Nash - Equity and Cap Table Planner
Describe your startup and founding team, and get a cap table structure to take to your solicitor, with the dilution modelled and the UK-specific parts explained.
Named after John Nash, whose bargaining solution describes the split rational partners reach when walking away is worse for everyone.
A startup cap table records who owns what. Early on it has four moving parts: the founders, an option pool for the people you have not hired yet, whatever converts when you raise, and the investors who come in at a priced round. The numbers matter less than understanding what each round does to the rest: a 15% pool and a 20% seed round leave founders with about 68% of what they started with, before anyone has done anything wrong. Give the cap table calculator below your funding stage, what you are building and who is on the team, and it proposes a founder equity split, models the dilution round by round and lists what to take to your solicitor and accountant. It is a planning aid, and nothing it produces is legal, tax or financial advice.
When a free tool is not enough
You do not have to give away 10% to get a CTO.
The single largest line on most early cap tables is a technical cofounder, and it is permanent. We put experienced CTOs on retainer instead, which costs money rather than ownership and stops when you have your own team. If you are modelling a technical cofounder grant right now, it is worth knowing what the alternative costs.
How to use Nash, the Equity and Cap Table Planner
Set your funding stage
Bootstrapped, raising pre-seed, raising seed, or post-seed. It changes the pool size, the instruments and what is still negotiable. Add a raise target if you have one and the dilution is modelled on it. Leave it blank and Nash assumes a conventional round for your stage and says so.
Describe what you are building
The product, who it is for, and how far along you are. Two or three sentences is enough; traction changes the answer more than the sector does.
Be honest about the team
Each person, what they do, full-time or not, taking a salary or not, and what they brought in. Unequal contributions are the whole point of the exercise, so say where they are unequal.
Read the open questions first
These are the decisions your description did not settle, and they lead the Next steps tab. Answering them with your co-founders is worth more than the split table itself.
Take the adviser list to a solicitor
The output ends with specific questions for a startup solicitor and an accountant. That list is the most valuable part: it turns an hour of their time into a decision rather than an explanation.
How to split equity between founders
Almost every founder asks for a formula, and there is not one. An equity split is a negotiation between people who are about to spend years together, and the numbers are the easy part. What this tool does is show you what the numbers do, so you can have that conversation with the arithmetic in front of you instead of a feeling.
The instinct is an even split, and for two people going in equally, full-time, from the same standing start, it is usually right. It gets wrong when the contributions are not equal and nobody wants to say so. One person is full-time and the other is not. One has been at it eighteen months and the other joined last quarter. One is taking a salary and the other is not.
Those gaps do not need to be settled in the founder split. Differential vesting handles a time difference. A cash-versus-equity trade handles the salary difference. A smaller initial grant with milestones handles someone who is not yet all in. The worst outcome is an even split that one person privately thinks is unfair, because that conversation does not go away, it just gets more expensive.
- Vest everything, founders included. Four years with a one-year cliff is the convention, and the reason it exists is the co-founder who leaves in month eight holding a third of the company.
- Decide what happens if someone leaves before you need to know. Good leaver and bad leaver provisions are a ten-minute conversation now and a lawsuit later.
- Write down what each person committed to, not just what they own. Hours, runway, salary expectations.
- Do not leave a slice unallocated for "a future co-founder". Either you are hiring one, in which case it comes out of the pool, or you are not.
Option pools, and the bit that catches people out
An option pool is equity set aside for employees you have not hired yet. At seed, investors will expect somewhere around 10% to 15%, sized against the hires in your plan for the next 18 months rather than a round number. A fully diluted cap table counts the whole pool as though every option had already been granted and exercised. Investors usually price a round on that basis, and the planner shows your split the same way.
Here is the part that surprises founders. An investor will usually require the pool to sit in the pre-money, which means it comes out of the existing shareholders and not out of the new money. So a "20% round" with a fresh 10% pool dilutes you by closer to 30%. It is standard, it is negotiable at the margins, and it is much easier to argue about before you have signed a term sheet.
Size it from the actual hires. Two senior engineers at 0.5% to 1% each, a first commercial hire, a head of something. If you cannot name the roles, the pool is guesswork and probably too big.
What dilution actually does
Dilution is not a loss. Your percentage goes down and the thing it is a percentage of goes up, which is the entire point of raising. Founders who optimise for their percentage rather than the value of their holding end up owning most of something small.
What you do need is to see it coming. Two rounds and a pool, each individually reasonable, can take two founders from 50% each to the high twenties without anyone making a bad decision. That matters because control and motivation both live in those numbers, and because the third round is the one where it starts to hurt.
Seeing it coming is what a cap table simulator is for. The tool above models it stage by stage and shows the arithmetic rather than asserting the result. If you cannot see how 100% became 62%, you have not learnt anything you can use in a negotiation.
SEIS, EIS, EMI and ASA vs SAFE, explained for UK founders
Most cap table advice online is American, and the instruments are different here. Getting this wrong is expensive in a way that is hard to undo.
SEIS and EIS, the Seed Enterprise Investment Scheme and the Enterprise Investment Scheme, are the schemes that make UK angel investment work. They give your investors substantial income tax relief, which is often the reason a cheque gets written at all. They come with conditions on the company, the shares and the money, and the shares have to be ordinary with no preferential rights. Get advance assurance from HMRC before you raise, not after.
A US-style SAFE is not the standard UK instrument. Here it is usually an advance subscription agreement (ASA), which is a payment for shares issued later and is SEIS-compatible if drafted properly, or a convertible loan note, which is debt and generally is not. That distinction decides whether your angels get their relief.
EMI options are the tax-advantaged way to give employees equity in the UK, and they need an HMRC valuation and a scheme in place before you grant anything. Promising someone "1%" in an offer letter with no scheme behind it is a promise you cannot keep cleanly.
- Get SEIS/EIS advance assurance before you take money, not after.
- Use an advance subscription agreement rather than a convertible if your investors need SEIS relief, and have a solicitor draft it.
- Set up an EMI scheme and get the valuation before you promise anyone options.
- Keep one class of ordinary shares for as long as you can. Preference shares can break SEIS eligibility for everyone.
- File everything at Companies House properly and on time. A messy share register is found in diligence, always at the worst moment.
What this tool cannot do
It is not legal, tax or financial advice, and we are not regulated advisers. It reads a description you typed and proposes a structure to discuss. Issuing shares, SEIS and EIS eligibility, EMI valuations and anything to do with tax need a startup solicitor and an accountant, and they are cheaper than the mistakes.
It has not seen your articles, your existing share register, any agreement you have already signed, or the term sheet in your inbox. Anything already committed constrains the options in ways it cannot know, which is why the output lists open questions rather than pretending to certainty.
It will not value your company. Valuation is a negotiation with an investor, not a calculation, and any number a language model gives you for it is invented.
The planner is free, with three runs per person and no paid tier. Before the first result we ask for your name, work email and company, and for you to accept the terms. What you put in on your first run travels with your details to our CRM, inbox and team chat, so a person can read it and reply. After that, your input goes to the model to produce the plan. We keep each result, which can quote what you put in: it is emailed to you as a PDF and saved in our CRM. Either way, keep names and anything commercially sensitive out of it: you can describe a founding team as "two technical, one commercial, one part-time" and get the same answer.
Frequently asked questions
If both are full-time from the same starting point, an even split is usually right and arguing about 55/45 costs more than it saves. If the contributions are genuinely unequal, handle the difference with vesting schedules, a salary-versus-equity trade, or a smaller initial grant with milestones, rather than with a lopsided headline split that one person resents.
It depends on whether they are a founder or a hire. A technical co-founder who starts at the same time as the others, full-time and on the same terms, is a founder: an equal share is the usual starting point, and any real gap in contribution is handled with vesting or a smaller initial grant. A CTO who joins once the company exists, on a salary, is a senior hire. Their equity usually comes out of the option pool and is much smaller. In the UK that grant is often made as EMI options, which, among other conditions, are only open to employees who hold 30% or less of the company. Tell Nash which one you mean and the plan shows where their equity comes from and what it does to everyone else's.
At seed, investors typically expect 10% to 15%. Size it from the roles in your 18-month hiring plan rather than from a round number: two senior engineers at 0.5% to 1% each plus a couple of commercial hires gets you to a defensible figure. If you cannot name the roles, the pool is a guess.
Dilution is your percentage falling as new shares are issued. A priced seed round plus a fresh option pool commonly costs founders somewhere around 25% to 30% combined, because the pool usually sits in the pre-money and therefore comes out of the existing holders rather than the new money. That is standard. Seeing it before you sign is the part that matters.
Usually not. The US SAFE has no direct UK equivalent in common use. British pre-seed rounds are typically done on an advance subscription agreement, which is SEIS-compatible when drafted properly, or a convertible loan note, which is debt and generally is not SEIS-eligible. If your angels are investing for the relief, that distinction decides whether they get it.
They are UK schemes giving investors significant income tax relief on qualifying startup investments, and for many angels they are the reason the cheque exists. They impose conditions on the company, the shares and how the money is used, including that the shares be ordinary with no preferential rights. Get advance assurance from HMRC before you raise.
Enterprise Management Incentives (EMI) is a tax-advantaged share option scheme for smaller UK companies. Grant options at the market value of the shares and the employee usually pays no income tax or National Insurance when they exercise, and the growth in value is taxed as a capital gain when they sell. The company, the employee and each option have to qualify, the share valuation is usually agreed with HMRC before the first grant, and every grant has to be notified to HMRC. Set the scheme up before any offer letter promises options. When your plan includes an option pool, Nash's UK essentials tab covers EMI where it applies.
Yes, and four years with a one-year cliff is the convention. The reason is the co-founder who leaves in month eight still holding a third of the company, which is both unfair to whoever stays and a problem every future investor will make you fix. Agreeing it at the start costs nothing; retrofitting it costs goodwill.
No. It is a planning aid that reads a short description and proposes a structure to discuss. We are not regulated advisers. Share issuance, SEIS and EIS eligibility, EMI valuations and anything touching tax need a startup solicitor and an accountant.
Related from Metamindz
- Fractional CTOSenior technical leadership on a retainer, so the largest grant on your cap table does not have to be permanent.
- Technical due diligenceThe technical side of what an investor will look at before a priced round, run before they do.
- Cofounder job description generatorIf the answer to the equity question is that you need another founder, start with the role rather than the percentage.
- All free tools
Also known as: Cap Table Calculator, Founder Equity Split Calculator, Cap Table Simulator, Startup Equity Calculator.
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