Capital Gains Tax calculator

Your gain doesn't get its own tax band — it stacks on top of your other taxable income for the year. Whatever's left of your basic-rate band (£37,700 wide) after your other income is used is taxed at 18%; the rest is taxed at 24%. The more other income you have, the more of your gain lands in the 24% portion.

Yes. It's been cut sharply: £12,300 in 2022/23, down to £6,000 in 2023/24, then £3,000 from 2024/25 onward, where it's stayed frozen since. It used to shelter meaningful gains; now it barely dents a typical property or share sale.

Usually not — Private Residence Relief exempts your only or main home from CGT entirely in most cases. This calculator is for everything else: a second home, a buy-to-let property, shares, funds, or other chargeable assets. If you're not sure your relief applies in full (e.g. you let out part of the property, or it wasn't your main home the whole time you owned it), get specific advice.

For UK residential property that isn't your main home, you must report the gain and pay the tax within 60 days of completion, using a separate 'Capital Gains Tax on UK property' return — not just wait for your normal Self Assessment deadline. Missing it can trigger penalties even if you'd have owed the same amount either way.

Yes, since 30 October 2024. Before that, shares and other non-property assets were taxed at lower rates (10%/20%) than residential property (18%/24%). The Autumn 2024 Budget aligned them, so this calculator applies the same 18%/24% rates regardless of asset type.

Costs directly tied to buying, improving, or selling the asset — legal fees, estate agent or broker fees, Stamp Duty paid on the original purchase, and the cost of capital improvements (an extension, not routine repairs or redecoration). Mortgage interest and normal running costs don't count.

Losses from the same tax year as this gain must be set against it in full — you can't choose to save them for later. Losses brought forward from earlier years (reported to HMRC at the time) are more flexible in reality — you can use only as much as needed to avoid wasting your Annual Exempt Amount, carrying the rest forward again. This calculator applies both in full for simplicity, which is a reasonable estimate but not always the most tax-efficient use of brought-forward losses.

This calculator assumes the asset itself made a gain — if the sale itself was a loss, there's no tax due, and that loss can potentially be offset against other gains you made this year or carried forward to offset future gains once reported to HMRC. The 'losses' fields above are for offsetting losses made on other assets against this gain, not for the case where this specific sale was itself a loss.

No — treat it as a planning estimate. It applies losses in a simplified way (see above), and doesn't model Business Asset Disposal Relief, Private Residence Relief edge cases, or gains you've already made elsewhere this tax year beyond the simple exempt-amount toggle above. Always confirm final figures with an accountant, HMRC's own tools, or your Self Assessment software before filing.