cgt calculator uk

How UK Capital Gains Tax works

Capital Gains Tax is charged on the profit (gain) when you sell or dispose of a chargeable asset. You usually pay tax on the gain, not the full sale value. In simple terms:

Gain = Sale proceeds - (purchase cost + allowable costs + improvement costs)

Then you normally deduct any allowable capital losses and your annual exempt amount to work out the taxable gain. The tax rate depends on your income and the type of asset sold.

What this CGT calculator includes

• Sale value, purchase value, buying/selling costs, and improvement costs
• Current year and brought-forward capital losses
• Annual exempt amount (editable)
• Basic rate band interaction using your taxable income
• Different rates for standard assets and residential property

What this calculator does not include

• Detailed private residence relief calculations
• Business Asset Disposal Relief lifetime tracking
• Trust, company, or non-UK resident specific rules
• Special pooling/matching scenarios beyond a simple estimate

CGT rates at a glance (individuals)

Asset type	Lower rate (within basic rate band)	Higher rate (above basic rate band)
Most assets (shares, funds, etc.)	10%	20%
Residential property (not fully exempt)	18%	24% (28% for 2023/24 in this tool)

Step-by-step: using the calculator correctly

1) Enter accurate proceeds and cost basis

Use your actual disposal proceeds and include all allowable acquisition and disposal costs. For shares, this is often based on HMRC share matching rules and pooled costs.

2) Add only capital improvements

Repairs and maintenance are usually income expenses, not capital improvements. Improvements generally add value or extend life.

3) Include capital losses

Losses can reduce your taxable gain. Make sure brought-forward losses are allowable and properly reported.

4) Enter taxable income

Your taxable income affects how much of the gain can use the lower CGT rate before higher rates apply.

Worked example

Imagine you sell an investment asset for £150,000. You bought it for £100,000, had £3,000 buying costs, £2,500 selling costs, and £10,000 improvements. You also have £6,000 total losses and a £3,000 annual exemption.

• Gross gain: £150,000 - (£100,000 + £3,000 + £2,500 + £10,000) = £34,500
• After losses: £34,500 - £6,000 = £28,500
• After annual exemption: £28,500 - £3,000 = £25,500 taxable gain

The final tax depends on how much basic rate band remains after your taxable income.

Ways to reduce CGT legally

• Use annual exempt amount each tax year
• Realise losses strategically to offset gains
• Use tax wrappers like ISAs and pensions for future growth
• Consider transfers between spouses/civil partners where appropriate
• Keep strong records of purchase costs, fees, and improvements

Important reminder

UK tax rules can change and personal circumstances matter. Treat this page as a quick estimate, not formal advice. For significant disposals, consider checking HMRC guidance or speaking with a qualified UK tax adviser.