Capital Gains Tax Calculator UK

Capital Gains Tax (CGT) is charged on the profit you make when you dispose of an asset that has increased in value. A disposal includes selling an asset, gifting it, swapping it for something else, or receiving compensation for it — such as an insurance payout. The tax is not levied on the full sale proceeds but on the gain: the difference between what you received and what you originally paid, after deducting any allowable costs.

This calculator works by first determining your total gain — sale proceeds minus the original purchase price and any allowable costs. Allowable costs include solicitor and estate agent fees on purchase and sale, the cost of improvements to the asset (but not maintenance or repairs), and any incidental costs of acquisition. Once the gross gain is established, the Annual Exempt Amount of £3,000 is subtracted. Any gain up to £3,000 per tax year is entirely free of CGT, so only the amount above this threshold is taxable.

Your income level determines which CGT rate applies to your taxable gain. If your total income for the year plus your taxable capital gain stays within the basic-rate income tax band (£50,270 for 2025/26), the portion within that band is taxed at 18%. Any portion of the gain that pushes your total above £50,270 is taxed at 24%. If your income already exceeds £50,270 before the gain, the entire taxable gain is charged at 24%.

Business Asset Disposal Relief (BADR), formerly known as Entrepreneurs' Relief, provides a reduced flat CGT rate of 14% for qualifying business disposals in 2025/26, rising to 18% from April 2026. The lifetime limit is £1 million of qualifying gains. BADR applies to disposals of all or part of a trading business, shares in a personal company, or assets used in a business that is being wound down.

The results show every stage of the CGT calculation so you can understand exactly where the tax liability comes from. The total gain is your headline profit before any relief. The Annual Exempt Amount of £3,000 is then deducted, leaving the taxable gain on which CGT is actually calculated. The CGT due figure is the tax you would owe if you disposed of the asset in the current tax year with no other CGT disposals.

You may owe nothing at all if your total gain — across all disposals in the same tax year — is £3,000 or less, since it falls entirely within the Annual Exempt Amount. You may also owe little or nothing if you are a basic-rate taxpayer with substantial remaining band: a gain that sits wholly within the unused basic-rate band is taxed at only 18%, and if your income is low enough the Annual Exempt Amount may absorb the entire taxable gain.

There are several legitimate strategies to reduce your CGT liability. Transferring assets to a spouse or civil partner before disposal is one of the most effective: the transfer itself is CGT-free, and your partner can then use their own Annual Exempt Amount and basic-rate band. Selling assets in tranches across different tax years allows you to use the Annual Exempt Amount each year. "Bed and ISA" — selling holdings outside an ISA and immediately repurchasing them inside — shelters future growth, though you crystallise a gain at the point of sale. Tax-loss harvesting involves deliberately selling loss-making assets in the same tax year to set losses against gains. For BADR-qualifying assets, timing the disposal carefully in relation to income in the same year can maximise the benefit of the 14% rate before it rises to 18%.

For assets other than residential property, CGT is reported via Self Assessment and payment is due by 31 January following the end of the tax year in which the disposal took place. For the 2025/26 tax year, the payment deadline is 31 January 2027.