The child tax credit is not new for 2018 - but it will be expanded quite significantly.
In the past, the credit was worth up to $1,000 per child and was split between two credits - one that reduced your tax liability and one that was possibly refundable (added monies to your refund). There was also a phaseout threshold that could reduce or eliminate your CTC (for HOH this started at $75,000).
Now, for 2018, this credit will be worth up to $2,000 per child with up to $1,400 of the credit refundable. But, more importantly for you, is that the credit phaseout threshold has been increased to $200,000 for single and HOH filers ($400,000 for MFJ). So, in the past, you were likely not receiving any CTC in the scenario above, but you would be eligible for the credit now.
Also, keep in mind that a credit is more valuable than a deduction or exemption as a credit reduces your tax liability dollar for dollar. An exemption only reduces the amount of income you pay tax on - so you only save tax liability at your marginal rate. Also, keep in mind the standard deduction will be doubled, which will help make up for the loss of personal exemptions (of course, if you had significant itemized deductions before, then it may not).
There are too many variables on any one tax return to give any definitive answers, but for most taxpayers who are eligible for the revised CTC, the credit will make up for the lack of exemptions and a lot of families will come out better (especially combined with the standard deduction).
However, there are definitely going to be scenarios where this is not the case. The clearest example is if you have children who are NOT under 17 years old (i.e dependents in college). These children would still not qualify for the CTC under the old or new rules. So, now you are losing your personal exemptions for these dependents and not making up for it with the CTC. Another scenario would be those who claimed dependents who are not children like aging parents or other relatives. There is a smaller $500 nonrefundable "family" credit in the new law for these scenarios to help make up the difference, but it may not have the same impact as the prior exemptions.
