Today is the final day to sign up for health insurance in the federal exchange, marking an end to a 15-day grace period the Obama administration allowed to help usher more applicants into the program.

According to the White House, more than 7.5 million people have signed up for the exchanges, with 400,000 applications coming in after the official deadline of March 31.

The administration added the extra days to help those who experienced delays because of technical problems in creating an account or signing up for a plan, although the website also offers the extended time for those who “couldn't start or continue,” the application process. People who want to enroll but didn't start an application can call a “marketplace call center” and tell the operator they tried but failed to start an application. People who sign up by April 15 will have coverage beginning May 1. Those who still do not have insurance must pay a $95 fee or 1 percent of their income, whichever is higher.

The deadline comes a day after the Congressional Budget Office reported 12 million people will receive health insurance this year under Obamacare. The CBO also projected the health care law would yield “lower net costs” to the federal government because of narrower networks and lower payments to healthcare providers and tighter controls over using the insurance policies. Premiums, the CBO predicts, will rise by about $100 in 2015, less than projected.

“Evidence continues to mount that the Affordable Care Act is building a healthier and stronger future for our nation, improving the quality of care and holding down cost growth for millions of American families,” House Minority Leader Nancy Pelosi, D-Calif., said Monday.

But problems also persist.

On the insurance blog, an April 1 post titled “Open Enrollment is Over — We can still help you get covered,” is filled with inquiries from frustrated people who had trouble signing up either because the website was busy or call centers were jammed.

Some customers said they were not able to finalize their enrollment, including a woman who is seven months pregnant and signed up in December, only to be told her application is still pending, which has kept her from seeing her doctor in April.

“I thought by signing up in December when we were supposed to, it would already be processed,” Terece Evans wrote on “I have gone to the State Office, I have made phone calls as has my insurance rep but receiving the same response: You're still pending. Please, please may I have some help in getting this resolved?!”

The website opened disastrously in October, with most people unable to log on, never mind search for plans or sign up for one.

Much of the blame was heaped on Health and Human Services Secretary Kathleen Sebelius, who resigned last week.