How does capital gains tax work?
- Nic Round: Chartered Wealth Manager
- Feb 13
- 3 min read
Updated: 1 day ago
How does capital gains tax work?
In the UK, Capital Gains Tax (CGT) is charged on the profit you make when you sell or dispose of certain assets. It is not charged on the total sale price, only on the gain.
Behind this question are usually practical concerns:
How much tax will I actually pay?
Is my home included?
Are there allowances?
Can I reduce the tax legally?
Understanding how capital gains tax works helps you plan sales more carefully.
What counts as a capital gain?
A capital gain is the difference between:
What you paid for an asset
What you sell it for
After allowable costs are deducted.
Assets commonly subject to CGT include:
Shares and investments
Buy-to-let property
Second homes
Business assets
Valuable personal possessions above certain thresholds
Your main residence is usually exempt under Private Residence Relief.
The annual capital gains tax allowance
Each individual has an annual CGT allowance.
If your total gains in a tax year fall below this threshold, you may not owe capital gains tax.
If your gains exceed the allowance, only the amount above the threshold is taxable.
This allowance can change between tax years, so checking the current level is important.
How capital gains tax is calculated
Capital gains tax is calculated on:
Sale priceminusPurchase priceminusAllowable costsminusAnnual allowance
Allowable costs may include:
Stamp duty when purchased
Estate agent fees
Legal fees
Certain improvement costs
The remaining taxable gain is then taxed at rates that depend on:
Your income tax band
The type of asset
Residential property gains are typically taxed at higher rates than most other assets.
A simple example
Imagine:
You bought shares for £50,000
You sell them for £90,000
Gain = £40,000
If your annual CGT allowance is, for example, £6,000:
Taxable gain = £34,000
If you are a higher-rate taxpayer and CGT applies at 20% on shares:
20% of £34,000 = £6,800
You do not pay tax on £90,000.You pay tax on the gain above the allowance.
When capital gains tax becomes more complex
CGT often feels simple in theory but becomes more nuanced when:
Assets are jointly owned
Income fluctuates between tax bands
Business Asset Disposal Relief may apply
Transfers occur between spouses
Sales are spread across tax years
Timing can significantly influence tax outcome.
For example, splitting a disposal across two tax years may allow use of two annual allowances.
The behavioural layer
Often the real worry is not the formula.
It is:
Selling at the wrong time
Creating an unexpected tax bill
Not understanding how gains interact with income
Triggering tax unnecessarily
Capital gains tax planning is usually about sequencing and timing, not avoidance.
Clarity before selling often prevents regret later.
A more useful question
Rather than asking only:
How does capital gains tax work?
A more practical question might be:
What will the net outcome be after tax if I sell now?
That shifts the focus from rules to consequences.
And consequences are what shape decisions.
Some of the most common practical questions people ask about capital gains tax are below.
Do I pay capital gains tax on my main home?
Most primary residences are exempt from capital gains tax under Private Residence Relief.
How much is capital gains tax in the UK?
Rates depend on income level and asset type. Residential property is generally taxed at higher rates than shares and investments.
Can I reduce capital gains tax legally?
Certain reliefs, allowances and timing strategies may reduce CGT, depending on individual circumstances.
Do spouses pay capital gains tax on transfers between them?
Transfers between spouses or civil partners are usually free from capital gains tax at the point of transfer.
A calm place to think first
If you are considering selling an asset and are concerned about capital gains tax, you may not need immediate action.
Often the first step is to clarify:
The likely gain
The available allowance
How the gain interacts with your income
Evoa exists to provide that quiet thinking space — before advice, before action.
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