Figures checked on 24 September 2026
Each tax year, the first £3,000 of your net gains is free of Capital Gains Tax. That's the annual exempt amount, down from £12,300 in 2022/23, and whatever you don't use is lost. A gain only counts when it's realised by a disposal — usually a sale — and losses made in the same year are deducted first. Above the allowance, gains on shares and funds are taxed at 18% where they fall within your basic-rate band and 24% above it, the rates since 30 October 2024. Gains inside an ISA or a pension aren't taxed at all.
Two details change the arithmetic. Losses you can't use are carried forward to later years, but only if you report them to HMRC within four years of the end of the tax year you made them. And gains on an offshore fund without reporting fund status are generally taxed as income instead. The app's Realised Gains covers all time, includes holdings in ISAs and pensions and uses one average cost, so it isn't a CGT figure. The Tax Year widget's gains are: one tax year's sales from general accounts, matched with HMRC's same-day, 30-day and pooling rules. It doesn't know about losses from earlier years.
Illustrative, at 2026/27 rates: £900 at 18%, £1,200 at 24%. Your income decides the rate, or how the gain splits between the two.
Educational content only. It is not personal financial advice.