How this works
UK Capital Gains Tax applies to the profit you make when selling an asset that has gone up in value. The 30 October 2024 Budget realigned the two CGT scales — shares, crypto and other non-residential gains now use the same 18 % / 24 % rates that residential property has used since the pandemic, so there's a single rate table to track instead of two diverging ones. The Annual Exempt Amount (AEA) was cut from £6,000 to £3,000 in April 2024 and stays there — the first £3,000 of total gains across all assets in the tax year is tax-free.
The rate that applies to each slice of your taxable gain depends on where it stacks on top of your taxable income. Use up your basic-rate band first: £37,700 minus your taxable income (income above the personal allowance) gives you the remaining room. Gains within that room are taxed at 18 %; gains above it (or all gains if you're already a higher-rate taxpayer) at 24 %. The widget lets you skip the income calculation by picking "higher / additional rate" if you already know you're above the band — common enough that hiding the income field then is cleaner.
A few things this doesn't model. The sale of your main residence is fully exempt under Private Residence Relief (PRR) — there's no CGT to pay, hence no calculator needed. Business Asset Disposal Relief (BADR, formerly Entrepreneurs' Relief) gives a reduced 14 % rate on lifetime gains up to £1 million from selling a qualifying business — it'll rise to 18 % from April 2026, matching the basic CGT rate at that point. Investors' Relief covers a separate £10M lifetime allowance at 14 %. These reliefs need the right paperwork and qualifying tests, so you should be working with an accountant rather than a calculator.
The formula
AEA: £3,000 (post-April-2024). Basic-rate limit £37,700 is set above whatever Personal Allowance applies (£12,570 for most, tapered above £100k). The 18 / 24 % rates apply equally to shares, crypto and residential property since 30 October 2024. Higher-rate taxpayers (income above ~£50,270 with full PA) pay 24 % on the entire taxable gain.
Example calculation
- Sold shares for a £30,000 gain. Annual income £40,000 (basic rate).
- Taxable gain = 30,000 − 3,000 = £27,000. Basic-room = 37,700 − (40,000 − 12,570) = £10,270.
- 10,270 × 18 % = £1,849 + 16,730 × 24 % = £4,015 → CGT £5,864. Effective rate 19.5 %. Net gain ≈ £24,136.
Frequently asked questions
Did the rates really change overnight in October 2024?
Yes — the Autumn Budget on 30 October 2024 raised the non-residential CGT rates from 10 / 20 % to 18 / 24 % effective immediately. Disposals on or before 29 October 2024 use the old rates; disposals on or after 30 October 2024 use the new ones. The residential-property rates (18 / 24 %) didn't change. This calculator uses the post-30-October rates throughout — for any earlier disposal you'll need a calculator that splits the tax year accordingly.
How do losses interact with the AEA?
Capital losses in the same tax year are netted against gains before the AEA. So if you made a £10,000 gain and a £4,000 loss, your net gain is £6,000, then the £3,000 AEA reduces taxable gain to £3,000. Unused current-year losses go onto your gain pool for future tax years — but they can only be carried forward if you notify HMRC of the loss in your self-assessment, typically within 4 years of the year of the loss. Carried-forward losses are applied after the AEA in the future year, so they don't waste the exemption.
Why isn't my main home included?
Because there's no CGT to pay on it. Private Residence Relief (PRR) fully exempts any gain on the sale of your only or main residence for the period it was your only or main home, plus a 9-month "deemed occupation" extension at the end. If you've never let it out or used part of it exclusively for business, the relief is 100 % and the calculation produces £0. If you have (e.g. a flat you lived in then rented out), the calculation gets more nuanced — you'd apportion the gain by months of qualifying vs. non-qualifying occupation. That's beyond a single-input estimator.