Capital Gains Tax Calculator

Estimate UK Capital Gains Tax on shares, residential property and other chargeable assets using your gain, allowable costs, losses and taxable income.

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Disposal details

Supports verified 2024/25, 2025/26 and 2026/27 rules. Applicable rates are derived from the disposal date. Inputs can be restored in the current browser session. This is an estimate only and not a substitute for individual tax advice.

Asset type

Not every asset falls safely into one of these categories. Special-rule assets may need professional advice.

The disposal date determines the tax year and rate segment.

The amount paid to acquire the asset.

£

Enter allowable incidental acquisition costs, such as legal fees, broker fees, professional fees and Stamp Duty where applicable. Not every related cost is automatically allowable.

£

The amount received or treated as received on disposal.

£

Enter allowable incidental disposal costs, such as legal, broker or estate-agent fees. Do not include ordinary ownership or maintenance costs.

£

This is used to estimate how much of the taxable gain falls within the unused UK basic-rate band.

£

Enter unused allowable capital losses from earlier tax years. Not all entered losses will necessarily be used.

£

Capital Gains Tax rates are UK-wide. This only affects the Scottish band disclosure.

Capital Gains Tax results

Capital Gains Tax payable

£2,160.00

Effective CGT rate
18.0%
Taxable gain
£12,000.00
Tax year
2026/27
Asset class
Shares
Rate treatment
Entirely within unused basic-rate band

  • Capital gain

    £15,000.00

  • Taxable gain

    £12,000.00

  • Annual exemption used

    £3,000.00

  • Losses used

    £0.00

  • Capital Gains Tax

    £2,160.00

  • Effective CGT rate

    18.0%

Specialist reliefs excludedPrivate Residence Relief, Lettings Relief, Business Asset Disposal Relief, Investors’ Relief, share pooling and similar rules are not modelled.
Baseline insightAny baseline CGT comparison ignores package-level losses and the Annual Exempt Amount for illustration only.
Estimated effect of the Annual Exempt Amount and entered losses£540.00 lower Capital Gains Tax than a same-engine baseline without package-level losses or the Annual Exempt Amount. Baseline Capital Gains Tax is recalculated on the same disposals and estimated taxable income, with no package-level current-year losses, no brought-forward losses, and no Annual Exempt Amount. It is an estimate for comparison only, not tax advice. This does not imply that incurring expenditure solely to reduce tax is economically beneficial.

Disposal summary

Asset type

Shares

Acquisition date

1 June 2024

Disposal date

1 August 2026

Tax year

2026/27

Sale proceeds

£35,000.00

Total allowable costs

£20,000.00

Capital gain

£15,000.00

Post-tax cash from a disposal depends on more than Capital Gains Tax. See Capital Gains Tax Explained.

How a capital gain is calculated

Sale proceeds less allowable selling costs give net disposal proceeds. Subtract acquisition cost, acquisition costs and qualifying improvement expenditure to estimate the capital gain or capital loss. See Capital Gains Tax Explained.

Allowable acquisition and selling costs

Incidental costs of acquisition and disposal can reduce a gain where allowable. Ordinary ownership and maintenance costs are not entered here automatically.

Annual Exempt Amount

The Annual Exempt Amount for the tax year matching the disposal date can reduce remaining gains after losses. It cannot create or increase a capital loss.

Capital losses

Current-year losses and unused brought-forward losses can reduce net gains. Unused brought-forward losses may remain. Read Capital Losses for the wider rules.

Interaction with taxable income

Estimated taxable income excluding the gain is used only to size the unused UK basic-rate band. There is no separate third ordinary CGT rate for additional-rate taxpayers. The Income Tax Calculator can help estimate other taxable income for that input.

Shares versus residential property

Residential property and other assets can use different rate pairs. Property-specific reliefs such as Private Residence Relief are not modelled yet. See Capital Gains on Property.

2024/25 mid-year rate changes

Within 2024/25, some rates changed from 30 October 2024. The calculator selects the correct segment from the disposal date and shows that segment in the result summary where relevant.

Improvement expenditure

Qualifying capital improvement expenditure can reduce a gain. Routine repairs are not automatically allowable, and eligibility is not independently assessed here.

Unsupported reliefs and special rules

Private Residence Relief, Lettings Relief, Business Asset Disposal Relief, Investors' Relief, EIS, SEIS, share pooling, same-day and bed-and-breakfast matching, trusts, companies and non-resident CGT are excluded from this estimate.

Reporting and payment limitations

This tool estimates Capital Gains Tax only. It does not calculate reporting or payment deadlines, file a return, or decide which property reporting route applies. Residential property disposals can have different reporting rules from other assets — confirm the current GOV.UK guidance for your completion date. ISA wrappers can change whether a gain arises — see the ISA Guide.

Frequently asked questions

How is Capital Gains Tax calculated?

Northline starts from sale proceeds and subtracts allowable costs to estimate a capital gain or loss. It then applies losses, the Annual Exempt Amount and CGT rates based on the disposal date and asset type.

What costs can reduce a capital gain?

Allowable incidental acquisition and disposal costs, and qualifying improvement expenditure, can reduce a gain. Ordinary ownership and maintenance costs are not automatically allowable.

How does taxable income affect CGT?

Estimated taxable income excluding the gain is used only to size the unused UK basic-rate band. That band decides how much of the taxable gain is charged at the basic CGT rate before any remainder is charged at the higher rate.

Can I use capital losses?

Yes. Current-year allowable losses and unused brought-forward losses can reduce net gains before the Annual Exempt Amount. Unused brought-forward losses may remain.

What is the Annual Exempt Amount?

The Annual Exempt Amount is the tax-free allowance for Capital Gains Tax in the relevant tax year. It is taken from the year overlay that matches the disposal date.

Are property and share gains taxed at different rates?

Residential property and other assets can have different CGT rate pairs depending on the tax year and date segment. The calculator uses the configured rates for the selected asset class and disposal date.

What changed on 30 October 2024?

Within 2024/25, some Capital Gains Tax rates changed from 30 October 2024. The calculator selects the pre- or post-30 October segment from the disposal date.

Can I claim improvement expenditure?

Qualifying capital improvement expenditure can reduce a gain. Routine repairs and maintenance are not automatically allowable, and this calculator does not independently assess eligibility.

Does this calculator include Private Residence Relief?

No. Private Residence Relief, Lettings Relief and several other reliefs are listed as coming soon and are excluded from the current estimate.

Does this calculator handle share pooling?

No. Share pooling, Section 104 holdings, the same-day rule and the bed-and-breakfast rule are not modelled in this version.

Is a capital loss automatically reported to HMRC?

No. If the disposal creates a capital loss, the calculator shows the loss for planning only. It does not report or claim the loss with HMRC.

Official sources

Figures are estimates and may differ from Self Assessment, property reporting tools or adviser software. This is not tax, legal or financial advice.

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