For many it's unclear what their side projects are worth. Many want to sell, or have people interested in buying but have no idea how to get to a proper price. This calculator helps you figure out a base price to aim towards when negotiating selling your side project.
This is just a start and far from perfect: I'll keep adding more possible variable inputs and variations. If you have ideas on what to add, please tweet them to me and I'll implement them.
If you'd like to learn more about exiting your startup, I've written about it in the Exit chapter in my book about building startups. Other projects I made that you might like are a job board for remote jobs and a site to find the best places to live.