SEIS & EIS Investment Tax Relief Calculator
Calculate the tax benefits of investing through the Seed Enterprise Investment Scheme (SEIS) and Enterprise Investment Scheme (EIS) for 2026/27. See your income tax relief, CGT exemptions, loss relief, and effective investment cost.
Annual limit: £200,000
Used to determine your marginal tax rate — currently 40.0%
SEIS: 50% of reinvested gain exempt from CGT.
Total Investment
£50,000
Income Tax Relief
£25,000
Effective Cost
£25,000
after income tax relief
If the investment becomes worthless, here is how tax relief reduces your loss:
| Total investment | £50,000 |
| Less: income tax relief received | −£25,000 |
| Allowable loss | £25,000 |
| Loss relief at 40.0% marginal rate | −£10,000 |
| Net loss after all reliefs | £15,000 |
Loss relief can be claimed against income tax or capital gains tax in the year of loss or carried back.
Assumes shares held for 3+ years (qualifying for CGT exemption). All figures include tax reliefs.
| Scenario | Share Value | Total Return | Profit / Loss | Return |
|---|---|---|---|---|
| Best case: shares double | £100,000 | £125,000 | +£75,000 | +150.0% |
| Base case: shares flat | £50,000 | £75,000 | +£25,000 | +50.0% |
| Worst case: total loss | £0 | £35,000 | -£15,000 | -30.0% |
Best case: shares double
Base case: shares flat
Worst case: total loss
Frequently asked questions
What is SEIS tax relief?
The Seed Enterprise Investment Scheme (SEIS) offers 50% income tax relief on investments up to £200,000 per tax year in qualifying early-stage UK companies. If you invest £100,000 in a SEIS-qualifying company, you can reduce your income tax bill by £50,000, making the effective cost of your investment just £50,000. Gains on SEIS shares are also exempt from CGT if held for at least 3 years.
What is EIS tax relief?
The Enterprise Investment Scheme (EIS) offers 30% income tax relief on investments up to £1,000,000 per tax year (£2,000,000 for knowledge-intensive companies). EIS also provides CGT exemption on gains if shares are held for 3+ years, CGT deferral on other gains reinvested into EIS, and loss relief if the investment fails.
What is the difference between SEIS and EIS?
SEIS targets earlier-stage companies and offers higher income tax relief (50% vs 30%) but with a lower annual investment limit (£200,000 vs £1,000,000). SEIS also offers CGT reinvestment relief (50% of gains reinvested are exempt), while EIS offers CGT deferral on existing gains. Both require a minimum 3-year holding period and offer loss relief if shares become worthless.
Can I claim both SEIS and EIS relief in the same tax year?
Yes, you can invest in both SEIS and EIS qualifying companies in the same tax year, up to the respective annual limits (£200,000 for SEIS, £1,000,000 for EIS). The relief for each scheme is calculated separately. You can also carry back relief to the previous tax year, effectively doubling your relief window.
What happens if my SEIS or EIS investment fails?
If your investment becomes worthless, you can claim loss relief. The allowable loss is the amount invested minus any income tax relief already received. This loss can be offset against your income tax or capital gains tax at your marginal rate. For example, if you invested £100,000 via SEIS (receiving £50,000 income tax relief) and the company fails, your allowable loss is £50,000 — and at a 40% marginal rate, you would reclaim a further £20,000, limiting your total loss to just £30,000.