The numbers just don’t add up.

The “abnormally high traffic” that crippled New York’s ObamaCare Web site for two days may have resulted from a malicious attack by hackers, computer-security experts said Wednesday.

The NY State of Health site recorded an astounding 10 million visits after opening for business Tuesday — although there are only about 1.1 million state residents without health insurance and just 330,000 are expected to buy ObamaCare for next year.

By comparison, the federal government’s heavily promoted HealthCare.gov site — a portal to the sites for all 50 states, the District of Columbia and America’s territories and commonwealths — drew just 4.7 million visitors the first day.

Late Tuesday, NY State of Health Executive Director Donna Frescatore said technicians were “looking into the cause of this abnormally high traffic.”

Darien Kindlund, manager of threat intelligence for the FireEye network-security company, said “the sheer volume” of visits to New York’s site pointed to a possible “distributed denial of service,” or DDoS attack, in which virus-infected computers bombard a site with traffic.

“The numbers are fairly compelling,” Kindlund said.

Hemant Jain, vice president of engineering for Fortinet, a network-security firm, said that “because [ObamaCare] is such a political issue, it could very well be a DDoS attack.”

“Certainly, you don’t expect everyone to wake up and access a Web site like that, so I have a feeling it may be an attack,” he said.

Matthew Prince, co-founder and CEO of CloudFlare, another security firm, said that while there wasn’t yet enough evidence to prove an attack, “it does not take a lot of technical resources” and hackers can be hired to disrupt a site for just a couple thousand dollars a day.

“There have to be people who disagree with [ObamaCare] enough to do that,” he added.

Throughout the day, the Web site displayed a banner message telling users to return later.

Freelance writer Cristina Gibson, 29, of Union Square, wanted to see how ObamaCare premiums compare to the $345 a month she currently pays for health insurance, but gave up in frustration after spending 40 minutes trying to navigate the site during a lunch break from jury duty.

“I’m interested in this, but not interested enough to be behind on stuff in my life,” she said.

Lawyer Greg Crawford, 50, of suburban Katonah, said he has Crohn’s disease and is hoping that ObamaCare will slash the “burdensome” cost of his current coverage.

But after creating an account Tuesday, Crawford got booted off the site and was unable to log in during a half-dozen attempts Wednesday.

“I’m not a big fan of the government taking over all this stuff politically, but I’m going to benefit from it tremendously as an individual, and I just wish it would work,” he said.

Additional reporting by Tara Palmeri and Lorena Mongelli