What would it rent for? Zillow will guess

Property portal calculating 'Rent Zestimates' for 90 million properties

Branching out from home valuation "Zestimates," Zillow.com is now generating estimated monthly rents for about 90 million homes or apartments — whether they’re actually available for rent or not.

Like the automated home valuations that helped Zillow become one of the most popular real estate sites on the Internet, "Rent Zestimates" depend in part on the physical attributes of homes gleaned from public records, such as the number of bedrooms and square footage.

To generate its home valuation Zestimates, Zillow plugs data on nearby closed sales into a formula that generates automated property valuations. Rent Zestimates, meanwhile, use both current and historical rental listings data, the company said.

Because nearly three-quarters of renters do not negotiate their rent, rental listings are a "close proxy" for final rent price, the company says.