Capital Gains Tax calculator
Inputs can include asset type, purchase price, sale price, buying and selling costs, qualifying improvements, other taxable income and available capital losses.
1. When can CGT apply?
Common disposals include shares held outside ISAs, second homes, buy-to-let property, business assets, land, cryptoassets and valuable personal possessions.
A main home may qualify for Private Residence Relief, but full relief should not be assumed where there have been periods of letting, business use or other complicating facts.
Not sure if your disposal falls within these rules?
Estimate my CGT2. How a capital gain is calculated
Start with disposal proceeds, then deduct allowable acquisition cost and qualifying incidental costs. Certain capital improvement expenditure may also qualify if the statutory conditions are met.
Example: £100,000 sale proceeds less £65,000 purchase cost and £5,000 allowable buying/selling costs gives a £30,000 gain before reliefs. After a £3,000 Annual Exempt Amount, the taxable gain would be £27,000.
3. Capital losses
Allowable capital losses are generally set against gains. Unused losses may usually be carried forward once properly notified to HMRC, subject to time limits and the detailed rules.
Loss planning matters because the annual exemption and brought-forward losses interact differently depending on the year and gains available.
4. Transfers between spouses and civil partners
Transfers between spouses and civil partners living together are normally made on a no-gain/no-loss basis.
That can be relevant before a disposal, but ownership, anti-avoidance rules and non-tax commercial considerations should be reviewed rather than treating it as a mechanical tax exercise.
5. Reporting Capital Gains Tax
Many gains are reported through Self Assessment. UK residential property disposals that create CGT can also trigger a separate 60-day reporting and payment requirement from completion.
Missing the property deadline can lead to penalties and interest even where the gain is also reported later on a tax return.
Worried about missing the 60-day property deadline?
Estimate my CGT6. Reliefs that may reduce a gain
Depending on the asset and facts, possible reliefs include Private Residence Relief, Business Asset Disposal Relief, rollover relief, hold-over relief and other specialist reliefs.
Relief should never be assumed solely because the asset is a home, a business interest or an investment — each relief has its own conditions.
Not sure which reliefs you qualify for?
Estimate my CGT7. Common CGT mistakes
The most common errors are using sale proceeds instead of the gain, missing acquisition or disposal costs, treating repairs as capital improvements, ignoring share matching rules and missing the 60-day property deadline.
The £3,000 Annual Exempt Amount applies per individual per tax year, not separately to every asset sold.
Frequently asked questions
Is CGT charged on the whole sale price?
No. CGT is generally charged on the taxable gain after allowable costs, losses, exemptions and reliefs.
What are the main CGT rates in 2026/27?
For most gains, 18% applies to the extent taxable gains fall within the unused basic-rate band and 24% above it.
Can capital losses be carried forward?
Often yes, once properly notified to HMRC and subject to the applicable rules and time limits.
Do I have to report a property gain within 60 days?
Where CGT is due on a UK residential property disposal, a separate 60-day reporting and payment obligation can apply.
Selling property, shares or another asset?
Use a CGT estimate as a starting point, then check the disposal facts, available losses and reliefs before filing.
Estimate my CGTThis guide provides general information only and does not constitute personal tax or financial advice. Tax treatment depends on individual circumstances.