SEIS Tax Relief Calculator
Calculate Seed Enterprise Investment Scheme reliefs: 50% income tax relief up to £200,000, 50% CGT reinvestment exemption and the loss-relief downside.
Data verified · July 2026
How much SEIS relief can I claim?
50% of the amount invested, on up to £200,000 per tax year — limited to your income tax liability, with a carry-back option to the previous year.
Source: GOV.UK — Seed Enterprise Investment Scheme (gov.uk/guidance/venture-capital-schemes-apply-to-use-the-seed-enterprise-investment-scheme); HS393. · updated 2026
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Everything about SEIS Tax Relief Calculator
📋Overview+
Computes SEIS reliefs (2025/26): 50% income tax relief on up to £200,000 invested per year, permanent exemption of 50% of a capital gain reinvested in SEIS shares (24% CGT saved), CGT-free growth after 3 years and loss relief — combined protection can approach three-quarters of the investment.
💡 Best practices
- Combining 50% income relief with the CGT exemption and loss relief can cover over 72% of the invested amount in the worst case.
- SEIS targets very early-stage companies — higher risk than EIS, hence the richer reliefs.
- The £200,000 annual investor limit doubled from £100,000 in April 2023.
🔢 Concrete example
£10,000 SEIS investment funded by a £20,000 gain: £5,000 income tax relief plus £1,200 CGT saved (50% exemption × 24%) — net cost £3,800, worst-case loss £2,750 after loss relief at 45%.
📖User guide+
How to use this calculator
- 1
Enter the SEIS investment amount (up to £200,000 per year).
- 2
Optionally cap the relief with your income tax liability.
- 3
Add a capital gain reinvested to apply the 50% CGT exemption.
- 4
Read the combined relief, net cost and worst-case downside.
📚Glossary+
- 50% income tax relief
- A tax reducer worth half the amount invested (max £100,000 relief on the £200,000 annual limit), clawed back if shares are sold within 3 years.
- CGT reinvestment exemption
- Half of a chargeable gain reinvested in SEIS is permanently exempt — unlike EIS deferral, it never revives.
ℹ️Sources & updates+
Last data update
July 5, 2026
Sources and references
GOV.UK — Seed Enterprise Investment Scheme (gov.uk/guidance/venture-capital-schemes-apply-to-use-the-seed-enterprise-investment-scheme); HS393.
The data in this calculator is updated regularly to reflect the latest official rates. When in doubt, consult the official sources listed above.
FAQ — SEIS Tax Relief Calculator
How much SEIS relief can I claim?+
50% of the amount invested, on up to £200,000 per tax year — limited to your income tax liability, with a carry-back option to the previous year.
How does the CGT reinvestment relief work?+
Reinvest a chargeable gain into SEIS shares and half of that gain (up to the amount invested) becomes permanently exempt from CGT — a 12% effective saving at the 24% rate.
What is the worst-case loss on SEIS?+
If the company fails, loss relief on the net investment at your marginal rate applies: for a 45% taxpayer, the maximum loss is about 27.5p per £1 invested (before counting any CGT exemption benefit).