Helping out with their bills does not necessarily make them your dependents (although it might feel that way)---Are they full-time students?   If your kids were not full-time students then if they had over $4300 of income in 2020 (not counting Social Security) they cannot be claimed as your dependents.

Please see the rules and use the IRS tool to determine whether you can claim them.

WHO CAN I CLAIM AS A DEPENDENT?

You can claim a child, relative, friend, fiance (etc.) as a dependent on your 2019 taxes as long as they meet the following requirements:

Qualifying child

•They are related to you.

•They cannot be claimed as a dependent by someone else.

•They are a U.S. citizen, resident alien, national, or a Canadian or   Mexican resident.

•They are not filing a joint return with their spouse.

•They are under the age of 19 (or 24 for full-time students).

• No age limit for permanently and totally disabled children

  •      They live with you for more than half the year (exceptions apply).

Qualifying relative

•They don't have to be related to you (despite the name).

•They cannot be claimed as a dependent by someone else.

•They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.

•They are not filing a joint return with their spouse.

•They lived with you the entire year.

•They made less than $4300  (not counting Social Security)

•You provided more than half of their financial support. More info

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.

Related Information:

•Does a dependent have to live with me?

•What does "financially support another person" mean?

•Can I claim a newborn baby?

IRS interview to help determine who can be claimed:

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

https://ttlc.intuit.com/questions/3113432-who-can-i-claim-as-my-dependent  

They were both full time students and both made over $4300???  

So do I claim or not?