By Karen Pallarito
HealthDay Reporter

FRIDAY, Dec. 20, 2013 (HealthDay News) — Attention last-minute shoppers: If you intend to buy a health plan through one of the new health insurance exchanges, and you want coverage starting Jan. 1, you must act quickly.

In most states, Monday, Dec. 23 is the deadline for selecting a plan that takes effect on the first day of the new year.

“We would really encourage people to start now. Don’t wait until the deadline to enroll,” said Cheryl Fish-Parcham, deputy director of health policy at Families USA in Washington, D.C.

People need to leave themselves enough time to gather the information they need to complete an insurance application, select a health plan and pay the premium by the health plan’s deadline, she said.

The pre-Christmas race to buy health insurance is another consequence of the troubled launch of the Affordable Care Act’s HealthCare.gov website and website difficulties in a number of state-run health insurance exchanges. Since the October launch of the health exchanges, sign-up and premium-payment deadlines have been extended to give people more time to enroll for coverage, but the new cut-offs come amid the holiday rush.

Many people aren’t aware of the various deadlines under the law, sometimes called Obamacare. What’s more, the deadlines may vary by state and by health insurer, health insurance agents and brokers said.

“There is a lot of confusion,” said Anna Causey, vice president of Combined Insurance Services Inc., a Pensacola, Fla.-based benefits broker.

Some people mistakenly believe they have until Dec. 31 to enroll in a plan that takes effect on Jan. 1, Causey said. Others don’t realize they could pay a federal tax penalty if they don’t have health insurance in place by March 31, she said.

Under the Affordable Care Act, most adults will pay a $95 penalty — or 1 percent of income — in 2014 if they don’t have health insurance coverage. The penalty rises to $695 — or 2 percent of income — by 2016.

To avoid the penalty, people must enroll in a plan by Feb. 15 or qualify for an exemption from the penalty, Causey said.

If you’re in the market for health insurance, here are some key dates to keep in mind:

What’s the latest I can enroll in coverage for Jan. 1?

Consumers shopping on HealthCare.gov, the federal portal serving individuals in 36 states, have until 11:59 p.m. ET on Monday, Dec. 23, to enroll if they want coverage to take effect on the first day of the new year.

What if I enroll through my state health insurance exchange?

Deadlines for Jan. 1 coverage may differ in states that operate their own health exchanges.

Health insurers in Maryland have agreed to extend the sign-up deadline through Dec. 27, state officials announced Tuesday. Consumers must pay their premiums by Jan. 15, the officials said.

Make sure to check with your state health exchange.

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 enroll 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 sign 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 Wednesday.

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.

“Once you’ve enrolled, check with your plan that they’ve received your enrollment and what is the premium payment deadline and how do you go about paying your first month’s premium,” Fish-Parcham advised.

Is it better to enroll now or sometime before March 31?

Insurance brokers say it depends on your situation.

“The (health plan) options will not change,” said Karen Sweeney, benefit consultant with PIT4 Medical Insurance Consultants, in Mesa, Ariz.

She recommends that individuals who are uninsured or who are losing coverage on Jan. 1 “get with an educated insurance broker and make a selection by Dec. 23.”

People who have coverage that carries over into 2014, however, don’t necessarily need to rush to meet the Dec. 23 cutoff, brokers said.

More information

Need help with your insurance application? HealthCare.gov has tips for getting health insurance coverage.

To read a related HealthDay story on last-minute exemptions for people who’ve lost their health insurance under the Affordable Care Act, click here.