Guide
Can you complete your sale before 6 April 2027? A checklist
Updated
Complete a £1,000,000 share sale by 5 April 2027 and Capital Gains Tax is £179,460; on 6 April, £209,280. That £29,820 is the cost of the deadline slipping.
Talk to a specialist Sale price, relief, Capital Gains Tax and what reaches your account, whether you complete by 5 April 2027 or after.
Email me this result
We will send you these figures and a link back to them. One email, nothing else unless you tick the box.
How this calculator works
- Business Asset Disposal Relief charges 18% on all gains on qualifying assets disposed of from 6 April 2026. It was 14% between 6 April 2025 and 5 April 2026, and 10% on or before 5 April 2025.
- If your completion date falls in an earlier window, the older rate applies (gov.uk: Business Asset Disposal Relief, and HMRC rates and allowances, updated 13 April 2026).
- The relief is capped across your lifetime, not per disposal: £1,000,000 of gains for a disposal before 6 April 2027. That limit has applied to qualifying disposals on or after 11 March 2020 (gov.uk, HMRC Capital Gains Manual CG64125).
- Budget 2026 cuts it to £500,000 for qualifying disposals made on or after 6 April 2027, at the same 18% rate. Source: HMRC tax information and impact note, 29 October 2026.
- The cut is in the Finance Bill 2026: until Royal Assent it is announced policy, not law. Enter what you have already used.
- Gains above the relief are taxed here at 24%, the higher or additional rate taxpayer's rate. Budget 2026's rates table shows 18% and 24%, and the £3,000 annual exempt amount, unchanged for 2027 to 2028 (Budget 2026, Annex A: rates and allowances).
- A basic rate taxpayer pays 18% on the part of the gain inside their unused basic rate band. So this calculator overstates the tax for someone with little other income (gov.uk: work out your tax).
- The annual exempt amount is £3,000 for 2026/27, unchanged from 2025/26 and 2024/25. As HMRC directs, it is applied to the gains charged at the highest rate first. So it comes off the 24% slice before the 18% slice (HMRC rates and allowances).
- Qualifying for the relief on a share sale broadly requires three things, for at least two years to the date of disposal. You were an officer or employee of the company. It was a trading company or the holding company of a trading group.
- And you held at least 5% of the ordinary shares and voting rights. You were entitled to at least 5% of distributable profits and assets on winding up, or of the proceeds on a sale (gov.uk eligibility, HMRC CG63975, TCGA92/S169I).
- Sole traders and partners qualify on a different two-year test. The toggle takes your word for it; HMRC will not.
- Fees are treated as incidental costs of disposal: they reduce the chargeable gain and the cash you keep. Base cost is what you paid for the shares, which for founders' shares subscribed at par is usually negligible.
- Founders' Relief is computed on the consultation draft, which closes at 11:59pm on 30 November 2026 (HM Treasury technical consultation). The draft charges 10% on qualifying share disposals from 6 April 2027, up to a lifetime limit of £10 million (HMRC tax information and impact note).
- Any Business Asset Disposal Relief or Investors' Relief claimed from 6 April 2027 reduces that limit (Annex A). This calculator assumes none has been claimed, taxes any gain above £10 million at 24%, and applies the relief only when you answer Yes. The conditions can change before the Finance Bill 2026/27 is passed.
- An Employee Ownership Trust sale: from 26 November 2025, 50% of the gain on a qualifying disposal to the trustees is chargeable. The other 50% is held over to the trust. Business Asset Disposal Relief and Investors' Relief are not available on it (HMRC tax information and impact note, helpsheet HS277).
- The chargeable half is taxed here at 24% after the annual exempt amount. The Founders' Relief consultation draft does not say whether that relief can apply to a sale to a trust, so this calculator never applies it there.
- Which date counts. Under a contract the disposal happens when the contract is made, not when the shares are transferred. Under a conditional contract it happens when the condition is satisfied (Taxation of Chargeable Gains Act 1992, section 28).
- Budget 2026 adds anti-forestalling rules for unconditional contracts entered into before 6 April 2027 and completed on or after it. The £500,000 limit applies unless the parties show they did not contract for the timing rule's tax advantage.
- Connected parties must show the contract was wholly commercial. A statement is needed where the gain exceeds £100,000 (HMRC). The calculator's completion date stands for the date of disposal under those rules.
- Not modelled, and each can move the answer materially: earn-outs and deferred consideration, share-for-share exchanges and loan notes, EMI and other option exercises, and capital losses brought forward.
- Nor are Investors' Relief, disposals by trustees or personal representatives, multiple shareholders with different holdings, or anyone not resident in the UK for tax. Take advice before relying on a figure from any calculator, including this one.
What changes on 6 April 2027
Business Asset Disposal Relief's lifetime limit falls from £1 million to £500,000 for qualifying disposals made on or after 6 April 2027. The rate on relieved gains stays 18% (HMRC tax information and impact note).
On a gain of £500,000 or less nothing changes. Above it, every pound between £500,000 and £1,000,000 moves from 18% to 24% for a higher rate taxpayer. The cut is in the Finance Bill 2026 and becomes law at Royal Assent.
The date HMRC uses
Under a contract the disposal happens when the contract is made, not when the shares are transferred. Under a conditional contract it happens when the condition is satisfied (Taxation of Chargeable Gains Act 1992, section 28). A sale conditional on a lender's consent, a regulator's change-of-control approval or a shareholder vote dates from that day.
Signing before 6 April and completing after
Budget 2026 adds anti-forestalling rules for unconditional contracts entered into before 6 April 2027 that complete on or after it. Their gains fall under the £500,000 limit unless the parties show they did not enter the contract for the timing rule's tax advantage.
Connected parties must instead show the contract was for wholly commercial reasons. Relying on that needs a statement where the gain exceeds £100,000 (HMRC). Signing early and completing late is not a safe way to keep the £1,000,000 limit.
The checklist
- Run your own figures in the calculator with the completion date switched both ways, so you know what slipping costs before you decide how hard to push.
- Check you meet Business Asset Disposal Relief's conditions for the two years up to the contract date: an officer or employee, a trading company, at least 5% of the shares, votes and economic rights.
- Agree heads of terms with a buyer who can fund the deal, and set the timetable back from 5 April 2027 rather than forward from today.
- List every condition the contract will carry (lender consent, regulatory approval, landlord consent, shareholder approval) and when each can be met: under a conditional contract the tax date is the day the last one is satisfied.
- Start due diligence early: the data room, the accounts, the contracts the buyer will read, and anything that needs fixing before a buyer finds it.
- Ask your adviser whether any deferred or contingent consideration changes the picture: the calculator does not model an earn-out.
- If the date cannot be met, price it: compare the cost from the calculator with what the buyer will pay for a later completion, and ask whether Founders' Relief could apply instead.
The £500,000 limit is announced at Budget 2026 and is not yet law; the forestalling rules are described in HMRC's impact note, not yet in legislation. This page will be re-read when the Finance Bill 2026 is published and again at Royal Assent. It is not tax advice.