How the Child Tax Credit Calculator works
This tool applies the standard federal Child Tax Credit (CTC) formula for the 2024 tax year, using the tests and figures set by the Tax Cuts and Jobs Act rules currently in effect: a per-child credit amount, a smaller credit for other dependents, a phase-out tied to modified adjusted gross income (MAGI), and a partially refundable Additional Child Tax Credit (ACTC) for families whose credit exceeds their tax bill.
Step 1: the tentative credit
Start with $2,000 for every qualifying child under age 17 at year-end, plus $500 for every other dependent (the nonrefundable Credit for Other Dependents, or ODC) — a 17-or-older child, a parent, or another relative you support who doesn't meet the qualifying-child tests.
Tentative credit = (children × $2,000) + (other dependents × $500)
Step 2: the MAGI phase-out
If your modified AGI is above $200,000 (single, head of household, or married filing separately) or $400,000 (married filing jointly), the combined credit is reduced by $50 for every $1,000 — or part of $1,000 — of MAGI over that threshold, down to a floor of $0.
Reduction = ceiling(excess MAGI ÷ $1,000) × $50
Step 3: nonrefundable vs. refundable
The phased credit first offsets your tax liability dollar-for-dollar as a nonrefundable credit. If your tax bill is smaller than the credit, the leftover child-credit portion (the $500 other-dependent credit is never refundable) can be claimed as the refundable Additional Child Tax Credit, subject to two caps: $1,700 per qualifying child for 2024, and 15% of earned income above $2,500.
ACTC = min(unused child-credit portion, $1,700 × children, 15% × (earned income − $2,500))
Worked example
A single filer with 2 qualifying children, no other dependents, $150,000 MAGI, a $6,000 tax liability, and $90,000 of earned income: the tentative credit is $4,000 (2 × $2,000). MAGI is below the $200,000 threshold, so there's no phase-out. The $6,000 tax liability fully covers the $4,000 credit as a nonrefundable amount, leaving $0 refundable — the family's total tax benefit is $4,000, all applied to reduce taxes owed.
What moves the credit most
- Number of qualifying children: each additional child under 17 adds $2,000 to the tentative credit before any phase-out.
- MAGI relative to the threshold: once you cross $200,000 (or $400,000 MFJ), every extra $1,000 of income costs $50 of credit — a family with a $4,500 combined credit (2 children plus 1 other dependent) phases out entirely about $90,000 above the threshold.
- Tax liability and earned income: a low tax bill relative to the credit only helps if earned income is high enough to unlock the refundable ACTC; both the $1,700-per-child cap and the 15%-of-earned-income test can limit the refund.
Assumptions and limits
This calculator uses 2024 federal figures ($2,000 CTC, $500 ODC, $1,700 ACTC cap per child, $200,000/$400,000 phase-out thresholds) and applies the phase-out proportionally across the child and other-dependent credits before splitting out the refundable amount. It does not model state child tax credits, the interaction with other nonrefundable credits, alternative minimum tax, or prior-year safe-harbor rules. For an official determination, use IRS Schedule 8812 or consult a tax professional.