The iconic New York Public Library in Midtown is getting a $300 million makeover — with plans for new entrances, plazas, bathrooms, elevators, a café and more public space for research and exhibitions.

The renovation — that will increase the library’s public space by about 20 percent — helps fulfill a duty to preserve the building’s “architectural wonder and its role as an important civic space, while also preparing it for the future,” said library president Tony Marx.