UK Capital Gains Tax: Complete Guide to Shares, Property and Crypto

Only gains above the £3,000 annual allowance are taxable. The allowance used to be £12,300 in 2022/23, halved to £6,000 in 2023/24, and halved again to £3,000 for 2024/25 onwards. Trusts get half the individual allowance.

Rates are determined by what you're selling and your total income. The 30 October 2024 Budget raised non-property rates to match property rates. Disposals before that date used the older lower rates — transactions straddling the date split.

Your basic/higher rate is determined by stacking the gain on top of your income. A £20,000 gain on top of a £45,000 salary uses some basic-rate band (£5,270 at 18%) and the rest at higher rate (£14,730 at 24%).

Selling a UK residential property that isn't your main home? You must file and pay within 60 days of completion. This is a standalone return, not part of Self Assessment — though the gain also appears on your annual return.

• Your main home (Principal Private Residence) is normally fully exempt.
• If you let out a former main home, PPR relief covers the period of actual occupation plus the final 9 months.
• Second homes, buy-to-lets, and inherited properties sold are all caught.
• The 60-day deadline runs from completion date, not exchange. Missed returns attract £100 penalties that escalate.

Selling shares held outside an ISA/pension? The matching rules determine which "units" of your holding you sold for calculating gain:

• Same-day rule — shares sold and bought the same day are matched first.
• 30-day "bed and breakfasting" rule — shares bought back within 30 days are matched to the sale. This stops quick reset-and-realise schemes.
• Section 104 pool — all remaining shares are treated as one averaged pool at their average cost.

Bed and ISA is still legal — sell outside an ISA and rebuy inside within 30 days doesn't trigger the 30-day rule because the ISA shares are a different asset class for CGT purposes.

Cryptocurrency is treated as an asset, not currency. Every disposal is potentially taxable:

• Selling crypto for GBP — CGT event.
• Swapping one crypto for another — CGT event (common surprise). Even ETH → wBTC triggers a disposal.
• Using crypto to buy goods/services — CGT event.
• Sending crypto to another wallet you own — NOT a disposal.
• Gifting to a spouse — not a disposal (no gain, no loss).
• Gifting to anyone else — CGT event at market value on the day.

HMRC is increasingly active in crypto. Centralised exchanges (Coinbase, Binance UK) report to HMRC. The Crypto Disclosure Facility exists specifically to let people come forward before HMRC finds them.

Capital losses are valuable. Rules:

• Losses in a tax year are set off against gains in the same year before the £3,000 allowance.
• Unused losses carry forward indefinitely — but must be claimed within 4 years of the loss year.
• Losses on "negligible value" shares can be claimed even without selling, if you can prove the share is worthless.

• Use both spouses' allowances — transfer assets between spouses (no CGT) to use two £3,000 allowances.
• Time disposals across tax years — sell some in March, rest in April to use two allowances.
• Hold inside an ISA/SIPP — no CGT at all.
• Hold until death — assets are rebased at probate value and CGT history is wiped (though they may face IHT at 40%).
• Claim PPR relief correctly — elect which property is your main home within 2 years of owning a second if it matters.