pre-exchange spousal restructuring are all areas where generalist accountants miss opportunities. The diagnostic quiz matches you with a specialist in 48 hours, free of charge.

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