Capital Gains Tax when you sell a property
Tax is charged on the gain, not the sale price, and Private Residence Relief removes the proportion of that gain covering the period you lived there — plus the final nine months of ownership regardless.
Figures stated for the 2026/27 UK tax year. Content last checked against official sources on .
What this calculator does
- Works out the chargeable gain after purchase price, buying, selling and improvement costs.
- Applies Private Residence Relief for the period the property was your main home.
- Splits the taxable gain across the 18% and 24% rates.
- Reports the 60-day reporting and payment deadline.
How the calculation works
The starting point is the gross gain: the sale price less what you paid, less the costs of buying and selling and any capital improvements. Repairs and maintenance do not count — only genuine enhancements. Private Residence Relief then removes the proportion of that gain matching the period the property was your only or main residence, and the final nine months of ownership always qualify regardless of how the property was used in that time. So a property owned for 120 months and lived in for 36 gets relief on 45 of those months, not 36. The annual exempt amount of £3,000 is deducted from what remains. The taxable gain is then stacked on top of your income for the year: the part that still fits inside the basic rate band is charged at 18%, and everything above at 24%. Because the gain sits on top of income, a large gain will nearly always spill into the higher rate even for a basic rate taxpayer.
The rule
Taxable gain = (sale price − purchase price − buying, selling and improvement costs) × (1 − relieved months ÷ months owned) − £3,000. Tax = 18% on the part within the basic rate band, 24% above.
Step by step
- Deduct the purchase price and all allowable costs from the sale price to give the gross gain.
- Add nine months to the period lived in as a main residence, and relieve that proportion of the gain.
- Deduct any capital losses brought forward.
- Deduct the £3,000 annual exempt amount.
- Stack the remaining gain on top of your income and charge 18% within the basic rate band and 24% above.
Worked example
A property bought for £220,000 and sold for £350,000 after ten years, lived in as a main home for the first three, by someone with £35,000 of other income.
What was entered
| Sale / Disposal price | £350,000 |
|---|---|
| Original purchase price | £220,000 |
| Buying costs | £7,500 |
| Selling costs | £4,500 |
| Capital improvements | £15,000 |
| Total ownership period | 120 months |
| Months lived in as your main home | 36 months |
| Other taxable income in tax year | £35,000 |
The arithmetic
- Allowable costs total £7,500 + £4,500 + £15,000 = £27,000.
- The gross gain is £350,000 − £220,000 − £27,000 = £103,000.
- Relief covers the 36 months lived in plus the final 9 months, so 45 of 120 months — 37.5% of the gain, which is £38,625.
- That leaves £64,375, reduced by the £3,000 annual exempt amount to a taxable gain of £61,375.
- With £35,000 of income there is only £2,700 of basic rate band left, taxed at 18%: £486.
- The remaining £58,675 is charged at 24%: £14,082.
- Total Capital Gains Tax is £14,568, and it must be reported and paid within 60 days of completion.
What the calculator returns
| Gross gain | £103,000.00 |
|---|---|
| Private Residence Relief | £38,625.00 |
| Taxable gain | £61,375.00 |
| Tax at 18% | £486.00 |
| Tax at 24% | £14,082.00 |
| Total Capital Gains Tax | £14,568.00 |
| Reporting deadline (days) | 60 |
Key assumptions
- The property was your only or main residence for the months entered, and relief is given on a straight time-apportioned basis.
- The final nine months of ownership qualify for relief regardless of use.
- Improvement costs are genuine capital enhancements rather than repairs or maintenance.
- The gain is stacked on top of the other income entered for the same tax year.
Limitations
- Time apportionment is a simplification. Periods of absence, job-related accommodation and elections between two residences can all extend relief in ways this calculator does not model.
- A longer final period of 36 months applies for disabled people and those moving into a care home.
- Lettings relief, where it still applies, is not modelled.
- Transfers between spouses and civil partners happen at no gain and no loss, which changes the arithmetic substantially and is not covered.
- Where a property is jointly owned, each owner has their own annual exempt amount and their own rate band, so a joint disposal is not simply this figure halved.
- This is an estimate, not a Self Assessment computation, and the 60-day deadline is strict.
Common questions
Do I pay Capital Gains Tax when I sell my own home?
Why do I get relief for nine months I did not live there?
Can I deduct the kitchen I replaced?
How quickly do I have to pay?
We own it jointly — is the tax just halved?
Related calculators
- Capital Gains Tax Calculator — Capital Gains Tax on assets other than property, using the same allowance and rates.
- Buy-to-Let Calculator — Model the letting years before the eventual disposal.
- UK Income Tax Calculator — The income the gain stacks on top of decides how much falls at 24%.
Official sources
Every figure in this guide was checked against the sources below. Where a source could not confirm a figure, it is marked as requiring verification rather than presented as settled.
- Capital Gains Tax: rates — GOV.UK (from 6 April 2026)18% on gains within the basic rate band, 24% above it
- Capital Gains Tax: allowances — GOV.UKAnnual exempt amount £3,000 for individuals
- CG64985: Private residence relief: final period exemption — HMRCThe final 9 months of ownership qualify for relief for disposals on or after 6 April 2020, or 36 months for disabled persons and care home residents
- Tax when you sell your home — GOV.UKConditions for full Private Residence Relief
- Capital Gains Tax for non-residents: UK residential property — GOV.UKResidential property gains must be reported and paid within 60 days of completion where completion was on or after 27 October 2021