Capital Gains Tax Calculator
Enter your capital gain and your other taxable income for the year, and this calculator gives you an instant estimate of the Capital Gains Tax you're likely to owe.
It's built for a quick, ballpark answer when you're weighing up a sale or planning ahead — not a substitute for an actual disposal calculation, which depends on exact costs, dates and reliefs specific to your situation. It also doesn't cover Business Asset Disposal Relief, which has its own lower rate and eligibility conditions. If you're selling something significant, a specialist can confirm the exact figure and flag any reliefs worth claiming before you complete.
These figures are unofficial, indicative estimates only — not a tax return, an HMRC calculation, or financial, tax or legal advice. Always confirm your position with a qualified accountant or tax adviser before acting on it.
Gains on your only or main home are usually fully exempt via Private Residence Relief — this calculator is for a second home, buy-to-let or other residential property.
Sale price minus what you originally paid and any allowable costs (e.g. purchase/sale fees, improvement costs) — not the sale price itself.
Used to work out how much of your basic rate band is left for the gain — not the gain itself.
Estimated CGT owed
£3,618
Rates & assumptions used
- Annual exempt amount: £3,000, used against this gain first
- Basic rate: 18%, on the portion of the gain within your remaining basic rate band (£37,700 wide in total)
- Higher rate: 24%, on any gain above your basic rate band
- Property and shares/other assets now share the same rates — they were taxed differently before 2024/25
- Doesn’t account for Business Asset Disposal Relief, which has its own lower rate and eligibility rules
- Assumes England, Wales or Northern Ireland rates, and that this is your only capital gain for the year
Where your gain goes
- Gain before exemption
- £20,000
- Annual exempt amount used
- − £3,000
- Taxable gain
- £17,000
- Taxed at 18% (basic rate)
- £1,386
- Taxed at 24% (higher rate)
- £2,232
- Total Capital Gains Tax
- £3,618
- Estimated net proceeds from the gain
- £16,382
This is an estimate for planning purposes only, not a tax return or financial advice. Property gains also usually need reporting and paying within 60 days of completion, separately from Self Assessment.
For the full picture, see our complete Capital Gains Tax guide, or head straight to Capital Gains Tax support.
How this works
- 1Choose whether you're selling residential property (not your main home) or shares/other assets — both are taxed at the same rates currently, but this keeps the calculator relevant to your situation.
- 2Enter your capital gain — the profit after deducting what you paid and allowable costs, not the sale price itself.
- 3Enter your other taxable income for the year, after your Personal Allowance, so the calculator knows how much of your basic rate band is left.
- 4The calculator applies your annual exempt amount first, then splits the remaining taxable gain across the basic and higher CGT rates based on your income.
- 5Everything updates instantly as you type — there's nothing to submit and nothing is saved or sent anywhere.
FAQs
Capital Gains Tax Calculator questions
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