Capital Gains Tax (CGT) Calculator
How Is Capital Gains Tax (CGT) Calculated? A Complete Guide
Capital Gains Tax (CGT) is a tax on the profit you make when you sell (or ‘dispose of’) an asset that’s increased in value. Understanding how CGT is calculated can help you plan your finances more effectively and potentially reduce your tax liability.
What Counts as a Capital Gain?
A capital gain occurs when you sell an asset for more than you paid for it. Common assets subject to CGT include:
- Property that isn’t your main home
- Shares that aren’t in an ISA or PEP
- Business assets
- Cryptocurrency
- Personal possessions worth £6,000 or more (excluding your car)
The CGT Calculation Formula
The basic formula for calculating CGT is:
Taxable Gain = (Sale Proceeds – Purchase Cost – Allowable Expenses) – Annual Exempt Amount
Then:
CGT Due = Taxable Gain × Applicable CGT Rate
Step-by-Step CGT Calculation Process
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Determine the sale proceeds
This is the amount you received from selling the asset. For property, this is typically the sale price minus any selling costs like estate agent fees.
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Calculate the purchase cost
This includes:
- The original purchase price
- Purchase costs (legal fees, stamp duty, etc.)
- Costs of improvements (not repairs) that enhance the asset’s value
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Subtract allowable expenses
These are costs directly related to buying or selling the asset, such as:
- Valuation fees
- Advertising costs
- Professional fees (solicitors, accountants)
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Apply the annual exempt amount
For the 2023-24 tax year, the annual exempt amount is £6,000 for individuals (£3,000 for trusts). This is reducing to £3,000 for individuals in 2024-25.
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Determine your CGT rate
CGT rates depend on your income tax band and the type of asset:
Asset Type Basic Rate Taxpayer Higher/Additional Rate Taxpayer Residential Property (not main home) 18% 28% Other Chargeable Assets 10% 20% -
Calculate the tax due
Multiply the taxable gain by the appropriate rate(s). If your gain pushes you into a higher tax band, you may pay different rates on different portions of the gain.
Special Rules and Reliefs
Several special rules and reliefs can affect your CGT calculation:
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Private Residence Relief:
If you’re selling your main home, you typically don’t pay CGT on any gain, though there are exceptions if you’ve let out part of the property or used it for business.
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Letting Relief:
If you’ve let out a property that was once your main home, you may qualify for up to £40,000 of letting relief (reducing to £25,000 from April 2024).
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Business Asset Disposal Relief:
If you’re selling all or part of a business, you may qualify for a reduced 10% CGT rate on the first £1 million of gains over your lifetime.
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Gift Hold-Over Relief:
If you give away business assets or sell them for less than they’re worth, you may be able to defer paying CGT until the recipient sells them.
CGT Allowances and Thresholds
| Tax Year | Annual Exempt Amount (Individuals) | Annual Exempt Amount (Trusts) | Basic Rate CGT (Property) | Basic Rate CGT (Other Assets) | Higher Rate CGT (Property) | Higher Rate CGT (Other Assets) |
|---|---|---|---|---|---|---|
| 2023-24 | £6,000 | £3,000 | 18% | 10% | 28% | 20% |
| 2024-25 | £3,000 | £1,500 | 18% | 10% | 24% | 20% |
| 2025-26 (proposed) | £3,000 | £1,500 | 18% | 10% | 24% | 20% |
Common CGT Mistakes to Avoid
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Forgetting to include all costs
Many people only consider the purchase and sale price, forgetting to include legal fees, improvement costs, and other allowable expenses that can reduce their taxable gain.
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Incorrectly calculating the gain
It’s essential to calculate the gain correctly by subtracting all allowable costs from the sale proceeds before applying the annual exempt amount.
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Not using the annual exempt amount
Every individual has an annual CGT allowance. Not using it means paying more tax than necessary.
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Ignoring special reliefs
Many taxpayers miss out on valuable reliefs like Private Residence Relief or Business Asset Disposal Relief because they’re not aware of them.
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Not considering timing
The timing of asset sales can significantly impact your CGT liability, especially if you’re near the boundary between tax bands.
How to Reduce Your Capital Gains Tax
There are several legitimate ways to reduce your CGT bill:
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Use your annual exempt amount
Each tax year, you have an annual exempt amount (£6,000 in 2023-24, £3,000 in 2024-25). If you have gains, try to use this allowance each year.
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Transfer assets to your spouse
Transfers between spouses are CGT-free. This can allow you to use both of your annual exempt amounts.
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Use tax-efficient investments
Investments like ISAs and pensions are free from CGT. Consider using these before investing in taxable accounts.
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Offset losses against gains
If you have assets that have decreased in value, selling them can create a capital loss that can be offset against your gains.
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Consider timing
If you’re a basic rate taxpayer, spreading gains over several years can help you stay within the basic rate band and pay CGT at the lower rate.
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Claim all available reliefs
Make sure you’re claiming all the reliefs you’re entitled to, such as Business Asset Disposal Relief or Private Residence Relief.
CGT on Different Asset Types
The rules for calculating CGT can vary depending on the type of asset:
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Property:
For residential property that’s not your main home, you typically pay CGT at 18% (basic rate) or 28% (higher rate). You can deduct costs like estate agent fees, legal fees, and improvement costs.
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Shares:
When selling shares, you can deduct the purchase price, brokerage fees, and the costs of any share certificates. The CGT rates are 10% for basic rate taxpayers and 20% for higher rate taxpayers.
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Cryptocurrency:
Crypto assets are subject to CGT when you sell them for fiat currency, exchange them for other crypto, or use them to pay for goods or services. The rules are similar to shares, with rates of 10% or 20%.
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Business Assets:
If you’re selling business assets, you may qualify for Business Asset Disposal Relief (formerly Entrepreneurs’ Relief), which reduces the CGT rate to 10% on the first £1 million of gains over your lifetime.
When Do You Need to Pay CGT?
You need to pay CGT when you:
- Sell an asset for more than you paid for it
- Give away an asset (unless it’s to your spouse or a charity)
- Exchange an asset for something else
- Receive compensation, such as for a damaged asset
You don’t usually need to pay CGT when you:
- Sell your main home (though there are exceptions)
- Sell assets within an ISA or PEP
- Sell UK government gilts or Premium Bonds
- Bet or gamble
Reporting and Paying CGT
If you need to pay CGT, you must report it to HMRC. The process depends on the type of asset:
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Property:
You must report and pay any CGT due on UK residential property within 60 days of completion (30 days for sales completed before 27 October 2021).
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Other assets:
You report gains on other assets through your Self Assessment tax return. The deadline is 31 January following the end of the tax year.
You can report and pay CGT online through the GOV.UK Capital Gains Tax service.
Recent Changes to CGT Rules
The UK government has made several recent changes to CGT rules:
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Reduction in annual exempt amount:
The annual exempt amount was reduced from £12,300 to £6,000 in April 2023, and will be further reduced to £3,000 in April 2024.
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Extension of payment window for property:
The window for reporting and paying CGT on property sales was extended from 30 days to 60 days in October 2021.
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Changes to Business Asset Disposal Relief:
The lifetime limit for this relief was reduced from £10 million to £1 million in March 2020.
Important Disclaimer: This calculator and guide provide general information only. They don’t constitute tax advice. Capital Gains Tax rules can be complex, and your individual circumstances may affect your tax liability. For accurate advice tailored to your situation, consult a qualified tax advisor or accountant. The information provided is based on UK tax law as of the 2023-24 tax year and may be subject to change.
Further Resources
For more detailed information on Capital Gains Tax, consult these authoritative sources:
- GOV.UK: Capital Gains Tax – Official government guidance on CGT rules and rates
- GOV.UK: CGT Rates and Allowances – Current rates and annual exempt amounts
- ICAEW: Capital Gains Tax Guide – Comprehensive guide from the Institute of Chartered Accountants in England and Wales