My 21 year old daughter and her 8 month old son life with me fulltime, i pay all expenses as she has not worked, can i file hoh for grandson as depend if she claims him?

[xmasbaby0]

If your daughter has not worked or received any taxable income she has nothing to gain by claiming a dependent.  The refundable child-related credits like earned income credit and additional child tax credit are based on having income from working,  If she did not work she will not be eligible for those credits and will not get an income tax refund.

If she had less than $4700 of income and you provided over half the support for your daughter and your grandchild, you can file as HOH and claim both of them as dependents.   You will be eligible for refundable child-related credits if you worked.

IRS interview to help determine who can be claimed:

https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent

WHO CAN I CLAIM AS A DEPENDENT?

You can claim a child, relative, friend, or fiancé (etc.) as a dependent on your 2023 taxes as long as they meet the following requirements:

Qualifying child

• They're related to you.
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They're under the age of 19 (or 24 for full-time students).
• No age limit for permanently and totally disabled children.
• They lived with you for more than half the year (exceptions apply).
• They didn't provide more than half of their own support for the year.

Qualifying relative

• They don't have to be related to you (despite the name).
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They lived with you the entire year (exceptions apply).
• They made less than $4,700 in 2023.
• You provided more than half of their financial support.

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them. There may be other tax benefits you can get when you claim a dependent.

Related Information:

• What does "financially support another person" mean?
• What is a "qualifying person" for Head of Household?

Am I Head of Household?

https://ttlc.intuit.com/questions/1894553-do-i-qualify-for-head-of-household

https://ttlc.intuit.com/questions/2900097-what-is-a-qualifying-person-for-head-of-household

If you qualify as Head of Household, when you enter your marital status (single or married filing separately) into MyInfo, and then enter your qualifying dependent, TurboTax will offer HOH as your filing status.

[Opus 17]

"can i file hoh for grandson as depend if she claims him?"

No.  The dependent can't be split in this way.  Either you claim your granddaughter as a dependent and claim all the benefits, or your daughter claims her child as a dependent and claims all the benefits.  And you can't file as HOH without a qualifying dependent.

If your daughter has not worked, it is likely that you will get a larger tax benefit from claiming your grandchild than your daughter will.  You may also be able to claim your daughter as a dependent.  The only way to know for sure which has the greatest tax benefit is to prepare test returns with different scenarios.