How do you translate people to square feet?

Companies think of space in terms of people, but real estate leases think of space in terms of square feet. In a typical office property, each person translates to roughly 250 square feet. If you have 30 employees, you will need roughly 7,500 square feet of office space. I have seen start ups using an extremeley dense open environment get as low at 140 square feet per person, which would mean 30 people could fit like sardines into 4,200 square feet. The number can be adjusted up or down depending on how open the enviornment is, but as a general rule of thumb 250 square feet per person is good place to start.