I actually claimed 3 children. And only got credit for 2

[Critter]

If one is over the age of 16 then you only get the $500 credit for them not the $2000 one ... review the entire return with the worksheets to see how things are calculated. 

[amfraz89]

All of my children are under the age of 5

[GiseleD]

To determine if you were able to claim all three dependents, the easiest way is to check the forms. Here's how to look at your current year return forms:

• In the left-hand menu bar, click on Tax Tools, then click Tools.
• Under Other helpful links, click View Tax Summary.
• Your Tax Summary will be displayed. In the left-hand menu bar, you will see a new option: Preview My 1040. Click it, and this will allow you to see the forms.

Yow will want to look at #1 on your 1040 to verify that all your dependents were listed. Next, look at #4 to verify that they were all eligible for the Child Tax Credit. If you see that not all were eligible for the Child Tax Credit, review your entries in the My Info section of the return (left-hand menu bar in TurboTax Online) to check for errors. 

@amfraz89

[Critter]

The child tax credit is on different lines, on the 2019 form 1040, than it was on the 2018 form.  See item #4 below.

 There are 6 possible reasons; you aren’t getting the Child Tax credit (CTC). It’s usually #4:

1. You’ve entered something wrong. In the personal Info section, for the dependent, you must select answers that indicate that he/she is your dependent child. If the child was born during the year, say he/she lived with you all year (note: TurboTax changed how this section is done two years ago, you may need to go thru the interview again or even delete your dependent and start over). If the child was born in 2018, you have to answer that he lived with you all year. The CTC is not an automatic $2000, per child. It is income dependent. If you haven't entered your income yet, the CTC will not show.
2. Your child may be too old (over 16). You can still claim your child. What you can't claim is the Child tax credit. This comes as a big surprise to many parents the year their child turns 17. A child over age 16 no longer qualifies for the Child Tax credit (CTC). Although a child can still be a student dependent through age 23, and a qualifying child for EIC, the Child Tax Credit expires the year they turn 17 and you no longer get the $2000 CTC.
3. Your income is too high. The Child Tax Credit (CTC) is phased out at higher incomes starting at $400,000 for joint filers ($200K single). You lose $50 for each $1000 (rounding up) your income is over that threshold.
4. Your income is too low. The child tax credit (CTC) is also limited to your tax liability. The CTC is a non-refundable credit and can only reduce your income tax to 0, It can not help you beyond eliminating your tax liability. But, if you have more than $2500 of earned income, some or all of it is usually given back to you thru the "Additional Child tax credit". That is, part of the CTC may be on line 18b of form 1040 (2019 version) instead of line 13a (lines 17 and 12 in 2018).   The  ACTC is calculated on form 8812 and  is basically 15% of your earned income over $2500. The ACTC is a maximum of $1400 per child (not $2000).
5. You are the custodial parent and the non-custodial parent is claiming the dependent this year. The CTC goes with the dependency, even though the custodial parent still gets the Earned Income Credit, Dependent care credit and Head of Household.
   6. Another possibility is that part of your tax due is not regular income tax, but is self-employment, early distribution penalty or another type of additional tax, for which the CTC cannot be used.

There has been lots of hype in the news about the new $2000 Child Tax Credit.  Unfortunately, some people do not yet understand that it does not mean they will automatically receive $2000 per child just for filing a tax return.

Do not assume your refund will include $2000 per child for child tax credits.  It does not work that way.  The CTC is used first to reduce your tax liability to zero. After that, there is a refundable portion —up to $1400 — called the Additional Child Tax Credit that is calculated based on the amount of income you earned.  You do not necessarily get the maximum amount.  You get 15% of the amount of income earned above $2500--UP to the maximum amount possible.