How it works
What this calculadora actually does
Capital Gains Tax Estimator (UK) is built to give you a clean, explainable answer without the usual wall of ads — type the numbers, read the result, keep moving.
Lenders model this scenario with the same tools — no reason you should be in the dark. Think of the next 12 months in whole pounds or reais, not percentages — then run the sums and the rest of this page explains what the answer means.
CGT applies when you sell or give away chargeable assets above the annual exempt amount. Rates depend on total taxable income: for non-property gains, basic-rate taxpayers typically pay 10% on gains within the basic-rate band and 20% above; residential property carries 18%/28% bands. Always verify current thresholds on GOV.UK.
Following the method end to end
Here's what happens when you plug real numbers in.
CGT applies when you sell or give away chargeable assets above the annual exempt amount. Rates depend on total taxable income: for non-property gains, basic-rate taxpayers typically pay 10% on gains within the basic-rate band and 20% above; residential property carries 18%/28% bands. Always verify current thresholds on GOV.UK.
Scenarios where Capital Gains Tax Estimator (UK) pays off
Capital Gains Tax Estimator (UK) is aimed at people arriving with questions like these:
- "CGT annual exemption"
- "Capital gains tax rates UK"
- "CGT on shares"
- "Higher rate CGT"
- "What is capital gains tax uk"
- "How to calculate capital gains tax uk"
When it isn't the right tool
Every tool has an edge where it stops being the right answer. Capital Gains Tax Estimator (UK) is no exception:
- For legally binding tax or medical decisions — cross-check with HMRC, NHS or a qualified professional.
- For very large or very small extremes the rounding error outgrows the useful precision.
- When the underlying rate or threshold has changed since the page was last reviewed — always verify with the primary source.
- When the input you have is already a derived figure (net of something) — feeding it in as "gross" will double-subtract.
Mistakes we see over and over
Every time you run the sums for a new scenario, one of these creeps in — it's worth knowing them ahead of time.
- Mixing up units — grams in one field, ounces in another, then wondering why the answer is off.
- Treating a percentage as a whole number. 20% means 0.20 in the maths, not 20.
- Rounding at every step. Keep four decimals internally and only round the final number.
- Using last year's thresholds. If the page isn't dated, assume it's stale and check GOV.UK.
- Reading a tool like this as advice. It is maths, not a decision — the decision is still yours.
The sources behind the numbers
Where the maths needs an external authority, we cross-check against:
- GOV.UK
- HMRC
Works well alongside
If this question keeps coming up for you, the same cluster of tools usually comes next:
- ISA Allowance calculadora (UK) — Track use of the annual £20,000 ISA subscription limit across Cash and Stocks & Shares ISAs, and see how much headroom you have before the tax year ends.
- Stamp Duty calculadora (SDLT) — Work out Stamp Duty Land Tax on a UK property purchase — first-time buyer, main residence or additional property — for England and Northern Ireland.
- UK Income Tax calculadora — Calculate Income Tax on your UK earnings across the basic, higher and additional rate bands, with the personal allowance applied automatically.
- Dividend Tax calculadora (UK) — Work out income tax on dividends above the Dividend Allowance at basic, higher and additional rates — including typical director/shareholder scenarios for UK limited companies.
How we keep this accurate
Our calculadoras run on pure, unit-tested functions — the same logic lives in the browser and in the CI test suite. When tax rates, thresholds or official figures move, the update lands within 24 hours of the announcement. You can read the editorial policy and corrections policy.
Found an out-of-date number on Capital Gains Tax Estimator (UK) or anywhere else in the Finance toolkit? Send it to the editorial desk and we'll patch it. Or browse the full calculadora directory for the next tool you need.