It depends on the kind of duties you are expected to perform and the risk you are taking by joining the company at this stage. If your focus is JUST (and only)

It depends on the kind of duties you are expected to perform and the risk you are taking by joining the company at this stage. If your focus is JUST (and only) the tech its not a founder position - its senior executive. Founders are expected to do much more for the company than a senior executive. Founders help in crafting the overall strategy and are expected to do whatever is required by the company (over and above your primary responsibility, which is in tech in your case). The risk is mostly defined by how stable the company is - is it funded already? how many employees did the company have at the time of joining? what kind of traction has already been gained over the past year? how uncertain is the future of the company in terms of its direction? The length of existence of the company is not much of a factor if there hasn't been any traction in that time period. In the end it all boils down to what you and the CEO count as fair. A starting point would be to look at the equity portion in the startup school video here - http://startupclass.samaltman.com/courses/lec18/ http://startupclass.samaltman.com/courses/lec18/ Hope it helps in some small way.