Capital Gains Tax on a £20,000 Gain 2026/27
After the £3,000 annual exempt amount, a basic-rate taxpayer (£35,000 other income) owes £3,164 CGT on a £20,000 gain. A higher-rate taxpayer (£55,000 other income) owes £4,080.
£20,000 is the first gain on this list where a typical basic-rate taxpayer pays both rates. After the allowance £17,000 is taxable, but someone on £35,000 has only £15,270 of basic-rate band left, so £1,730 goes at 24% and the bill is £3,163.80 rather than a straight 18%. A higher-rate seller pays £4,080.
Which rate does a £20,000 gain pay at different incomes?
| Other income | Band left | At 18% | At 24% | CGT |
|---|---|---|---|---|
| £20,000 | £30,270 | £17,000 | £0 | £3,060 |
| £35,000 | £15,270 | £15,270 | £1,730 | £3,163.80 |
| £45,000 | £5,270 | £5,270 | £11,730 | £3,763.80 |
| £55,000 | £0 | £0 | £17,000 | £4,080 |
The whole gain fits at 18% only up to an income of £33,270, so a part-time earner on £20,000 pays £3,060. At £45,000 most of it, £11,730, is already at 24%. Each extra £1,000 of salary above £33,270 moves £1,000 of gain from 18% to 24%, costing £60, until the gain is entirely in the higher rate at £50,270.1
Can you pay less on a £20,000 gain?
| Option | CGT | Saving |
|---|---|---|
| Sell it all in 2026/27 | £4,080 | - |
| Half before 6 April 2027, half after | £3,360 | £720 |
| Half given first to a spouse with no income | £2,940 | £1,140 |
| Half given first to a spouse earning £35,000 | £2,940 | £1,140 |
| £10,000 gross pension contribution | £3,763.80 | £316.20 |
| £20,000 gross pension contribution | £3,163.80 | £916.20 |
Spreading the sale over two tax years
Selling half in each tax year saves £643.80 for the £35,000 earner, more than the second allowance alone, because each half then fits inside the basic-rate band. For a higher-rate seller the saving is £720, the second allowance at 24%. It needs a divisible asset: shares, fund units or cryptoassets, not a single property.
Giving half to a spouse or civil partner
Moving half to a spouse with no income saves £1,140. With a spouse on £35,000 the saving is the same, £1,140, because their £10,000 share sits entirely within their band. Two higher-rate partners save £720. Your spouse inherits your purchase cost, so the household gain is unchanged; only where it is taxed moves.2
Pensions, ISAs and reliefs
For the £35,000 earner, the £1,730 that spills into 24% is cheap to fix through a workplace pension: £1,730 more by salary sacrifice or net pay lowers taxable pay by the same amount and keeps the whole gain at 18%, saving £103.80. Finance Act 2004 section 192(4) extends the basic rate limit for a personal pension contribution only where some income would otherwise be taxed at the higher rate, so at £35,000 the workplace route is the safe one.3 For a higher-rate seller a £20,000 gross contribution saves £916.20; the first £4,730 goes on bringing income down to £50,270 before any of the gain benefits.
Reporting and paying the tax
A gain this size is always reportable because there is tax due. If it came from selling cryptoassets, it is a capital gain like any other,6 with the same deadlines for a 2026/27 disposal: 31 December 2027 through the real-time service or 31 January 2028 on a tax return.4 If it came from a buy-to-let, report and pay within 60 days of completion.5
Your own figures: use the full calculator → for your sale price, costs, losses and income.
CGT on other gain amounts
Frequently asked questions
Why does a basic-rate taxpayer pay 24% on part of a £20,000 gain?
Because the gain is added on top of your income to decide the rate. On £35,000 of income you have £15,270 of basic-rate band left; the £17,000 taxable gain is bigger, so £1,730 goes over the top at 24%.
How much is CGT on £20,000 for someone with no other income?
The full £37,700 basic-rate band is free, so all £17,000 is taxed at 18%: £3,060, the same as for a part-time earner on £20,000.
Can I give £20,000 of shares to my adult child to use their allowance?
Not without tax. A gift to anyone other than your spouse, civil partner or a charity is treated as a disposal at market value on the date of the gift, so you pay CGT on the gain as if you had sold. Our CGT on gifts guide explains how it works.
Figures from our calculator engine, 7 November 2026. Guidance only, not advice.
Sources & references
The rates, allowances and rules in this guide are drawn from the official HMRC and GOV.UK sources below, checked for the 2026/27 tax year. Each link opens the relevant government page in a new tab.
- Capital Gains Tax: rates www.gov.uk/capital-gains-tax/rates
- Capital Gains Tax: gifts to your spouse or charity www.gov.uk/capital-gains-tax/gifts
- Finance Act 2004, section 192: relief at source (basic rate limit increased by the contribution) www.legislation.gov.uk/ukpga/2004/12/section/192
- Report and pay CGT: if you have other capital gains to report www.gov.uk/report-and-pay-your-capital-gains-tax/if-you-have-other-capital-gains-to-report
- Report and pay CGT: if you sold a UK property on or after 6 April 2020 www.gov.uk/report-and-pay-your-capital-gains-tax/if-you-sold-a-property-in-the-uk-on-or-after-6-april-2020
- Check if you need to pay tax when you sell cryptoassets www.gov.uk/guidance/check-if-you-need-to-pay-tax-when-you-sell-cryptoassets