How Do You Calculate Cgt

Calculate your potential capital gains tax liability based on your asset type, acquisition details, and personal circumstances.

Complete Guide: How to Calculate Capital Gains Tax (CGT) in the UK

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 to calculate CGT correctly can help you plan your finances and potentially reduce your tax liability. This comprehensive guide explains everything you need to know about calculating CGT in the UK.

What is Capital Gains Tax?

Capital Gains Tax is levied on the profit (or ‘gain’) you make when you sell or dispose of an asset. It’s important to note that:

• You only pay tax on the gain, not the total amount you receive
• Not all assets are subject to CGT (your main home usually qualifies for Private Residence Relief)
• You don’t pay CGT on assets you give to your spouse or civil partner
• There’s an annual tax-free allowance (£6,000 for 2023-24, reducing to £3,000 from April 2024)

Which Assets Are Subject to CGT?

You may need to pay Capital Gains Tax when you dispose of:

• Property that’s not your main home
• Shares that aren’t in an ISA or PEP
• Business assets
• Cryptocurrencies
• Personal possessions worth £6,000 or more (excluding your car)
• Your main home if you’ve let it out, used it for business, or it’s very large

Step-by-Step: How to Calculate Your Capital Gains Tax

1. Determine your gain

   Calculate the gain by subtracting the acquisition cost from the disposal proceeds:

   Gain = Disposal Proceeds – (Acquisition Cost + Improvement Costs + Selling Costs)

   For example, if you bought a property for £200,000, spent £30,000 on improvements, and sold it for £350,000 with £5,000 in selling costs:

   Gain = £350,000 – (£200,000 + £30,000 + £5,000) = £115,000

2. Apply any reliefs

   Certain reliefs can reduce your gain:

   • Private Residence Relief: If the asset was your main home at any time
   • Business Asset Disposal Relief: For qualifying business assets (10% tax rate)
   • Gift Hold-Over Relief: If you gave away business assets
   • Investors’ Relief: For certain share disposals (10% tax rate)
3. Deduct your annual exempt amount

   For 2023-24, the annual exempt amount is £6,000 (reducing to £3,000 from April 2024). This is the amount of gain you can make each year without paying CGT.

   Taxable Gain = Total Gain – Annual Exempt Amount – Any Losses

4. Calculate the tax due

   The tax rate depends on:

   • Your income tax band
   • The type of asset

   Asset Type	Basic Rate Taxpayer	Higher/Additional Rate Taxpayer
   Residential Property	18%	28%
   Other Chargeable Assets	10%	20%
   Business Asset Disposal Relief assets	10%

5. Report and pay

   You must report and pay any CGT you owe:

   • For property disposals: Within 60 days of completion
   • For other assets: Through your Self Assessment tax return by 31 January following the end of the tax year

Capital Gains Tax Allowances and Rates (2023-24)

Tax Year	Annual Exempt Amount	Basic Rate (other assets)	Basic Rate (property)	Higher Rate (other assets)	Higher Rate (property)
2023-24	£6,000	10%	18%	20%	28%
2024-25	£3,000	10%	18%	20%	28%
2022-23	£12,300	10%	18%	20%	28%

Common Mistakes to Avoid When Calculating CGT

• Forgetting to include all costs: Remember to include improvement costs and selling fees in your calculations
• Incorrectly calculating the gain: Always use the actual acquisition cost, not the current market value
• Missing deadlines: Property disposals must be reported within 60 days
• Not using your annual exemption: Everyone gets an annual tax-free allowance – use it!
• Ignoring reliefs: Many people qualify for reliefs but don’t claim them
• Not keeping records: HMRC can ask for evidence up to 6 years after the tax year

How to Reduce Your Capital Gains Tax Bill

There are several legitimate ways to reduce your CGT liability:

1. Use your annual exemption

   Both you and your spouse/civil partner have an annual exemption (£6,000 each for 2023-24). Transferring assets between you can help use both allowances.

2. Time your disposals

   If you have gains close to the annual exemption, consider spreading disposals over two tax years to use two annual exemptions.

3. Offset losses

   Capital losses can be offset against gains in the same tax year or carried forward to future years.

4. Claim reliefs

   Make sure you claim all reliefs you’re entitled to, such as:

   • Private Residence Relief for property that was your main home
   • Business Asset Disposal Relief (10% tax rate) for qualifying business assets
   • Gift Hold-Over Relief when giving away business assets
5. Use tax-efficient accounts

   Assets held in ISAs or pensions are free from CGT.

6. Consider Bed and ISA

   Sell shares and immediately repurchase them within an ISA to crystalise gains within the annual exemption.

7. Bed and Spouse

   Transfer assets to your spouse (tax-free) who may have unused annual exemption or pay tax at a lower rate.

Capital Gains Tax on Property

Property often attracts the highest CGT rates (18% or 28%), so special rules apply:

• Private Residence Relief: If the property was your main home for all the time you owned it, you usually don’t pay CGT. If you lived there for only part of the time, you may get partial relief.
• Letting Relief: If you let out a property that was once your main home, you may get up to £40,000 relief (reducing to £0 from April 2024).
• Final Period Exemption: The last 9 months of ownership always qualify for relief, even if you weren’t living there.
• Married Couples: Only one property can be nominated as your main home at any time.

Scenario	Potential Relief	2023-24 Tax Rate
Main home (always lived in)	Full Private Residence Relief	0%
Main home (lived in for 3 of 5 years)	60% Private Residence Relief + 9 months	18% or 28% on remaining gain
Second home	None (unless it was your main home at some point)	18% or 28%
Rental property (never lived in)	None	18% or 28%
Inherited property	None (unless it became your main home)	18% or 28%

Capital Gains Tax on Shares and Investments

When selling shares or investments, special rules apply:

• Share Pooling: If you bought shares at different times, you need to calculate the average cost.
• Same-Day Rule: Shares bought and sold on the same day are matched first.
• 30-Day Rule: Shares bought within 30 days of selling are matched with the sale.
• Section 104 Holding: Any remaining shares go into a ‘pool’ with an average cost.
• Dividends: These are taxed separately and don’t affect your CGT calculation.

For example, if you bought:

• 100 shares at £10 each in January
• 200 shares at £15 each in March
• Then sold 150 shares at £20 each in June

You would use the first 100 shares (same-day rule doesn’t apply here) and 50 from the March purchase, calculating the gain separately for each tranche.

Capital Gains Tax on Cryptocurrency

HMRC treats cryptocurrency as property for CGT purposes. Key points:

• Every crypto-to-crypto trade is a taxable disposal
• You need to calculate the pound sterling value at the time of each transaction
• The ‘share pooling’ rules apply to crypto assets
• Mining, staking rewards, and airdrops are usually taxable as income
• You can’t offset income tax against capital losses

For example, if you:

1. Buy 1 Bitcoin for £10,000
2. Later buy 0.5 Bitcoin for £6,000 (when Bitcoin is £12,000 each)
3. Sell 1 Bitcoin for £15,000

You would calculate the gain using the pooled average cost of £10,666.67 per Bitcoin.

Reporting and Paying Capital Gains Tax

How and when you report and pay CGT depends on the type of asset:

Asset Type	Reporting Deadline	Payment Deadline	How to Report
UK Residential Property	Within 60 days of completion	Within 60 days of completion	Online via GOV.UK service
Other Assets (shares, crypto, etc.)	By 31 January after tax year ends	By 31 January after tax year ends	Self Assessment tax return
Non-residents disposing of UK property	Within 60 days of completion	Within 60 days of completion	Online via GOV.UK service

You’ll need to keep records of:

• Dates and values when you acquired and disposed of assets
• Costs of acquisition, improvement, and disposal
• Any reliefs or exemptions claimed
• Calculations showing how you worked out your gain

HMRC can ask for these records up to 6 years after the tax year they relate to (or up to 20 years in cases of fraud or failure to notify).

Capital Gains Tax for Non-UK Residents

If you’re not resident in the UK, you may still need to pay CGT on:

• UK residential property (since April 2015)
• All UK property and land (since April 2019)
• Certain UK assets if you return to the UK within 5 years of leaving

Non-residents have the same annual exemption as UK residents (£6,000 for 2023-24) but can only use it against UK gains. The reporting and payment deadline is within 60 days of completion for property disposals.

Capital Gains Tax and Inheritance

When you inherit an asset, you’re treated as acquiring it at its market value at the time of death (not what the original owner paid for it). This is called the ‘probate value’.

For example, if your parent bought a property for £50,000 in 1980 and it was worth £300,000 when they died in 2023, your acquisition cost for CGT purposes would be £300,000. If you later sell it for £350,000, your gain would be £50,000.

Special rules apply if:

• The asset was given away within 7 years of death (it may be subject to Inheritance Tax instead)
• The asset qualifies for Business Property Relief or Agricultural Property Relief
• The estate includes assets that have increased in value since death

Capital Gains Tax and Divorce

Special rules apply when transferring assets between divorcing or separating couples:

• Transfers between spouses are normally free from CGT
• This continues until the end of the tax year in which you separate
• After separation, you may still transfer assets tax-free if under a court order
• The receiving spouse takes over the original acquisition cost

For example, if you transfer a rental property worth £250,000 (original cost £150,000) to your ex-spouse as part of a divorce settlement, there would be no immediate CGT liability. Your ex-spouse would take over your original acquisition cost of £150,000.

Capital Gains Tax Planning Strategies

With careful planning, you can legally reduce your CGT liability:

1. Use your annual exemption every year

   If you have large gains, consider realising them over several tax years to use multiple annual exemptions.

2. Transfer assets to your spouse

   Transfers between spouses are CGT-free, allowing you to use both annual exemptions and potentially benefit from lower tax bands.

3. Invest in tax-efficient accounts

   Hold investments in ISAs or pensions where gains are tax-free.

4. Claim all available reliefs

   Make sure you’re claiming all reliefs you’re entitled to, such as Private Residence Relief or Business Asset Disposal Relief.

5. Offset losses against gains

   Capital losses can be offset against gains in the same tax year or carried forward to future years.

6. Consider timing of disposals

   If you’re close to the boundary between tax bands, timing disposals could mean paying tax at a lower rate.

7. Use Bed and ISA or Bed and Spouse

   These strategies can help crystalise gains within the annual exemption.

8. Gift assets during your lifetime

   Gifting assets can reduce your estate for Inheritance Tax purposes and may allow the recipient to benefit from a higher acquisition cost (though Gift Hold-Over Relief may apply to business assets).

Important Disclaimer: This calculator and guide provide general information only. Capital Gains Tax rules are complex and depend on your individual circumstances. For specific advice, always consult a qualified tax advisor or accountant. The information here is based on UK tax law as of the 2023-24 tax year and may be subject to change.

Authoritative Resources

For official information on Capital Gains Tax, consult these authoritative sources:

• GOV.UK: Capital Gains Tax Overview
• GOV.UK: CGT Rates and Allowances
• University of Cambridge: Capital Gains Tax Research