To help taxpayers reconcile and receive all of the Child Tax Credits to which they are entitled, the IRS will send Letter 6419, 2021 advance CTC, starting late December 2021 and continuing into January. The letter will include the total amount of advance Child Tax Credit payments taxpayers received in 2021 and the number of qualifying children used to calculate the advance payments. People should keep this and any other IRS letters about advance Child Tax Credit payments with their tax records.
Families who received advance payments will need to file a 2021 tax return and compare the advance Child Tax Credit payments they received in 2021 with the amount of the Child Tax Credit they can properly claim on their 2021 tax return.
The letter contains important information that can make preparing their tax returns easier. People who received the advance CTC payments can also check the amount of their payments by using the CTC Update Portal available on IRS.gov.
Eligible families who did not receive any advance Child Tax Credit payments can claim the full amount of the Child Tax Credit on their 2021 federal tax return, filed in 2022. This includes families who don't normally need to file a tax return.
via IRS.GOV IR-2021-255, December 22, 2021