Capital Gains Tax Calculator: Estimate Your Tax Bill

Estimate capital gains tax on investments. Covers UK CGT rates, annual exempt amount, and basic vs higher rate tax.

EptaWealth Team
··Updated 31 Aug 2026

Capital gains tax applies when you sell investments for more than you paid. But calculating your actual liability involves the annual exempt amount, your income tax band, and different rates for different asset types.

This calculator estimates your CGT bill based on current UK rates. Enter your gain, select your tax band, and see how much you'll owe — plus how much of your annual exempt amount you've used.

Use it for tax planning: model selling in different tax years, splitting gains between spouses, or using your annual allowance strategically before year-end.

Inputs

£
£
£

Your salary before tax, not your taxable income. The personal allowance is deducted for you. This decides whether the gain is taxed at 18%, 24%, or partly at each.

Results

Capital Gain

£5,000

Taxable Gain

£2,000

After the £3,000 exempt amount

Tax Rate Applied

18% and 24%

9.28% effective, across the whole gain

Estimated Tax Owed

£464

Tax Summary

Purchase Price£10,000
Sale Price£15,000
Capital Gain£5,000
Annual exempt amount (2026/27)£3,000
£270 at 18%£49
£1,730 at 24%£415
Tax Owed£464
Net Proceeds After Tax£4,536

Assumptions

  • 2026/27 rates: 18% within the basic rate band, 24% above it. The basic rate band is £37,700 of taxable income.
  • Annual exempt amount £3,000, and this is your only disposal this tax year.
  • Personal allowance £12,570, tapered above £100,000 of income.
  • Allowable costs such as broker fees and stamp duty are not included. Adding them reduces the gain.
  • Residential property carries the same rates but must be reported and paid within 60 days of completion.

This is an estimate for information only, not tax advice. Figures depend on your full circumstances. Check the rules at GOV.UK.

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