The current child tax credit was $1,000 per child under the age of 17.
The credit was reduced by $50 for each $1,000 a taxpayer earns over certain thresholds. The phase-out thresholds started at a modified adjusted gross income (AGI) over $75,000 for single individuals and heads of household, $110,000 for married couples filing jointly and $55,000 for married couples filing separately.
New Rule (Effective January 1, 2018)
The child tax credit doubles to $2,000 per qualifying child. Up to $1,400 of the child tax credit can be received as refundable credit (meaning it can go toward a tax refund). The new rule also includes a $500 nonrefundable credit per dependent other than a qualifying child.
The credit begins to phase out at an AGI over $200,000 — for married couples, the phase-out starts at an AGI over $400,000.
This rule is in effect through 2025.