Get your taxes done using TurboTax

1. Please make sure that your child is entered as a dependent on your 2021 tax return before going to the Recovery Rebate section (click on "My Info" on the left and scroll down to review your dependents).

You can only claim the third stimulus payment on your 2021 tax return if you qualify:

1. After entering all your information click "Search" at the top right and type "Stimulus".
2.  Follow the jump to link (if you do not qualify for the Recovery Rebate Credit the stimulus questions will not come up). 
3. On the screen "Let's double-check the amount you received" you will be asked about the amount of third stimulus payment you received. TurboTax will then calculate the amount of stimulus payment remaining that you are still entitled to get. 
4. Any stimulus amount remaining due to you will show as The Recovery Rebate Credit on line 30 of Form 1040.

Please see What are the eligibility rules for the Recovery Rebate Credit? for additional information.

You will have to file an amended 2020 tax return (1040-X) to possibly qualify for the missing first and second stimulus pay. Please see How do I amend my 2020 return?

2. No, to claim a refund, you must file Form 1040-X within 3 years after the date you filed your original return or within 2 years after the date you paid the tax, whichever is later.

Also, please be aware, "you may not claim your child as a qualifying child for the Child Tax Credit if your child doesn't have an SSN before the due date of your return (including extensions), even if your child later gets an SSN" (IRS). The same applies for the Earned Income Credit.