To avoid the penalty, people must enroll in a plan by Feb. 15 or qualify for an exemption from the penalty.
If you're in the market for health insurance, here are some key questions and dates to keep in mind:
Can I enroll after Jan. 1?
Open enrollment for 2014 runs through March 31. If you buy coverage, say, on Feb. 10, it won't kick in until March 1. If you wait until March 31, your policy will take effect May 1.
There is no deadline for signing up for Medicaid or the Children's Health Insurance Program.
If I enrolled in a private health-exchange plan by Dec. 23, when is my premium due?
Recently, the federal government directed insurers to accept payment by Dec. 31 and encouraged health plans to push the deadline further.
Consumers who signed up by Dec. 23 and pay the first month's premium by Jan. 10 will have coverage on Jan. 1, the industry group America's Health Insurance Plans announced this month.
However, the federal government cautions that not all health insurers are extending the payment deadline, and some may require payment on or before Dec. 31, 2013.