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Legal Ways to Reduce Capital Gains Tax
1. Use ISAs and pensions
Gains on assets held inside a Stocks & Shares ISA or a pension are never subject to CGT. "Bed and ISA" — selling and immediately repurchasing inside an ISA — moves existing holdings into that shelter using your £20,000 annual ISA allowance.
2. Use both spouses' allowances
Transfers of assets between spouses and civil partners are tax-free. Splitting ownership of an asset before sale means both partners' £3,000 annual exempt amounts apply to the combined disposal.
3. Time disposals across tax years
Splitting a large disposal so part falls in one tax year and part in the next lets you use two years' worth of the £3,000 allowance instead of one.
4. Harvest losses
Losses on other assets sold in the same or a carried-forward tax year can be offset against gains, reducing the taxable amount before the allowance is even applied.
5. Business Asset Disposal Relief
Qualifying business disposals (e.g. selling your own trading company) can be taxed at 18% instead of the standard rates, up to a £1 million lifetime limit — strict conditions apply on ownership period and shareholding.
Important: these are legitimate reliefs and allowances built into the tax system — not avoidance schemes. Eligibility rules are specific; always confirm your position with HMRC guidance or a qualified adviser before relying on one.
How this calculator works — Formulas & Method
Source: gov.uk/capital-gains-tax/rates, gov.uk/business-asset-disposal-relief · Deterministic calculation — no AI, no arbitrary estimation
Constants used
| Constant | Value | Source |
|---|---|---|
| Annual exempt amount | £3,000 (per person, per tax year) | gov.uk/capital-gains-tax/rates |
| ISA annual allowance | £20,000 | gov.uk/individual-savings-accounts |
| BADR rate | 18%, £1m lifetime limit | gov.uk/business-asset-disposal-relief |
Formulas
taxable_gain = max(0, gain − £3,000)
— Spousal split example —
combined_allowance = £3,000 × 2 (if asset transferred/co-owned before sale)
— Rate band —
basic_band_remaining = max(0, £50,270 − other_taxable_income)
cgt = min(taxable_gain, basic_band_remaining) × 18% + rest × 24%
Deterministic calculation. Reliefs shown are the standard, published mechanisms — eligibility depends on your specific circumstances; always confirm with HMRC or a qualified adviser.
Get Independent Financial Advice
This figure is an estimate — deciding how it fits into your wider finances is a bigger decision worth getting right.
- Considering a specific relief: Business Asset Disposal Relief, Gift Hold-Over Relief and loss harvesting all have strict qualifying conditions worth checking before you rely on them.
- Multiple allowances to use: spouses/civil partners each get their own £3,000 CGT allowance — transferring assets between you before disposal can double what's tax-free.
- Large one-off gain: understand how it interacts with your Income Tax band and other allowances for the year.
An FCA-regulated independent financial adviser can model your specific numbers — free directories like Unbiased.co.uk match you with a local IFA.
Find an Independent Financial Adviser →Transparency & Methodology
Methodology & Sources
Figures are public HMRC rates. For your exact position, use gov.uk/capital-gains-tax.
Not Tax or Legal Advice
Information only. Consult the Chartered Institute of Taxation or an adviser via the FCA Register.
Open Source
Formulas are public. Inspect on GitHub.