Calculation examples.

Matching rules (BUY / SELL)

For Capital Gains reporting purposes in the UK, disposing of an asset is matched against purchases to identify the relevant gain or loss. Matching logic is defined by HMRC, and must be applied in a specific order to identify which purchases (and their costs) should be used. The rules applicable to the majority of scenarios are:

1. Same day

   First, the sale is matched against any purchase of the same shares, of the same class, on the same date.

2. 30-day (bed & breakfast)

   Next, the remaining shares are matched against purchases of the same instrument in the following 30 days on a first-in, first-out (FIFO) basis.

3. Section 104 pool

   Anything still unmatched from the sale is matched against the average cost of your previous section 104 pool, of the same instrument.

4. Later purchases (short sale)

   Finally, if the sale was bigger than everything above, the rest is matched against later purchases of the same instrument, the earliest first. This is rare: see Example 4.

Notes: Disposals from employee share schemes, EIS/SEIS have specific rules, and are not currently supported by the calculator.

Example 1: Section 104 Pool matching.

Two purchases are made on 20th and 21st April 2024, followed by a sale on 22 August 2024. Both purchases pre-date the sale and form the Section 104 pool. Since there are no same-day purchases, nor any purchase in the following 30 days of the sale, the whole disposal is matched against the Section 104 pool built from the two previous purchases.

event,date,code,units,price,costs,stamp_duty
BUY,20/04/2024,AAA,1000,4.60,5.00,23
BUY,21/04/2024,AAA,2000,4.30,5.00,21.5
SELL,22/08/2024,AAA,2000,4.90,5.00,0

Example 2: Same day matching takes precedence over the Section 104 pool.

A single sale can match purchases across more than one rule if not completely matched by the first. Same day purchases (and sales) are aggregated into equivalent single-directional trades, which are first matched against each other.

500 shares are bought on 1st February 2024. Two more purchases of 100 shares and 50 shares, take place on 15 June 2024, the same day as a sale of 300 shares of the same investment. The matching rules are applied in order: the disposal is matched against both same-day purchases (150 shares combined) first. Since there are no other purchases in the following 30-day period, the remaining 150 sold shares are matched to the Section 104 pool containing the earlier February purchase. One disposal; two matches.

event,date,code,units,price,costs,stamp_duty
BUY,01/02/2024,BBB,500,4.00,5,0
BUY,15/06/2024,BBB,100,4.20,5,0
BUY,15/06/2024,BBB,50,4.30,5,0
SELL,15/06/2024,BBB,300,4.50,5,0

Example 3: The 30-day rule only looks forward, not backward. Matching chronologically.

500 shares are bought over two transactions in January and mid March, and occur prior to the sale of 400 shares on 29 March. The earlier purchases form the Section 104 pool.

150 shares are later bought on 10 April, and another 75 shares on 11 April the same year. Both later purchases are within 30 days of (and after) the sale date. As there are no same-date purchases to match against, the next rule to be applied is the 30-day (bed-and-breakfast) rule. Any purchases within 30 days of the sale are first matched against the later purchase(s), starting with the earliest future purchase chronologically, before any remaining shares are matched against the Section 104 pool. The 30-day rule matches the first 150 & 75 shares of those sold. The remaining 175 shares are then matched against the Section 104 pool. The sale is still treated as a single transaction, although matching is against multiple purchases.

Note: Although the sale falls at the very end of the 2023/24 tax year (ending 5 April) matching a purchase in the following tax year, 2024/25, the gain is reported in the 2023/24 tax year. The reporting year is always determined by the date of the sale, not the date of the matching purchase.

event,date,code,units,price,costs,stamp_duty
BUY,10/01/2024,CCC,300,4.00,5,0
BUY,15/03/2024,CCC,200,4.10,5,0
SELL,29/03/2024,CCC,400,4.50,5,0
BUY,10/04/2024,CCC,150,4.20,5,0
BUY,11/04/2024,CCC,75,4.25,5,0

Example 4: A sale bigger than the shares held is matched against later purchases.

2,500 shares are bought over three purchases in 2021 and 2022, costing £3,700 in total. On 14 March 2025, 3,000 shares are sold for £10,275. There is no purchase on the same day or in the following 30 days, so the Section 104 pool covers 2,500 of the shares sold: a gain of £4,862.50.

That leaves 500 shares sold that were never held. HMRC's fourth rule (TCGA92 s105(2)) matches them with the next purchase after the sale, the earliest first: 1,000 shares bought on 30 May 2025, 77 days later, for £3.50 each. The 500 matched shares cost £1,750 against proceeds of £1,712.50, a loss of £37.50. The other 500 shares of that purchase go into the Section 104 pool.

Note: both parts of the sale are reported in the 2024/25 tax year, the year of the sale, although the matching purchase is in 2025/26. A private investor cannot normally sell shares they do not hold, so the calculator shows a reminder whenever this rule is used: it usually means a purchase is missing from the data.

event,date,code,units,price,costs,stamp_duty
BUY,12/04/2021,DDD,1000,1.30,0,0
BUY,02/08/2021,DDD,1000,1.45,0,0
BUY,17/01/2022,DDD,500,1.90,0,0
SELL,14/03/2025,DDD,3000,3.425,0,0
BUY,30/05/2025,DDD,1000,3.50,0,0

Foreign currency

Capital gains must be calculated in pounds sterling, GBP. Where a holding is bought or sold in another currency, each leg must be converted to GBP at the exchange rate on the transaction date.

The conversion to GBP is applied before any matching. The calculator contains daily exchange rates for major currencies to convert foreign currency values to GBP automatically, unless a user-provided rate is supplied.

Where data contains foreign currency values, the 3 character ISO currency code should be indicated in either the optional price_currency or cost_currency column.

• GBP is assumed if there are blank or missing currencies, or if the currency column is not included.
• Each monetary value column has an associated currency column, allowing different currencies to be used for each value.

Refer to the downloaded dataset to see the fx rates implemented.

Example 1: A US share bought and sold in US dollars from a dollar-denominated account, with a sterling dealing fee.

10 shares are bought and later sold on Nasdaq, both trades priced in US dollars. Adding the currency code in the price_currency column will convert that trade's price to GBP using the relevant daily exchange rate.

The broker fee is in pounds, and without supplying an alternative currency via the cost_currency column, is treated as sterling by default.

event,date,code,units,price_currency,price,costs
BUY,11/04/2025,ZZZ,10,USD,150.00,10.00
SELL,25/02/2026,ZZZ,10,USD,160.00,10.00

Example 2: Shares quoted in pence, GBX.

A purchase and sale of shares in YYY are made and reported by the broker in GBX. The broker's fee is reported in GBP.

The calculator will automatically convert GBX prices to GBP, where the currency is appropriately labelled in the data. Since the costs are in GBP, the default currency, conversion is not necessary. Adding the cost_currency column is optional.

event,date,code,units,price_currency,price,cost_currency,costs
BUY,12/04/2023,YYY,1000,GBX,1050.50,GBP,10.00
SELL,20/01/2026,YYY,1000,GBX,1100.50,GBP,10.00

Example 3: Using an actual exchange rate.

A purchase of SSS shares is made in USD with a spot fx rate calculated by the broker. Later when a sale is made, the proceeds remain in the same currency, unconverted in a dollar account. The transaction's actual foreign exchange rate is used (instead of a daily rate) to calculate the purchase cost in GBP, while the daily rate is used to establish the sterling value of the disposal for capital gains purposes.

When the exchange rate used in a transaction is known, this should be used instead of the more generalised daily rate. This includes situations where the currency is not otherwise supported by the calculator.

The price_fxrate column is used to specify the exchange rate. Any other rows left blank will default to the calculator's daily exchange rate for the specified currency.

Note: If a user-provided rate is significantly different from the calculator's daily rate for the same currency, a warning will be displayed in the output, small differences are ignored. When providing a user rate, the currency code column must also be filled.

event,date,code,units,price_currency,price_fxrate,price,cost_currency,costs
BUY,04/03/2018,SSS,200,USD,1.3834,100.00,GBP,10.00
SELL,22/02/2026,SSS,200,USD,,160.00,GBP,10.00

Offshore reporting funds - Excess reportable income (ERI)

For offshore reporting funds (including both accumulation and distribution versions), fund income not wholly distributed is subject to Excess Reportable Income (ERI) treatment. This includes many popular ETFs, typically those domiciled in Ireland or Luxembourg.

ERI is calculated based on the fund's reporting date, and is taxable as income in the tax year of the fund's distribution date (which occurs strictly six months later). As a result of this timing difference between the two dates, reportable income and the effect on capital gains can fall into different tax years.

To include Excess Reportable Income in the gains calculation, obtain the ERI values from your fund manager or external data aggregator, such as KPMG's Reporting Funds website. Add one row for each ERI entry per fund, per reporting period. Date this row using the fund's reporting date and input the per-unit ERI amount in the price column. The distribution date is calculated automatically from the reporting date.

The calculator treats this ERI entry in two ways, calculating your taxable income on the fund's distribution date from the ERI per share value and holding size. The allowable cost of your Section 104 pool is also increased by the ERI per share value multiplied by the units you held on the reporting date, reducing your capital gain on eventual disposal.

Because ERI is calculated against the holding on the fund's annual reporting date, add an ERI row for each offshore reporting fund annually, while held, to ensure all excess income is calculated for each tax year. Any ERI rows added for a fund not held on the reporting date are ignored and will not affect your capital gains or income tax calculation.

Example 1: Adding Excess Reportable Income (per share) values for a reporting fund.

500 units of a reporting fund are bought in March 2023. Each year, the fund declares its excess reportable income per share, in this case yearly on 30 November - its reporting period end date. The ERI is included as ERI event rows, throughout the investment's holding period. The reported ERI is added to the pool's cost base in relation to the shares held on each reporting date, and the equivalent taxable income identified and allocated to its applicable tax year. A further 400 units are bought in March 2024, and the holding is sold in two parts, in June 2025 and April 2026.

event,date,code,units,price,costs,stamp_duty
BUY,15/03/2023,GGG,500,1.00,0,0
ERI,30/11/2023,GGG,,0.0415,,
BUY,12/03/2024,GGG,400,1.05,0,0
ERI,30/11/2024,GGG,,0.0450,,
SELL,01/06/2025,GGG,200,0.95,0,0
ERI,30/11/2025,GGG,,0.0555,,
SELL,01/04/2026,GGG,700,1.15,0,0

Example 2: A fund reporting its excess reportable income in euros.

Many reporting funds are domiciled in Ireland or Luxembourg and declare their excess reportable income in the fund's own currency, even where the units themselves can be bought and sold in sterling.

The ERI rows record the reported value and currency, which is converted on each date into GBP prior to determining the taxable income.

event,date,code,units,price_currency,price,costs,stamp_duty
BUY,15/03/2023,GGG,500,,1.00,0,0
ERI,30/11/2023,GGG,,EUR,0.0415,,
BUY,12/03/2024,GGG,400,,1.05,0,0
ERI,30/11/2024,GGG,,EUR,0.0450,,
SELL,01/06/2025,GGG,200,,0.95,0,0
ERI,30/11/2025,GGG,,EUR,0.0555,,
SELL,01/04/2026,GGG,700,,1.15,0,0

UK domiciled funds (EQUALISATION / NOTIONAL)

Notional distributions and equalisation apply differently depending on the share class of the UK-domiciled fund. Equalisation affects both accumulation and distribution funds, while notional distributions apply exclusively to accumulation funds.

Accumulation units of a UK-domiciled fund reinvest income instead of paying it out. That reinvested income is still taxable as income. The reported income value increases the fund's allowable cost, reducing the gain when you sell.

Distribution units (also known as income units) do not have notional distributions in addition to any actual distributions. By law, UK-domiciled distribution funds are required to distribute 100% of the income that accrues over their accounting period, and so there is no additional notional distribution to report.

Your statement usually shows the notional distribution and, separately, its equalisation value. Use the income data for a NOTIONAL row and the equalisation data as an EQUALISATION row.

When recording an accumulation fund's notional distribution as a NOTIONAL row, use the distribution date as the row date and put the total reinvested amount for your holding in the price column (units are left blank; the calculator spreads the amount over the units held). The calculator reports it as income in the distribution date's tax year, and increases the Section 104 pool cost, reducing the capital gain by the same amount.

Equalisation applies to units bought part-way through a distribution period. The first distribution on those units includes a return of part of your own initial capital. This distribution is not income, but instead is a return of base cost, which reduces the pool cost. Record it with an EQUALISATION row, put the total amount for your equalisation in the price column, and leave the units column blank.

Note: Offshore reporting funds are different. Their retained income is Excess Reportable Income (ERI), not a Notional distribution. Use ERI for Offshore reporting funds and NOTIONAL for UK-domiciled accumulation funds; do not enter both for the same holding.

Example: A UK-domiciled Accumulation fund purchase, with a later equalisation rebate and notional distribution

100 units of a UK-domiciled Accumulation fund are bought in January 2022. On its 30 June 2022 distribution date your statement shows a £30 notional distribution, of which £12 is equalisation, so £18 is Notional income (reportable as income, but adding £18 to the pool cost, reducing a future gain by the same amount), and £12 is a return of capital (reducing the pool's cost by £12).

event,date,code,units,price,costs,stamp_duty
BUY,10/01/2022,HHH,100,10.00,0,0
NOTIONAL,30/06/2022,HHH,,18.00,,
EQUALISATION,30/06/2022,HHH,,12.00,,
SELL,01/02/2023,HHH,100,12.00,0,0

Rights issues (RIGHTS / RIGHTS_SALE)

A rights issue offers you new shares pro rata to your holding, at a set price (e.g. 1-for-4 at 250p). You can participate in the rights (in part or in full) by paying the subscription price and receiving new shares, or sell the rights nil-paid. If you do nothing, the rights either lapse and you receive no payment, or the rights are automatically sold and you receive the nil-paid value.

Your response to the rights determines how to record that in the calculator:

Notes: the RIGHTS_SALE treatment assumes the proceeds are 'small'. HMRC accepts up to 5% of the holding's value, or £3,000, whichever is greater (CG57835). Larger nil-paid sales are a part-disposal needing the holding's market value, which this calculator does not support. Check before relying on it. Proceeds greater than the pool's cost at that date also need the part-disposal treatment. The calculator rejects with an error rather than computing a wrong figure.

Example 1: Rights taken up, paying the subscription price.

A 1-for-16 rights issue at 150p on your existing 4,000 share holding in DDD is fully taken up on 15/06/2023, giving you 250 new shares. The RIGHTS row records the 250 new shares at their 150p subscription price. The new shares join the pool at their subscription cost and are treated as having the same acquisition date as the underlying shares.

event,date,code,units,price,costs,stamp_duty
BUY,12/07/2021,DDD,4000,1.20,0,0
RIGHTS,15/06/2023,DDD,250,1.50,,
SELL,03/03/2024,DDD,2000,2.10,5,0

Example 2: Rights sold nil-paid.

A rights issue is announced, but the rights are sold nil-paid in full for £180 on 15/06/2023.

The RIGHTS_SALE row leaves units blank and puts the total proceeds in the price column. The proceeds are a small capital distribution under s122(2): they are deducted from your pool cost base, so no gain arises at that point; instead, the gain on the eventual sale increases. Fractional-entitlement payments are treated the same way.

event,date,code,units,price,costs,stamp_duty
BUY,12/07/2021,EEE,2000,1.20,0,0
RIGHTS_SALE,15/06/2023,EEE,,180,,
SELL,03/03/2024,EEE,2000,2.10,5,0

Stock splits, consolidations and bonus issues (REORG)

These are all reorganisations of share capital and HMRC treats them identically: no disposal, no acquisition. Your holding keeps its total cost and original acquisition date; but the share count changes, affecting the average cost per share.

Record one REORG row per event, dated on the event date, with the ratio in the price column and units left blank. The calculator restates your earlier trades in that stock into the new share basis, so gains and holding periods stay correct.

The ratio is simply shares held after ÷ shares held before. For a bonus issue the 'after' count includes the free shares:

Same-day ordering: the reorganisation is treated as happening before any other activity on its own date (the market's ex-date convention). So a purchase or sale on the same day as the REORG row is already recorded in the post-event share basis and is not itself restated. Only trades dated strictly before the event are restated.

Rights issues are different: they involve payment. See Rights issues above.

Example: 50 FFF shares bought in February 2020 are split 5-for-1 that August (ratio 5.0). The pool is restated to 250 shares at the same total cost, before 250 shares are eventually sold in 2024.

event,date,code,units,price,costs,stamp_duty
BUY,02/02/2020,FFF,50,100.00,0,0
REORG,31/08/2020,FFF,,5.0,,
SELL,05/03/2024,FFF,250,21.00,0,0

Losses from elsewhere (LOSS)

Use a LOSS row to add capital losses calculated outside this calculator, such as losses carried forward from previous years or losses from untracked assets (e.g. a second property, Business Asset Disposals, or external accounts). Enter the loss amount as a positive number in the price column, leave units blank, and optionally use the code column to add a custom label so you can recognise the entry later (e.g. 'Property Capital Loss').

Since the loss is added manually by the user, it is labelled user-reported: in the calculation text, the exported files and the HMRC boxes tab. You remain responsible for it, and for having claimed the loss properly: a claim must normally be made within four years of the end of the tax year in which the loss arose (TCGA92 s16(2A)).

Why the date matters. It decides which of two different HMRC rules applies:

• Losses arising in the current year must be set against that year's gains in full first, even where doing so reduces your net gain below your annual exempt amount (AEA), meaning part of the AEA is wasted (TCGA92 s1K(4)(a)).
• Where the loss remains outstanding after offsetting any gains in that year, the unused loss can be carried forward. That brought-forward loss can be used to reduce gains down to the annual exempt amount in future years, with the remainder carried forward again to be used against other future years' gains (TCGA92 s1K(4)(b)).

If you are entering losses brought forward from earlier years, date them in the tax year they arose, not in the year you are claiming them, to avoid incorrect treatment with the annual exempt amount.

Example 1: £5,000 of losses brought forward from 2023-24, against a £7,000 gain in 2025-26

The loss is dated in the year it arose, before the 2025-26 tax year, so it becomes a carried-forward loss. In 2025-26 the £7,000 gain is first reduced by the £3,000 annual exemption, and only the remaining £4,000 gain needs to be covered by the brought-forward loss, leaving £1,000 of loss to carry forward to future years' gains.

event,date,code,units,price,costs,stamp_duty
LOSS,15/09/2023,PRIOR-YEAR-UNRELIEVED_LOSS,,5000.00,,
BUY,10/01/2026,JJJ,1000,10.00,0,0
SELL,01/02/2026,JJJ,1000,17.00,0,0

Example 2: a £5,000 loss arising in the same year as a £7,000 gain (2024-25)

In this case, the loss arose in 2024-25 from a buy-to-let property disposal, in the same year as the investment gains. That loss comes off the year's gains first, before the annual exemption is applied, and in full: the £7,000 gain drops to £2,000, and only then does the exemption apply. Just £2,000 of the £3,000 allowance is needed to clear the remaining chargeable gains. The other £1,000 of exemption is wasted, with none of the loss surviving to carry forward to future years.

event,date,code,units,price,costs,stamp_duty
LOSS,15/09/2024,BTL-PROPERTY,,5000.00,,
BUY,10/01/2025,KKK,1000,10.00,0,0
SELL,01/02/2025,KKK,1000,17.00,0,0

Spouse and civil-partner transfers (TRANSFER)

A gift of shares to your spouse or civil partner is a disposal at no gain, no loss (TCGA92 s58): you pay no tax, and your spouse inherits your cost. Record one TRANSFER row per gift: units transferred, price left blank (the deemed proceeds equal the cost, so there is nothing to enter). It is matched through the normal same-day, 30-day, Section 104 and later-purchase rules, and the matched cost is reported as passed to your spouse.

A market sale and a transfer of the same stock on the same day are fully supported: HMRC pools them into one disposal (s105) and the calculator apportions the matched cost pro rata between your taxable sale and the transfer. The Spouse transfers results tab lists the cost passed on and generates ready-to-paste BUY rows for your spouse's own file.

Notes: a transfer can never create a loss; the loss potential travels with the cost. No gain, no loss only applies while you are married or in a civil partnership and living together (not separated). A repurchase by your spouse is not caught by your 30-day rule. There are special rules for transfers in the year of divorce, which are not supported by the calculator.

Example 1: Shares transferred to spouse.

Of a 2,500 share LLL holding, 2,000 are transferred to the spouse. The matching rules identify the average cost which is passed to the spouse as a no gain/no loss TRANSFER.

event,date,code,units,price,costs,stamp_duty
BUY,12/07/2021,LLL,1000,1.20,0,0
BUY,04/10/2022,LLL,1500,1.40,0,0
TRANSFER,03/03/2024,LLL,2000,,,

Example 2: A sale and transfer on the same day.

Of a 4,000 share MMM holding, 3,000 are sold and 1,000 are transferred to a spouse on the same day. HMRC pools the sale and the transfer together (s105) and the matched cost is split pro rata between the taxable SELL and the no gain/no loss TRANSFER.

event,date,code,units,price,costs,stamp_duty
BUY,12/07/2021,MMM,4000,1.20,0,0
SELL,03/03/2024,MMM,3000,2.10,5,0
TRANSFER,03/03/2024,MMM,1000,,,

Calculation precision (18 decimal places) & Crypto Currencies

Fractional disposals are reported at fractions of a unit, and Cryptocurrency quantities are held up to 18 decimal places. For example, 1 ETH is 1,000,000,000,000,000,000 wei, and an exchange will report your holding to the last wei. Fractional shares raise the same issue on a smaller scale, as platforms selling part shares often quote six or eight decimal places.

The calculator processes your unit quantity exactly as entered. It does not round units, as rounding can adversely change the result. The Section 104 pool is a running balance, so even a small rounding difference on each transaction can build up over time, meaning a fully sold holding may otherwise still appear to be open.

Money is handled differently. Cash figures are kept at high precision through matching, and rounded only for presentation; to the penny at transaction level and to the pound in the summary. See HMRC guidance , CG14200.

Example 1: Three purchases that add up to exactly ten ETH.

Two transactions of 3.333333333333333333 ETH and a third of 3.333333333333333334 ETH are purchased, totalling exactly 10.000000000000000000 ETH. The whole holding is sold on 14 February 2024. The sale of 10 ETH closes the position, leaving a holding of zero. The pool cost is £21,000.00 and the proceeds are £30,000.00, giving a gain of £9,000.00.

Early rounding of holdings would have lost precision, stopping the final sale units from matching the calculated rounded holding. For example, rounding of the 3 trades above to 8 decimal places would round each to 3.33333333, totalling 9.99999999 ETH, rather than the 10 ETH later being sold.

event,date,code,units,price,costs
BUY,12/05/2023,ETH,3.333333333333333333,1800.00,0
BUY,03/08/2023,ETH,3.333333333333333333,2100.00,0
BUY,21/11/2023,ETH,3.333333333333333334,2400.00,0
SELL,14/02/2024,ETH,10.000000000000000000,3000.00,0

Example 2: The same purchases, with one wei held back.

The sale is one wei short of the whole holding, so the pool is left holding exactly 0.000000000000000001 ETH. The gain is unchanged at £9,000.00. A single wei has a pool cost far less than a penny, as its value is based on its purchase price for 10 ETH. The cost displays as £0.00, but the position is still recorded as open.

event,date,code,units,price,costs
BUY,12/05/2023,ETH,3.333333333333333333,1800.00,0
BUY,03/08/2023,ETH,3.333333333333333333,2100.00,0
BUY,21/11/2023,ETH,3.333333333333333334,2400.00,0
SELL,14/02/2024,ETH,9.999999999999999999,3000.00,0

The prices here are round numbers chosen to make the arithmetic checkable by eye, not market rates for the dates shown.

Pre-1982 acquisitions (1982 rebasing)

Shares you already held on 31 March 1982 should be rebased for CGT purposes (TCGA92 s35): your original purchase cost is replaced with the asset's market value on 31 March 1982. That date becomes your acquisition date for CGT purposes. Use this rebased value in the calculator, with the rebasing date of 31 March 1982.

Example: Adding pre 31 March 1982 acquisitions

1,000 NNN shares were bought on 15 June 1979 for 100p each. Their market value on 31 March 1982 was later assessed to be 150p per share, so that value forms the rebased cost as at the 31 March 1982: the input file records a single BUY dated 31/03/1982 at 150p, before the holding is eventually sold in 2024.

event,date,code,units,price,costs,stamp_duty
BUY,31/03/1982,NNN,1000,1.50,0,0
SELL,10/09/2024,NNN,1000,5.00,5,0

Note: Only enter the rebased 31/03/1982 value and date, not the original 1979 purchase price.