On average, listings lease in the $40's per square foot per year. The McLean submarket is going through a decline in rates. In the last 3 months, the median rate decreased $4 per sqft per year. That's a 9% decline in rent.
Compared to the rest of the Washington D.C. market, the McLean region has more expensive rates, and you'll have to negotiate above asking rent to be in this hot submarket.
In the last 90 days, 10 listings have been posted online, which means office spaces are probably leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 960 sqft. Most buildings in this region are close to 5 floors. Most buildings in this market were built in 1980 and are Class A.