Open enrollment for the public health insurance marketplace lasts a month longer than usual this year — which means there’s still time to get coverage.

Through Jan. 15 — unless your state has a different closing date — you and your family can sign up for a plan through the federal marketplace (or your state’s, if it has one) if you need health insurance. The exchange also will alert you if you qualify for Medicaid instead or if your kids could qualify for the Children’s Health Insurance Program, otherwise known as CHIP.

“Marketplace coverage is the most affordable it’s ever been,” said Karen Pollitz, a senior fellow with the Kaiser Family Foundation. “Even if you looked in the past and were discouraged, it’s a good idea to check again.”

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Altogether, there are about 27 million uninsured Americans, recent Kaiser research shows. An estimated 10 million of them could qualify for financial help with private insurance through the public marketplace. Another 7 million could get coverage through Medicaid and/or CHIP.

Already, 13.6 million people have signed up for 2022 coverage through the federal exchange or a state marketplace, according to the Centers for Medicare & Medicaid Services.

Most enrollees — which includes the self-employed and workers with no job-based health insurance — receive subsidies (technically tax credits), which reduce what you pay in premiums. You also may qualify for help with cost-sharing like deductibles and copays on certain plans, depending on your income.

For 2021 and 2022, the subsidies are bigger, due to legislation passed in March. Before that expansion, the aid was generally only available to households with income from 100% to 400% of the poverty level.

That income ceiling is eliminated through next year, and the amount that anyone pays in premiums will be limited to 8.5% of their income as calculated by the exchange. (The Democrats’ $1.75 trillion Build Back Better Act, which cleared the House in November but has stalled in the Senate would extend the changes through 2025.)

Be aware that although people who collected unemployment at any point this year could qualify for zero-premium health plans through the marketplace, that provision is not in place for 2022 (although it, too, would be extended through 2025 under the House-passed Build Back Better Act).

The marketplace subsidies that you’re eligible for are based on factors that include income, age and the second-lowest-cost “silver” plan in your geographic area (which may or may not be the plan you enroll in).

For example, a 30-year-old with $35,000 in income would pay, on average, $142 a month for a silver plan — instead of $389 monthly — after a premium tax credit of $247, according to the Kaiser Family Foundation’s online estimating tool. A married couple, both age 50, with one child under age 18 and income of $65,000 would get $1,169 monthly, on average, to bring the cost of a silver plan down to $316 from $1,485.

The best place to start if you’re new to this is healthcare.gov, where you can create an account and explore your plan options. Or, if your state operates its own health-care exchange, the federal site will direct you to it. Once you enter information such as income and number of dependents, you should be told what help you can qualify for.

If you want to window-shop without creating an account, there is a tool on the federal exchange (or on your state’s site) that lets you enter general information about yourself to see if you qualify for subsidies and how much you’d pay in premiums.

Meanwhile, in states that expanded Medicaid, you can qualify for coverage through the program if your income is no more than 138% of the federal poverty level. For an individual, that would mean up to $17,774; for a family of four, $36,570. (The Build Back Better Act also would create subsidies for individuals in states that have not expanded Medicaid.)

It’s also worth noting that if you qualify for Medicaid, you can sign up at any time (not just during this open enrollment). The program bases your eligibility on your income at the time you enroll.

However, for a marketplace plan, you need to estimate your income for the full year. So if you underestimate your 2022 income for a marketplace plan and your subsidies are based on that amount, you may end up having to give back some at tax time in 2023.

Likewise, if you overestimate your income, you would generally be able to claim an additional tax credit when you file your 2022 taxes in 2023. You also could adjust your income estimate during the year if it changes, Pollitz said.

The bottom line is that anyone who is uninsured should at least check what their options are, she said.

“If you haven’t looked to see what you qualify for, you really should,” Pollitz said. “By our estimate, millions of people could be pleasantly surprised.”