UK Capital Gains Tax Calculator
Estimate your Capital Gains Tax (CGT) based on common UK rules. Enter your numbers below and click calculate.
Important: This is an educational estimate, not personal tax advice. UK tax law changes, and special rules can apply (main residence relief, non-resident rules, trust rates, spouses, etc.).
How this UK capital gains calculator works
This calculator estimates Capital Gains Tax by following a simplified version of HMRC-style steps:
- Work out your gross gain: sale proceeds minus purchase price and allowable costs.
- Deduct losses, reliefs, and your annual exempt amount.
- Split taxable gain into lower-rate and upper-rate portions based on your taxable income and remaining basic rate band.
- Apply rates based on asset type (for example 10%/20% for many assets, 18%/24% for residential property).
It gives you a clear estimate and a breakdown so you can plan ahead before disposal.
What counts as allowable costs?
Allowable costs can reduce your taxable gain significantly. Common examples include:
- Acquisition costs (e.g., stamp duty and legal fees when buying).
- Disposal costs (e.g., solicitor and estate agent costs when selling).
- Capital improvements that enhance value (not normal repairs or maintenance).
- Brought-forward losses from prior tax years if properly claimed.
Keeping records and invoices is crucial in case HMRC requests evidence.
Quick example calculation
Scenario
You sell an asset for £250,000 that you bought for £180,000. You also have:
- Acquisition + disposal + improvement costs: £10,000 total
- Brought-forward losses: £2,000
- Annual exempt amount: £3,000
Your gross gain is £60,000. After losses and allowance, taxable gain is £55,000. Depending on your taxable income and asset type, part may be charged at the lower rate and the rest at the upper rate. The calculator handles that split automatically.
Current UK CGT planning ideas (legal and practical)
1) Use your annual exempt amount each year
Where possible, consider timing disposals across tax years to use allowances more efficiently.
2) Realise losses strategically
Capital losses can offset gains. Properly reported losses may reduce your bill now or later.
3) Consider spouse/civil partner transfers
Transfers between spouses/civil partners can often be made on a no-gain/no-loss basis, which may help use both allowances and bands.
4) Review relief eligibility early
Certain disposals may qualify for reliefs such as Business Asset Disposal Relief. Eligibility details matter, so verify conditions before you sell.
Frequently asked questions
Do I pay CGT on my main home?
Often no, due to Private Residence Relief, but it depends on use history (for example, periods of letting or partial business use can affect outcomes).
Is this calculator suitable for every case?
No. It is a practical estimate tool for common scenarios. Complex situations (non-UK residency, trusts, carried interest, crypto-specific record issues, rebasing rules, etc.) need tailored advice.
What tax year rates does this use?
It uses standard rates shown in the calculator options and a default basic rate band input you can edit. Always confirm rates and thresholds for your exact tax year.
Final thoughts
If you are preparing to sell shares, property, funds, or another chargeable asset, a quick CGT estimate can help avoid surprises. Use this calculator to model scenarios, then confirm your figures with official HMRC guidance or a qualified tax adviser.