There are a few reasons why you should keep that letter from the IRS confirming your stimulus check.
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Did you get a letter signed by President Joe Biden about your third stimulus check? You’ll want to hold on to this letter from the IRS, because you’ll need it if you think you received the wrong amount (calculate your total here) or if you haven’t got a payment at all.

If you did lose the letter — or haven’t received it — we’ll tell you where to locate a copy so you can claim any missing money through an IRS payment trace. Also, if the IRS didn’t account for you having a new baby or gaining a dependent when calculating your payment total, you might qualify for more. Plus, if the IRS based the amount of your third stimulus payment on your 2019 taxes, but you made less money in 2020, you could be eligible for more money. Keep in mind that if you moved or changed your primary address recently, it’s a good idea to notify both the IRS and the US Postal Service.

The final day to file your taxes this year has passed, but if you requested a tax extension, you’ll still be able to claim a recovery rebate credit when you file your income tax return if you’re missing a stimulus payment. (You can use our first stimulus check calculator and second check calculator to see your estimated total.) Also, here’s how to track your stimulus payment if it hasn’t yet arrived and how to see if an employer owes you back wages.

Why do I need to hold on to the IRS letter I received about my stimulus check?

The IRS letter that arrives about 15 days after your third stimulus check, which confirms your payment, is officially called Notice 1444-C. Signed by the president, the letter shows the amount you were paid and how you were paid (mail or direct deposit). The letter also advises you to check the Get My Payment tracker or call a phone number at the bottom of the letter if you haven’t received your check.

With the two first stimulus payments, the IRS also sent a confirmation letter in the mail within 15 days of your payment going out — Notices 1444-A and 1444-B. Those two letters could help you claim missing stimulus money on your taxes this year.

If you believe you received the wrong amount — such as if a dependent was skipped — or the total doesn’t match the estimated amount from our stimulus calculator, it could indicate that you need to hunt down your missing money using this letter. The IRS advises you to hold on to the letter for your 2021 tax records. What this really means is that it’s useful if you need to claim missing money in the future, as you could on your 2020 taxes as a recovery rebate credit for the first two checks.

Here’s more information on using the recovery rebate credit worksheet to figure out the credit from the first two checks that you can claim on your 2020 taxes if you haven’t filed yet. You’ll enter the total amount you determine you’re owed on line 30 of the 2020 1040 (PDF) or 1040-SR (PDF) tax forms.

Does the IRS have my current home address on file?

The IRS would have mailed a notice to your last known address with information on your payment. You’ll need to inform the IRS and USPS if you’ve moved. The IRS needs to independently have your correct information on file.

The IRS continues to send out third stimulus payments.
Sarah Tew/CNET

What can I do if I lost the IRS letter or never got it?

If you don’t have the IRS confirmation letter, you should be able to 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 agency’s 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. For married couples filing jointly, each spouse will need to log in to their own account.

Can I find my IRS account information online?

The IRS online registration process can take about 15 minutes. During the setup process, the IRS will first email and then text you 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.

Here’s more information about tax season and your stimulus check, everything you need to know about the third stimulus check and some details about when to expect child tax credit payments.