UK Capital Gains Tax Calculator 2025/26
Work out the capital gains tax you owe on shares, property, or other assets — split across the 18% and 24% bands using HMRC 2025/26 rules.
Capital gains tax owed
£3,163.80
- Net gains after losses
- £20,000.00
- Taxable after £3,000 allowance
- £17,000.00
- Gains taxed at 18%
- £15,270.00
- Gains taxed at 24%
- £1,730.00
- Effective rate on net gains
- 15.82%
Based on 2025/26 UK Capital Gains Tax rates. The £3,000 Annual Exempt Amount is deducted from net gains; the remainder is taxed at 18% within your remaining basic-rate band and 24% above it. Business Asset Disposal Relief (14% in 2025/26) and carried interest (32%) are not included — those need a specialist calculation.
How to use this calculator
Enter your total gains for the tax year, any allowable losses you can offset (current-year and brought-forward), and your other taxable income (salary, pension, rental income before tax). The calculator deducts losses, applies the £3,000 Annual Exempt Amount, and splits the remainder across the 18% and 24% bands based on how much of your basic-rate band is left after other income.
How the calculation works
CGT for 2025/26 is charged at 18% within your remaining basic-rate band and 24% above it. Your other income fills the basic-rate band first (£37,700 above the £12,570 personal allowance, i.e. up to £50,270). Whatever band capacity is left is taxed at 18%; gains spilling over are taxed at 24%. The £3,000 Annual Exempt Amount is deducted before any rate is applied.
Worked example
Salary £35,000, gains £20,000, no losses. Other income above PA = £35,000 − £12,570 = £22,430. Basic-rate band remaining = £37,700 − £22,430 = £15,270. Taxable gains = £20,000 − £3,000 = £17,000. £15,270 taxed at 18% = £2,748.60. £1,730 taxed at 24% = £415.20. Total CGT = £3,163.80.
Frequently asked questions
What is the Capital Gains Tax allowance for 2025/26?
The Annual Exempt Amount for 2025/26 is £3,000. The first £3,000 of net gains in the tax year is tax-free. This was reduced from £6,000 in 2023/24 and £12,300 in 2022/23 — a real-terms cut that pulls many more disposals into CGT than five years ago.
What rate of Capital Gains Tax do I pay in 2025/26?
For disposals in 2025/26, CGT is 18% if the gain falls within your remaining basic-rate band, and 24% on any amount above it. The rates were unified by the October 2024 Budget — previously, non-residential gains were taxed at 10% / 20% but residential property was already 18% / 24%. From 6 April 2025, both asset classes share the same rates.
Do I need to report Capital Gains Tax to HMRC?
Yes if your total gains exceed the £3,000 allowance, or if total proceeds (not gains) exceed £50,000 even when no tax is due. UK residential property disposals must be reported and the tax paid within 60 days of completion via the CGT on UK Property service. Other gains are reported on your Self Assessment return by 31 January after the tax year ends.
Can I offset losses against my capital gains?
Yes. Allowable losses on chargeable assets in the same tax year reduce your gains pound-for-pound before the £3,000 allowance is applied. Unused losses can be carried forward indefinitely but only used in a year where current-year gains exceed the allowance. Report losses to HMRC within four years of the tax year of the loss to keep them available.
Are gains inside an ISA or pension subject to CGT?
No. Gains realised inside a Stocks & Shares ISA, Innovative Finance ISA, or any pension wrapper (SIPP, workplace scheme) are completely exempt from CGT. Only disposals outside these wrappers count. Selling and rebuying within an ISA is not a CGT event; "Bed & ISA" — selling outside and buying back inside — does crystallise a CGT disposal on the sale.
Does this calculator handle Business Asset Disposal Relief or carried interest?
No. This calculator handles the standard CGT rates (18% / 24%) only. Business Asset Disposal Relief (BADR) is taxed at 14% for 2025/26 disposals, rising to 18% from April 2026, with a £1m lifetime limit and qualifying conditions. Carried interest is taxed at 32% from April 2025. Both need specialist advice — speak to an accountant.