This is a freeview 'At a glance' guide to how to compute a capital gain or loss for individuals and trustees.

How do you calculate a capital gain or loss? What costs are deductible? How can losses be utilised against capital gains?

At a glance

Capital gains and losses are calculated after deducting:

s.38 TCGA 1992 deals with what costs are deductible for CGT. See CGT: Deductible expenditure    

The rate of Capital Gains Tax that applies will be either:

depending on the taxpayer's other income levels and whether any CGT reliefs are available to reduce the rate of tax such as:

There are special rules for part disposals.

The gains on disposal of some assets are subject to Income Tax rates. See Overview and examples.

Care should be taken to consider whether the disposal of a particular asset is subject to CGT as some are exempt.

There may be special rules which need to be applied in particular cases, for example in relation to Chattels.  

Overview and examples

See Proforma computations tab for the layout of a standard CGT computation.

Step 1: disposal proceeds

These are the total sales proceeds received including any deferred ascertainable consideration.

See Selling the business: Deferred consideration and earn-outs           

Step 2: deduct selling costs   

These will include estate agents, legal and valuation fees and non-recoverable VAT. 

If the property is being gifted there may also be fees incurred for valuation or legal work to transfer title.     

See CGT: Deductible expenditure                                

Step 3: deduct acquisition costs (base cost)

In most cases, this will be the price originally paid for the asset.

The base cost can also include the costs of creating an asset where one has been created, e.g. copyright.

Where there is a part disposal only a proportion of the original cost will be allowable. This is calculated by the formula:


   A + B

Where A = the disposal consideration, and B = the value of the part retained at the time of the part-disposal.

Where there has been a previous part disposal any proportion of the original cost already taken into account will not be available for a deduction on later disposals.

Where the asset disposed is a wasting asset, there may be a restriction to the costs that are allowable. 

In Anthony Hardy v HMRC (2015) TC04444, a taxpayer failed to claim Capital Gains Tax (CGT) loss relief on a lost property deposit. This decision has since been confirmed by the Upper Tribunal who found that:

The decisions in this case confirm the well-established principle that lost deposits are not allowable for CGT purposes.

See CGT: deductible expenditure                                                                                  

Step 4: deduct enhancement expenditure

This is the cost of capital expenditure incurred on the asset since acquisition:

E.g. The cost of successful planning applications that add value, structural improvements and pre-sale renovations, such as re-wiring, re-roofing, re-decorating, renovations between tenancies which were disallowed for Income Tax.

Capital expenditure that has added no value to the asset, such as the costs of failed planning applications are non-tax deductible.

Expenses that are allowable for Income Tax are not deductible for CGT. For example, expenses of property letting which are an allowable deduction from rental profits such as general repairs and maintenance and insurance are not CGT deductible.     

Enhancement expenditure may be subject to restrictions, for example where there is a part disposal (see above).     

Step 5: deduct costs of purchase          

If the property was acquired as a gift there may not be any purchase costs.

Purchase expenditure may be subject to restrictions, for example where there is a part disposal (see above). 

See CGT: Deductible expenditure                 

Step 6: deduct current year capital losses

Allowable capital losses which occur in the same tax year must be offset against a gain made in the same year before other losses, capital losses brought forward, or the CGT annual exemption may be utilised.

A loss will not be allowable if it is a 'Clogged' loss. A loss is clogged if it is a capital loss made on a disposal of an asset to a Connected person. These types of losses may only be used against gains accruing on the disposal of an asset to the same person whilst the parties are still connected.         

NOTE: For disposals on or after 6 April 2020:

See CGT: Reporting, How to report CGT?                                        

Step 7: deduct surplus Income Tax losses eligible for sideways loss relief claim

An unrelieved loss of a trade, profession or vocation may also be used to offset capital gains. This is subject to restrictions:

However, the Sideways loss relief cap does not apply to relief against capital gains.                         

Step 8: deduct Annual Exemption

Step 9: deduct capital losses brought forward

Brought forward capital losses do not have to be used before the CGT annual exemption. A partial claim to relief can be made, to avoid wasting the AE with the remaining losses carried forward to future years.

Step 10: apply eligible reliefs

These might include:

Some reliefs may apply before steps 6 to 9. It is necessary to consider at which stage of the gain calculation reach relief applies. 

Step 11: determine the rate of tax

Gains on residential property are subject to tax at 18% or 28% depending on the taxpayer’s other income levels. Higher and additional rate taxpayers pay CGT at 28%.

Gains on other assets are subject to tax at 10% or 20% depending on the taxpayer’s other income levels. Higher and additional rate taxpayers pay CGT on these assets at 20%.

Some reliefs impact the rate of CGT payable where higher rates may otherwise apply, for example: 

There are a few types of asset where, although referred to as chargeable gains or chargeable events, Income Tax rates apply. These include:

Step 12: ensure applicable reliefs are claimed within the relevant time limits

Most CGT reliefs have to be claimed on the Self Assessment return and the deadline is therefore the deadline for amending the return that is, 12 months from 31 January after the end of the relevant tax year. For a disposal in 2021-22 the deadline is 31 January 2024.

The exceptions are:

Proforma computations

This is a proforma computation that includes potential deductions and reliefs, some of which may not be relevant to your case. It should be used in conjunction with the step-by-step notes on the Overview and examples tab.


Step 1: Disposal proceeds                                                                                              X

Step 2: Deduct selling costs                                                                                          (X)


Step 3: Deduct acquisition cost                                                                                     (X)

Step 4: Deduct enhancement expenditure                                                                    (X)

Step 5: Deduct purchase costs                                                                                     (X)

Net gain/(loss)                                                                                                                X

Step 6: Deduct current year capital losses                                                                   (X)

Step 7: Deduct surplus Income Tax losses: sideways loss relief claim                         (X)

Gain before Annual Exemption                                                                                      X

Step 8: Deduct Annual Exemption                                                                                (X)

Gain after Annual Exemption                                                                                         X

Step 9: Deduct capital losses brought forward                                                             (X)

Step 10: Apply eligible reliefs                                                                                        (X)

Taxable gain                                                                                                                  X  

Step 11: Determine the rate of tax*

Apply to net taxable gain after Annual Exemption, capital losses and reliefs

Tax due                                                                                                                         X

Step 12: Ensure applicable reliefs are claimed within the relevant time limits.

*Residential property is taxed at 18% (basic rate band) or 28%. Other assets are taxed at 10% (basic rate) or 20%. Reliefs such as Business Asset Disposal Relief and Investors' Relief apply a 10% flat rate of CGT to qualifying gains.  

See CGT rates and allowances

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