The Child Tax Credit (CTC) is a federal tax benefit worth $2,000 per qualifying child under age 17. For many families it is one of the largest line items on Form 1040, yet it is easy to underestimate because it shrinks as your income climbs past a phase-out threshold. This calculator models the credit as a transparent formula — $2,000 per child, reduced by $50 for each $1,000 of AGI over the threshold — so you can see exactly what your household is worth before you file.
Enter your earned income, your adjusted gross income (AGI), the number of qualifying children, and your filing status. The result card shows the estimated credit, the gross credit before any phase-out, and how many dollars you are giving back to the phase-out.
How to Use
- Enter your Annual Earned Income — wages from your W-2 plus net self-employment income from Schedule C.
- Enter your Adjusted Gross Income (AGI) from last year's Form 1040. The phase-out is measured against AGI, so this is the number that matters most for high earners.
- Select your Qualifying Children — 0, 1, 2, or 3. A qualifying child must be under age 17 (at the end of the tax year), related to you, and live with you for more than half the year.
- Choose your Filing Status. Single or Head of Household starts the phase-out at $200,000 of AGI; Married Filing Jointly doubles that to $400,000, which is why two-earner couples can often keep the full credit.
- Read the result card. Estimated Credit is the headline number; Gross Credit Before Phase-Out is $2,000 times your children; Phase-Out Reduction shows how much income has clawed back. The Eligibility line prints 1 when the credit is positive (you get money) and 0 when it has been fully phased out to $0 (you owe no credit this year) — read it as "yes, credit applies" versus "no, fully phased out".
How the Credit Is Calculated
Unlike the EITC's three-band ramp, the child tax credit is deliberately simple:
- Base credit. Each qualifying child under 17 is worth $2,000, so a household with N children starts at $2,000 × N.
- Phase-out threshold. The credit begins to decline once AGI exceeds $200,000 for single/head-of-household filers, or $400,000 for married couples filing jointly.
- Phase-out reduction. For each $1,000 (or part of $1,000) of AGI above the threshold, the credit drops by $50. The result is floored at $0 — it never goes negative.
Estimated credit = max(0, $2,000 × children − $50 × ⌈(AGI − threshold) / $1,000⌉)
Worked example: a single filer with 3 children and $210,000 AGI. The base credit is $6,000. AGI exceeds the $200,000 threshold by $10,000, which is 10 chunks of $1,000, so the reduction is 10 × $50 = $500. The estimated credit is $5,500. A filer who stays below $200,000 keeps the full $2,000 per child.
Examples
Example 1 — Two children, modest income. A single parent earns $30,000 with AGI of $30,000. The base credit is $4,000, AGI is far below the $200,000 threshold, so there is no phase-out reduction and the estimated credit is $4,000.
Example 2 — Three children crossing the threshold. A single parent with 3 children reports $210,000 AGI. The base credit is $6,000; $10,000 over the threshold reduces it by $500, leaving $5,500. This matches the standard worked example used in the tax-modeling reference.
Example 3 — Phase-out midpoint. A two-child household with $250,000 AGI and single filing status. The base credit is $4,000; $50,000 over the threshold is 50 chunks of $1,000, reducing the credit by $2,500, leaving $1,500.
Example 4 — High earners get zero. A household earning $1,000,000 with two children, single filer: the $800,000 over the threshold implies a $40,000 reduction, far exceeding the $4,000 base. The calculator clamps the result to $0 and flags the household as not eligible. A married couple at the same income faces a smaller $30,000 reduction (because the joint threshold is $400,000), but still lands at $0.
FAQ
How much is the child tax credit per child?
The base credit is $2,000 per qualifying child under age 17. Up to $1,500 of it is refundable (the additional child tax credit) even if you owe little or no federal income tax; the rest is non-refundable.
At what income does the credit phase out?
For single and head-of-household filers the phase-out starts at $200,000 of AGI; for married couples filing jointly it starts at $400,000. Above that, the credit shrinks by $50 for each additional $1,000 of AGI.
How long does the phase-out last?
It continues in $50-per-$1,000 steps until the credit reaches $0. For two children, that happens $40,000 above the threshold; for three children, $60,000 above. Earnings beyond that earn no credit at all.
Does filing jointly give me a bigger credit?
Yes, indirectly. The joint phase-out threshold is twice the single threshold, so a married couple can earn up to $400,000 before losing any credit, while a single filer starts losing it at $200,000. Within the phase-out band, a couple keeps more of the $2,000-per-child amount.
What counts as a qualifying child?
A child must be under age 17 at the end of the tax year, be your son, daughter, stepchild, foster child, sibling, or descendant of one, live with you in the U.S. for more than half the year, and not provide more than half of their own support. They must also have a valid Social Security number.
What is the difference between this and the EITC?
The Earned Income Tax Credit is an earnings-based subsidy that ramps up with wages, plateaus, then phases out — its size depends heavily on how much you earn. The child tax credit instead starts at a flat $2,000 per child and is only reduced by high AGI. Many working families qualify for both, and they stack.
Disclaimer
This child tax credit calculator is provided for informational purposes only and does not constitute tax, legal, or financial advice. Estimates use illustrative parameters ($2,000 per child, $200,000/$400,000 thresholds, $50 per $1,000 reduction) and are not tied to any specific IRS tax year; the IRS updates these figures annually for inflation and policy changes. Eligibility depends on additional tests including age, relationship, residency, support, and valid Social Security numbers. Always confirm your actual credit with Form 1040 instructions, IRS publications, or a qualified tax preparer before filing.