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UK EIS / SEIS Calculator

Free UK EIS / SEIS investor relief calculator. 30 percent (EIS) or 50 percent (SEIS) income tax relief plus loss relief plus CGT exemption.

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UK EIS / SEIS investor relief.

Income tax relief

Effective at-risk capital

Loss relief on full failure

Your breakdown

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How the schemes turn risk into a smaller bet

The Enterprise Investment Scheme and its seed cousin SEIS exist because early-stage companies are starved of capital and most of them fail. The government's answer is to use the tax system to cushion the downside so investors will take the chance. The headline is income tax relief, 30 percent of your subscription for EIS and a generous 50 percent for SEIS, claimed in the year you invest. This calculator strips that relief out of your investment to show what is genuinely at risk, then layers on loss relief to reveal your true worst case if the company goes to zero.

The reliefs are deliberately weighted towards SEIS because it funds the very earliest, riskiest companies, often pre-revenue. EIS targets slightly more established but still young firms. Both sit alongside other benefits the calculator references in its notes: gains on shares held at least three years are free of capital gains tax, and on death the shares can fall outside your estate for inheritance tax under business relief, subject to the rules.

A £50,000 SEIS subscription, downside and all

Picture a 45 percent additional-rate taxpayer putting £50,000 into a qualifying SEIS company. The 50 percent relief returns £25,000 against their income tax bill, so the capital genuinely exposed is only £25,000. Now assume the worst and the company fails completely. Loss relief lets them set the at-risk £25,000 against income at their 45 percent marginal rate, clawing back a further £11,250.

So a £50,000 punt has a genuine downside of £13,750, around 27 pence in the pound. The bar chart lines up the headline investment against what the taxpayer can actually lose once both reliefs have done their work.

The rules that protect the relief

The reliefs are valuable, which is why HMRC guards them tightly. You must hold the shares for at least three years; sell early and the income tax relief is clawed back. You cannot be connected to the company, meaning you and your associates cannot hold more than 30 percent of it, and you generally cannot be a paid employee, though SEIS does allow you to be a director. The company itself has to qualify on age, size, and trade, and it must use the money for a genuine growth trade rather than, say, property or financial activities. Always wait for the EIS3 or SEIS3 certificate before claiming; without it HMRC will not give you the relief.

Can I carry the relief back to last year?

Yes, and this is one of the most useful and overlooked features. Both EIS and SEIS let you elect to treat the subscription as if made in the previous tax year, so you can claim the income tax relief against the prior year's bill. That is handy if you had a bigger tax liability last year, or if you have already used your relief capacity this year.

Who these schemes really suit

The honest answer is that EIS and SEIS are for higher and additional-rate taxpayers who can afford to lose the money. The income tax relief is only as valuable as the tax bill it offsets, so a basic-rate taxpayer with little liability extracts far less from the same investment, which is why this calculator asks for your marginal rate. Just as important, these are genuinely high-risk holdings in young, illiquid companies, and the tax reliefs cushion losses rather than prevent them. Treat the relief as a discount on a speculative bet, not as a reason to make a bet you would otherwise avoid. A sensible approach is to spread subscriptions across several companies rather than backing one, since the whole design assumes some will fail.

What is SEIS reinvestment relief on a gain?

If you have a capital gain and reinvest the proceeds into SEIS shares, you can exempt half of that gain from capital gains tax, on top of the 50 percent income tax relief. Stacked together, the reliefs on a successful SEIS investment can be remarkably generous, which is precisely why the annual limits, £200,000 for SEIS and £1 million for EIS, exist to cap them.

Frequently asked questions

EIS vs SEIS limits?
EIS: £1M/year invested for 30 percent income tax relief (£2M for knowledge-intensive). SEIS: £200K/year for 50 percent relief, but invests in even earlier-stage companies. SEIS plus EIS can stack with the same investor across different companies.
How long must I hold EIS or SEIS shares to keep the relief?
You must hold the shares for a minimum of three years from the date of issue or from when the company started trading, whichever is later. Disposing of the shares before that point triggers a clawback of the income tax relief you claimed. The three-year holding period also applies to the CGT exemption on any gain you make.
Can I claim EIS or SEIS relief if the company has not yet issued an EIS3 or SEIS3 certificate?
No. HMRC requires the company to obtain advance assurance and then issue an EIS3 (or SEIS3) certificate before investors can make a relief claim on their Self Assessment return. You can invest early, but you must wait for the certificate before claiming. Without it, HMRC will reject the claim.
What happens to my EIS or SEIS shares when I die?
EIS and SEIS shares that have been held for at least two years and still qualify may attract Business Relief, which can reduce their value for inheritance tax purposes by up to 100 percent. This is separate from the income tax and CGT reliefs and is subject to its own qualifying conditions. It is worth discussing with an estate planning adviser because the rules can change and the shares must still meet the qualifying criteria at the date of death.

Related calculators

Sources

  1. HMRC — Income Tax Rates and Personal Allowances 2026/27, HM Revenue & Customs
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