EIS SEIS Tax Relief Calculator United Kingdom

What the EIS and SEIS tax relief calculator does

The calculator adds up the reliefs available on a qualifying UK venture investment and shows what the shares cost you after tax. Enter the amount subscribed, the scheme, your Income Tax band and any capital gain you are reinvesting. It returns the Income Tax relief, the value of the capital gains relief, the net cost and the worst case if the company fails.

Under these schemes the tax treatment does much of the work. Investors often underestimate the combined effect of Income Tax relief, capital gains treatment and loss relief, and seeing all three together changes how the risk looks.

Income tax relief

The largest relief is against Income Tax, at the scheme rate on the amount you subscribe, up to the scheme’s annual limit. SEIS gives 50% on up to £200,000 a year. EIS gives 30% on up to £1 million, or £2 million where the amount above £1 million goes into knowledge-intensive companies that meet the research and development conditions.

The relief can only reduce your Income Tax for the year to nil, so it is worth nothing beyond the tax you owe, and any subscription above the annual limit gets no relief. The calculator caps the qualifying amount at the limit and shows the eligible figure separately, so an oversized subscription shows up as relief you are not receiving.

Relief can also be carried back to the previous tax year, which can make the difference between using it all and wasting part. This tool models one year; if you plan to carry back, apply the same rate to the amount you allocate to the earlier year.

Capital gains relief

The two schemes treat gains differently, and this matters more than the headline rates.

EIS offers deferral. A chargeable gain reinvested in the shares is postponed, up to the amount subscribed, and comes back into charge when the shares are sold or the qualifying conditions end. The cash-flow benefit is real, and the gain may eventually be taxed at a different rate, but it has not gone away.

SEIS offers reinvestment relief, which exempts half of a gain reinvested in the same tax year, again capped at the amount subscribed. That half is written off for good. The calculator values whichever applies at the current capital gains rate and shows the gain sheltered and the tax saved, so you can see which part of the benefit is permanent and which is deferred.

Share loss relief and the real downside

Early stage companies fail often, and the schemes allow for that. If the shares become worthless, the loss is measured after the Income Tax relief you already received, and that net loss can be set against income at your marginal rate.

Take a higher rate taxpayer who invests £20,000 under EIS. Income Tax relief at 30% is £6,000, so the net cost is £14,000. If the company fails, loss relief at 40% on £14,000 is worth £5,600, so the most they can lose is £8,400, well under half the cheque. Under SEIS, with 50% relief, an additional rate taxpayer’s worst case is smaller still.

One caveat sits outside this figure. A gain deferred under EIS comes back into charge when the shares are disposed of, including on a failure, so an investor who used deferral relief should expect that tax to reappear even if the company fails.

The holding period and clawback

The reliefs are conditional. You must hold the shares for at least three years, and the company must keep its qualifying status throughout. Sell early, or see the company stop qualifying, and the Income Tax relief is withdrawn and any deferred gain comes back into charge.

There are conditions on the investor too: broadly, you must not be connected with the business through employment or a substantial shareholding, and the shares must be new ordinary shares subscribed for in cash and fully paid. Advance assurance from HMRC gives comfort that a company qualifies, and the compliance certificate issued after the company starts trading is what you need before you claim.

Reading the results

Start with the net cost after all reliefs. Compare it with the capital genuinely at risk and use it to decide how much to invest. The relief as a share of the investment shows how much of the subscription the tax system has funded, which is the simplest way to compare an EIS opportunity with an SEIS one.

Then look at the worst case. Investors tend to size these positions against the gross amount, when what matters is what a total loss would actually cost them. With Income Tax relief, capital gains treatment and loss relief together, the gap between the two is usually large.

None of this tells you whether the company is any good. The reliefs improve the shape of the outcome, but they cannot rescue a bad investment, and shares in unquoted early stage companies are illiquid, high risk and frequently end up worthless.

All figures are an estimate based on the amounts you enter and the current HMRC rates and limits held as parameters. Your own claim depends on your tax position, the company’s qualifying status and the compliance certificate it issues. This is not investment or tax advice.

About This Tool: EIS SEIS Tax Relief

EIS SEIS tax relief: use this tool to get an instant, accurate estimate. The figures follow official GOV.UK guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.