You may not be able to claim your missing payment during tax season without these details.Sarah Tew/CNET

You need a letter to claim missing stimulus money on taxes. Why and what to do if you lost it

If you got a stimulus payment, you should've received an IRS notice in the mail confirming it. Here's what to do if you can't find it.

by · CNET

The IRS has officially closed stimulus check season. As of Feb. 16, the agency said it had finished sending out all of the first and second stimulus checks it was required to by law. (Jan. 15 was the cutoff mandated in the December bill.) Going forward, anyone missing the money they qualified for will need to claim it as a Recovery Rebate Credit when they file a 2020 tax return, the IRS said. You'll need a notice you received in the mail from the IRS to do that.

That notice includes information on your stimulus check money for up to $1,200 the first round and $600 the second -- use our calculator to find out how much you should have received in a first or second check. But what happens if you never received that letter, or if you lost it or threw it away? We've got everything you need to know about how to get a copy of the IRS information needed to claim any missing stimulus money on your taxes

Also, here's more information on how to file for the stimulus rebate credit, why you might want to file your taxes early and set up direct deposit when you do, and everything a new stimulus bill could contain when it's approved, including a third stimulus check for more than double the second payment. Yes, timing yet another stimulus check to coincide with tax season makes things complicated, but we're here to help sort it all out. This story was updated recently.

IRS Notices 1444 and 1444-B -- what they're for and why you need them to claim your missing money

Within 15 days after the IRS issued your first and second payments -- if you qualified for stimulus money -- the agency would have mailed a notice to your last known address with your information on the payment. For the first payment, the IRS would have sent you Notice 1444 and for the second, Notice 1444-B. 

The IRS said you'll use the information from these notices to claim money you were eligible to receive, but didn't, when you file your taxes this year. Here's more information on using the Recovery Rebate Credit Worksheet to figure out the credit you can claim on your taxes. You'll essentially enter the total amount you determine you're owed on line 30 of the 2020 1040 or 1040-SR tax forms.

Where else can I find the information that was in my IRS notice if I can't find the letter?

If you don't have the IRS confirmation notice, you can find the information in your federal tax account, using the IRS website. 

If you don't have an account set up with the IRS, head to the IRS account page and tap the blue button that says Create or view your account to get started.

You'll need to have some information on hand to set up your account, including tax and financial information, plus an email address and a mobile phone number to receive activation codes.

The IRS said for married couples who are filing jointly, each spouse will need to log into their own account.

The IRS has sent out two rounds of stimulus payments.Sarah Tew/CNET

What do I do if I can't complete the IRS registration?

The online registration process can take about 15 minutes. During the setup process, the IRS will first email and then text two activation codes. If the codes don't come through, the agency will mail you a letter with an activation code, which can take five to 10 days to get to you. If you want to track the letter, you can use this free service from the USPS.

Once you've set up your online account with the IRS, you can check your account for the information contained in the notice. If your stimulus payment information is not available when you check, the IRS said it should be in the coming weeks.

For more information on tax season and your stimulus check, here's what you need to know about tax deadlines, why you want to file early and how to estimate the size of your second check. (You can also estimate the size of your next stimulus check.)