This lean calculator tells you what your startup is worth, based on last year’s revenue and projected revenue for this year, how many paying customers you have and how much you charge them monthly for your product or service.

It’s very straightforward Facebook Math (which is variable, too).

The calculator was made by Verelo founder Andrew McGrath. It’s worth $1 billion.

Update: need a $1 billion startup idea first? Here you go (via Steve Guengerich).

(Via @Folke, who found it on Hacker News)