My gf received the tax credit for our kids but I am claiming them this year. I don't want my return to be sent back by IRS. Can you walk me through this?

[xmasbaby0]

Wait---so did you all live together in 2021?   Do you mean that your GF got the advance child tax credit payments between July and December?   But now you are claiming the children on your own 2021 return?   She has to file a 2021 tax return herself and enter the amount of the advance payments she received.   Depending on her 2021 income, she may or may not have to pay that money back.   

If you are all living together as a family then the children can only be claimed on one of your tax returns, and only one of you can file as Head of Household.   The other one files as Single.

If you are claiming the kids, and you are not married, then you will say you did not receive the advance CTC payments (your GF got them--not you)  ..   You will end up getting the full CTC on line 28 of your tax return.

Each of you has to answer questions about the CTC on your individual tax returns:

Federal>Deductions and Credits>You and Your Family>Child Tax Credit

The IRS is sending out letter 6419 to you.  It will show the amount of advance child tax credit that you received during 2021.  Enter the information from that letter carefully.   

The remaining amount of CTC that you can receive will show up on line 28 of your 2021 Form 1040.   Then it will calculate down to the refund you see on line 35a or the tax due on line 37.

PREVIEW 1040

https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing

Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.

NOTE:   The CTC is indeed a “credit” that can be applied toward any tax liability that you would otherwise have to pay as “tax due”  to the IRS.

For GF:

TurboTax calculates the Repayment Protection.  This determines if a person is required to repay the advance CTC.

What is Repayment Protection?

Repayment protection is an income-based program that reduces the amount of excess advance Child Tax Credit payments you have to repay.

Full repayment protection equals $2,000, multiplied by the following:

• The number of qualifying children that the IRS took into account when estimating your advance Child Tax Credit payments, minus
• The number of qualifying children you’re claiming on your 2021 tax return.

To be eligible for full repayment protection, your adjusted gross income (AGI) for the 2021 tax year must be at or below the following:

• $60,000 if you are married and filing a joint return or if filing as a qualifying widow or widower;
• $50,000 if you are filing as head of household; and
• $40,000 if you are a single filer or you are married and filing a separate return. 

 You won’t qualify for any repayment protection if your modified AGI is at or above the amounts listed below based on the filing status on your 2021 tax return.

• $120,000 if you are married and filing a joint return or if filing as a qualifying widow or widower;
• $100,000 if you are filing as head of household; and
• $80,000 if you are a single filer or are married and filing a separate return.

For information on the definition of modified AGI, see Topic C: Calculation of the 2021 Child Tax Credit. 

[Critter-3]

If you can claim the dependents legally then what happened with your GF has nothing to do with you.  Complete the dependent section of the MY INFO tab slowly and carefully then latter when you get to the point of how much ADVANCE CTC YOU got you will answer NONE since you did not get it she did.   On her return she will need to enter the amount of advance she got even if she will not be claiming the kids this year and she may need to pay back some or all of the advance depending on her income level.

If you are the custodial parent where the child physically lived for more than half the year (183 nights) then:

When you enter the dependent, you say that he/she is "Your child" (not you and your spouse if remarried), 
he/she lived with you the whole year, 
“no” the child did not pay more than half of his/her own support,
"yes", you have a custody agreement, 
and "yes", the other parent is claiming this year.  

That will give you the EIC, Child Care Credit and Head of Household filing status if you otherwise qualify.

The child would be listed as "non-dependent EIC & Dependent Care only".
The other (non-custodial) parent can claim the child’s exemption and child tax credit only and needs a signed 8332 form to do so.

===

There is no such thing in the Federal tax law as 50/50, split, or joint custody.  The IRS only recognizes physical custody (which parent the child lived with the greater part, but over half, of the tax year.  That parent is the custodial parent; the other parent is the noncustodial parent.)

Who can claim the exemption and credits depends on who is the custodial parent. (By the IRS definition of custodial parent for tax purposes - this is not the same as the legal custody that a court might grant.).

The test that the IRS uses to determine the custodial parent is where the child lived for more than 1/2 (or greater part) of the year. The IRS will go so far as to require counting the nights spend in each household - that person is the custodial parent for tax purposes (if exactly equal and more than 183 days - The custodial parent is the parent with the highest AGI, if less than 183 days then neither parent has custody so the child cannot be claimed by either parent). And yes they are that picky.

See Custodial parent and noncustodial parent  under the residency test in Pub 17

https://www.irs.gov/publications/p17#en_US_2017_publink1000170899
 
Only the Custodial parent can claim: (Child would be listed as non-dependent EIC & CC only)
-Head of Household 
-Earned Income Credit
-Child Care Credit

The non custodial parent can only claim: (Child would be listed as dependent)
-The Exemption
-The Child Tax Credit

But only if specifically specified in a pre-2009 divorce decree, separation agreement or the custodial spouse releases the exemption with a signed 8332 form - after 2009 the IRS only accepts a signed 8332 form that must be attached to the non-custodial parents tax return.

Note. If you are the non-custodial parent filing your return electronically, you must file Form 8332 with Form 8453, (U.S. Individual Income Tax Transmittal) for an IRS e-file Return. See Form 8453 and its instructions for more details.  This must be done within 3 days of your e-filed return being accepted by the IRS.

Only one parent may claim the child as a dependent.  Only the parent who claims the child as a dependent can qualify to use an FSA or claim the child and dependent tax credit.  Only the parent who claims the child as a dependent can use the child to qualify for EIC and head of household status.  In short, you can't "split" any of the tax benefits of claiming a dependent.

Usually, the tax benefit will be larger when the parent who earns more claims the child, because they can also claim head of household status.  Sometimes, if the parents who earns less will qualify for EIC, it will be better for the parent who earns less to claim the child (although they can't file as head of household if they pay less than half the overall household expenses, and the other parent must file as single if they don't claim a dependent.). The only way to know in your case is to test different combinations.  

Be aware that in Turbotax, the parent who will claim the child should answer "no" to the question about a custody agreement, because this only applies to a court order between parents who are separated and live apart.  And the parent who will not be claiming the child should not even list them on their return.  The Turbotax interview questions are designed for parents who live apart and share custody and can lead to incorrect tax returns for parents who live together unmarried. Make sure the parent who will claim the child answers that the child lived with them "all year" (which is correct for a newborn) and don't file until you have the child's social security number. 

[NCperson]

@mekyelh <<If you are all living together as a family then the children can only be claimed on one of your tax returns, and only one of you can file as Head of Household.   The other one files as Single.>>

@xmasbaby0 

.....it is possible that NEITHER of you can claim HOH.

to claim HOH, you must be able to satisfy two conditions

1) you contribute more than 50% of the household expenses.  Obviously only one of you can satisfy this condition. Someone has to be paying more than 50%

2) you must claim a qualifying child. (if you and Her are living together and you TWO are the parents of the children, then they are qualifying children of both of you, so not complicated)

So if She claims the children and You are covering more than 50% of the family's expenses, NEITHER of you can claim HOH.  You both have to file SINGLE as neither can satisfy the two conditions.

Strategically, it is best if the parent that is paying more than 50% of the expenses claims the children, so that that parent can take advantage of HOH filing status (and the other parent files SINGLE)

[Mike9241]

if you're not living with your GF only the custodial parent can claim the children unless that person furnishes the noncustodial parent with form 8332 which must be submitted with your return (requiring mailing ) or by use of form 8453