What’s the best way to raise the right amount of money?

Paul Graham (Co-Founder & Partner at Y Combinator)
How to Raise Money

If you’re so fortunate as to have to think about the upper limit on what you should raise, a good rule of thumb is to multiply the number of people you want to hire times $15k times 18 months. In most startups, nearly all the costs are a function of the number of people, and $15k per month is the conventional total cost (including benefits and even office space) per person. $15k per month is high, so don’t actually spend that much.