Manhattan is the second-best place in the U.S. to be a single adult, trailing  San Francisco, according to a survey from Rent.com.

As of 2012 there were an estimated 494,899 singles in Manhattan, the survey found, 38% of the island’s population of roughly 1,572,295.

San Francisco ranked No. 1 on the list because 39% of its population was single.

The website defines singles as those over 20 who have never been married or are divorced, separated or widowed.

Manhattan got the highest possible score on a 1-1,000 scale in the survey’s “nightlife options,” “restaurant options” and “frequent coffee shop goers” indices.

In Rent.com’s lifestyle index, which represents how likely people are to be out on the town, Manhattan got a 781 out of 1,000.

The survey also found that singles in Manhattan don’t have to worry about being victims of crime, giving the city a score of 822 in its safety index.

Kathy Szwader, 27, a company vice president who lives in Middle Village, told amNewYork that late-night options cater to a single crowd.

“I’ve been to different states and their bars and clubs close significantly earlier,” she said. “In New York, there are places open until 4 [a.m.\] and coffee shops open 24 hours.”

Brandon Timmons, 23, a musical theater actor who lives in Harlem, is gay and newly single. He said the city is great for people of all sexual orientations.

“You meet people you’d never meet [because] everybody’s out,” he said. “We’re all walking; we're all on the train.”

Despite that, it’s often hard to find people who are looking to settle down, said Michelle Pardo, 29, a fingerprint technician who lives in Flushing.

“I’ve had a hard time finding a boyfriend. I go out on weekends and put myself in social situations,” she explained. But “even if a man is single, it’s hard to find someone who wants more than a one- or two-night stand.”

(With Sheila Anne Feeney)