The estimates by DVRPC staff, compiled with county planners, will not be the agency's official projections until they are approved by the DVRPC board Jan. 26.
The latest projections suggest the Philadelphia region will continue to grow more slowly than the nation, whose population is projected to grow 31 percent over the same period.
The Philadelphia region's population in 2040 is likely to be older and more diverse than it is today, planners say. The increasing number of elderly residents will require better transit and more health-care services.
The region's suburbs will continue to grow, but the long, post-World War II population drain from Philadelphia and inner-ring suburbs is likely to reverse, said Mike Boyer, manager of long-range planning for DVRPC.
Philadelphia is predicted to grow by 105,000 people to 1.63 million, a 7 percent increase.
"We're taking a bullish position" on the city's future, said Gary J. Jastrzab, executive director of the Philadelphia City Planning Commission.
He said the city's population of Asian and Hispanic residents is likely to increase, and he predicted population growth would be especially robust in North Philadelphia neighborhoods near Temple University and along the central Delaware River waterfront. He said Fishtown, Northern Liberties, East Kensington, and parts of South Philadelphia are likely to grow faster than the city as a whole.
Boyer said Philadelphia is likely to continue to see an influx of young adults. To offset the city's long-term pattern of losing young families to the suburbs, the city will need to focus on improving education and safety, he said.
