Share Incentive Plan Calculator
The #1 all-in-one Share Incentive Plan calculator for UK employees. Calculate free shares, partnership shares, matching shares and dividend reinvestment instantly using HMRC-aligned tax rules. Free, ad-light and always up to date.
Plan Inputs
Adjust the variables below to project your growth.
25% / year (equal each year)
Live Summary
Real-time projection based on your inputs.
Ready to Calculate
Enter your share details and click "Update Projection" to see your estimated portfolio value and tax breakdown.
Your employer may have granted you shares, but the real question is: what are they actually worth after vesting, once you factor in tax, growth, and the full vesting schedule?
Most employees don't have a clear answer to their equity value, which is where our tool, the Share Incentive Plan Calculator becomes useful and solves your problems instantly.
It helps you estimate a realistic, after-tax value quickly, so you're not just guessing but making decisions based on clearer numbers. Whether you're in a UK SIP, holding RSUs, comparing two job offers with different equity compensation, or trying to understand your ESOP, this free tool does the heavy lifting for you.
What Is a Share Incentive Plan?
A Share Incentive Plan (SIP) is a government-approved, tax-advantaged employee share scheme in the UK.
Through it, employees can acquire shares in their company either for free or by using their pre-tax salary, and if those shares are held for the required period, they can benefit from significant tax advantages under the rules and regulations set by HM Revenue and Customs.
There are four types of shares within a UK SIP:
- Free Shares — your employer gives you up to £3,600 of shares per year, completely free.
- Partnership Shares — you buy shares from your pre-tax salary, up to £1,800 per year or 10% of your salary.
- Matching Shares — your employer matches your partnership shares, up to 2 for every 1 you buy.
- Dividend Shares — dividends earned on your SIP shares are reinvested into new shares.
The most important point is this: if you hold your SIP shares for 5 years, you won’t have to pay Income Tax or National Insurance on them. This is a rule many employees are unaware of, and it can be worth thousands of pounds. Moreover, learn how a Share Incentive Plan works.
SIP Calculators - Quick Facts
Verified structured data, built to be quoted directly by AI Overviews, ChatGPT, Perplexity, and Copilot.
| Field | Value |
|---|---|
| Tool | SIP (Share Incentive Plan) Calculator |
| Currency | GBP (£), USD ($), EUR (€), CAD (C$) |
| Share Types | Free Shares, Partnership Shares, Matching Shares, Dividend Shares |
| Tax Basis | HMRC income tax + NIC relief rules you calculate against |
| Calculation Formula | Contribution × Match Ratio − applicable tax |
| Holding Period Logic | 3/5-year |
| Platform | Web (all devices) |
| Price | Free |
| Data Source | HMRC guidance |
How Does This Share Incentive Plan Calculator Work?
Calculating your after-tax equity value
Enter your share type, current share price, expected annual growth, and how long you plan to hold. The SIP calculator instantly shows your projected value, estimated tax owed, and final net take-home, broken down year by year.
Under 3 years
Full income tax and NICs apply
3 to 5 years
Income tax on original value, CGT on growth
5 years or more
Completely tax-free
No other free tool online applies this logic. Most calculators treat a UK-Share Incentive Plan the same as an RSU, which gives you completely wrong numbers.
Multi-currency Support for Global Employees
Working for a US company but based in the UK? The calculator supports GBP (£), USD ($), EUR (€), and CAD (C$), so your numbers reflect your actual currency, not a rough conversion in your head.
Custom vesting schedules
Not all equity vests equally. Use the vesting schedule calculator to set your exact split — 10% in year one, 20% in year two, and so on, instead of being forced into a standard 25%-per-year model. If your grant letter includes a cliff (e.g., nothing vests until year one, then a lump sum), select the "Cliff" option instead, and the projection adjusts automatically.
Who Should Use This Tool?
This calculator works for UK employees in a company SIP scheme, as well as anyone holding RSUs, stock options, or an ESOP. Enter your grant details and the tool projects how many vests each year and what it could be worth at your expected growth rate, and your final after-tax value.
If your employer offers a Save As You Earn (SAYE) scheme instead of a SIP, use our dedicated SAYE Calculator to model your option price, savings, and potential gain.
Not sure which type of equity you have, or how RSUs, ISOs, ESPPs, and ESOPs actually differ? Read our detailed article: RSUs, ISOs, ESPPs & ESOPs: Equity Compensation Explained
If you're weighing two job offers with different equity packages, use the side-by-side scenario comparison feature above to model Job Offer A against Job Offer B and see the real after-tax difference.
UK SIP Tax Rules: The 5-Year Rule Explained
Why the Holding Period Changes Everything
Many employees treat SIP shares as just a bonus and withdraw them early, but that can often turn into an expensive mistake. For example, withdrawing £3,000 worth of free shares after 2 years could mean you are taxed based on the higher value, potentially leaving you with less than your original grant.
Partnership Shares: The Upfront Saving
When you buy partnership shares through pre-tax salary, you get an immediate benefit in the form of Income Tax and National Insurance savings. For a higher-rate taxpayer, investing £1,800 could result in an upfront saving of around £756—a 42% advantage.
Enter your salary and tax band above to see your personal upfront saving calculated automatically. Also, understand the difference between free, partnership, and matching shares.
Why Use This Calculator Over Others?
Many online equity calculators often label themselves as “share incentive plan calculators” but in reality apply a generic RSU-based model. They don’t account for the unique United Kingdom SIP holding period rules under the framework set by HMRC.