You need to act today if you want to claim a missing stimulus payment this year from the IRS. To get your money, you need to register your claim for a first-time or catch-up stimulus check with the IRS by 12 p.m. PT (3 p.m. ET) today, Saturday, Nov. 21.

Below, we explain how to learn if you are eligible for more economic impact money, how to estimate your total stimulus payment, what to do to claim any money owed, and what happens if you can’t make the deadline. This payment is separate from a second stimulus check that Congress may or may not approve in the next few months as part of another economic stimulus package if negotiations can finally yield a bipartisan agreement on the substance of the legislation.

The federal government still owes millions of Americans from the first round of coronavirus relief payments; according to ProPublica, more than 12 million people still hadn’t gotten all that they were due by late October. With today’s deadline, we outline who may qualify for more money in the first round and who might not be eligible for a second payment, should there be one — read on for more information. This story was updated recently.

People who don’t normally file a tax return

In September, the IRS started contacting 9 million Americans who may qualify for a payment but perhaps didn’t know they needed to register to claim it. This group — which the IRS categorizes as “nonfilers” — includes people who didn’t file a tax return in 2018 or 2019, such as older adults, retirees, SSDI recipients and individuals with incomes less than $12,200. You’ll need to file a claim using the Non-Filers tool.

People missing a payment for a dependent child

Under the CARES Act, each qualifying child dependent — those 16 years and younger — was eligible for a $500 check. But some people’s payments were short $500 for each eligible dependent.

As with nonfilers, if you’re missing a dependent you can claim it today, Nov. 21, here and receive the payment in December. You can use our stimulus check calculator to get an idea of how much you may be owed. If you miss the deadline, you can claim the payment on your 2020 federal tax return in 2021.

Note that in a few cases, where parents are separated or divorced and share joint custody of a dependent, each parent can get a $500 payment per eligible child, so you may not even be aware you’re eligible for the payment to begin with.

People whose checks were garnished by mistake

Although there are a few cases where the federal government or a debt collector could seize your payment to cover an outstanding debt, in general, if you qualify for a check, it’s yours to spend or save as you want. One area where the federal government can garnish a check is for overdue child support. However, if the parents are separated or divorced, only the spouse who owes child support should have the check seized.

According to the IRS, the parent who does not owe child support should receive their portion of the payment without having to take action. If you haven’t received your check, the IRS said it is working to send out the missing payments. While you don’t have much recourse to appeal IRS decisions, you can also try the Non-Filers tool to create a record of your claim.

People who used our stimulus check calculator and suspect their check amount is wrong

Finally, if after using our stimulus check calculator, you find you may have qualified for a bigger payment than you received, you can check the IRS Get My Payment tool to see if a check is in the works. If the IRS is waiting on information from you before it sends your check, you may still have time to request one this one year.

US citizens who live abroad, some noncitizens in the US, plus some in US territories

The IRS has rules that set the payment eligibility guidelines for US citizens who live abroad and non-US citizens who work in the US — along with spouses of nonresident aliens. We have a guide that walks through the various eligibility scenarios along with what to do if you qualify but didn’t get a check.

People who are incarcerated qualify by court order

Since April, when it first started sending payments, the IRS has gone back and forth on whether those who are in US jails and prisons qualify for a stimulus check. A recent ruling from a federal judge in California, however, seems to have settled the question — at least for now — and is requiring the IRS to contact those incarcerated who can file a claim for a stimulus check. The deadline to file a claim through the mail has passed (it was Nov. 4) but those who are incarcerated have till today, Nov. 21, to file online, if they can access the internet, using the IRS Non-Filers tool.

The IRS has appealed the case.

What if the Nov. 21 deadline goes by?

You’ll still have a chance to claim your stimulus check money from April, even if you miss the Nov. 21 deadline to file a claim with the IRS. You’ll just have to wait until tax season 2021. While the IRS doesn’t have specific instructions yet, the agency has said it will publish details as the date gets closer.

For everything to know about the first payment, see our guide to the first round of checks. We also have an idea of how quickly the IRS could send out the second round of payments if another stimulus payment is approved and what other benefits you might expect in another economic relief package.