The Child Tax Credit (CTC) is one of the largest federal tax breaks available to American families with children, and in 2024 it is worth up to $2,000 per qualifying child under age 17 — plus $500 for each other dependent. Yet the credit is not automatic for everyone: it phases out as income rises, and only part of it is refundable, which means many parents over- or under-estimate what they will actually receive. This calculator walks through the IRS formula step by step — gross credit, income phase-out, non-refundable tax offset, and the refundable Additional Child Tax Credit (ACTC) — so you can plan your 2024 filing with real numbers instead of guesswork.
Adjust the sliders and every figure updates instantly. Switch your filing status, nudge your AGI upward, or add a child, and watch the phase-out reduction appear the moment your income crosses the threshold.
How to Use
- Pick your Filing Status. Married filing jointly (MFJ) receives a phase-out threshold of $400,000; single, head of household, and married filing separately all use $200,000.
- Enter your 2024 Adjusted Gross Income (AGI) from Form 1040. This is the number that triggers the phase-out, not your gross wages.
- Count your Qualifying Children Under 17. Each one must be a US citizen, national, or resident alien, live with you more than half the year, and be claimed as your dependent.
- Add Other Dependents — relatives or children age 17+ who do not qualify for the full $2,000 credit but still count for the $500 Credit for Other Dependents.
- Leave Credit per Qualifying Child at $2,000 unless you are estimating an earlier tax year, when the amount differed.
- Set Income Tax Before Credits to your expected 2024 tax liability. The calculator uses this to split the CTC into the part that lowers your tax bill and the refundable part paid to you even if you owe no tax.
The result card first shows your Gross Credit — the full amount before any phase-out. It then compares your AGI to the threshold, computes the $50-per-$1,000 reduction, and displays the CTC After Phase-out, the non-refundable portion applied against your tax, and the refundable ACTC. The bottom line, Total Tax Savings / Refund, is the dollar amount that actually reaches your pocket.
The CTC Formula, Step by Step
The Internal Revenue Service publishes the CTC rules in Publication 972. The math is straightforward:
- Gross credit = ($2,000 × qualifying children) + ($500 × other dependents).
- Phase-out threshold = $400,000 if MFJ, otherwise $200,000.
- Excess over threshold = max(0, AGI − threshold).
- Reduction = ⌈excess ÷ $1,000⌉ × $50, capped at the gross credit. The IRS rounds up to the next full $1,000 — so earning $1 over the threshold still costs you $50.
- CTC after phase-out = gross credit − reduction (never below zero).
- Non-refundable portion = min(CTC after phase-out, your income tax before credits).
- Refundable ACTC = CTC after phase-out − non-refundable portion. In 2024, the refundable portion is capped at $1,700 per child and limited by the 15%-of-earned-income floor above $2,500; this calculator shows the theoretical refund before applying those IRS caps.
Worked example: a married couple earning $80,000 with two qualifying children has a gross credit of $4,000. Their AGI is well below the $400,000 threshold, so no phase-out applies. If their tax before credits is $6,000, the full $4,000 wipes out part of the tax bill and nothing is refundable.
How the Phase-out Actually Bites
The phase-out is gentle at first but relentless. Every additional $1,000 of income above the threshold costs a family $50 of credit. On MFJ returns with two children ($4,000 gross), the credit disappears entirely once AGI reaches $480,000 — $80,000 above the threshold. A family with four children ($8,000 gross) can earn up to $560,000 before the credit is gone. The key insight: the phase-out is a cliff that is actually a long, shallow slope, and each child pushes the cliff $40,000 further out.
The $50-per-$1,000 rule is deliberately not rounded down. Earning $201 of extra income in a marginal year can still trigger a full $50 reduction because the IRS rounds up to the next $1,000 increment. This is why careful year-end planning — deferring a bonus, making a pre-tax retirement contribution, or bunching medical expenses — can preserve thousands of dollars in credit for families hovering just under the threshold.
Examples
Example 1 — A typical middle-class family. A married couple files jointly, earns $80,000, and has two children under 17. Their gross credit is $4,000, there is no phase-out, and with a tax liability of $6,000 the full $4,000 offsets tax. Total savings: $4,000.
Example 2 — Partial phase-out. A married couple earns $415,000 and has three children. Their gross credit is $6,000. They are $15,000 over the $400,000 threshold, which the IRS rounds to $20,000, producing a $1,000 reduction? Actually the ceiling rule applies: $15,000 ÷ $1,000 = 15 increments, × $50 = $750 reduction, leaving a CTC of $5,250.
Example 3 — Zero children, one dependent parent. A single filer earning $50,000 claims an elderly parent as a dependent. No qualifying children means $0 from the main CTC, but the $500 Credit for Other Dependents still applies, for a total credit of $500.
Example 4 — High earner, fully phased out. A married couple earning $1,500,000 with four children. Their gross credit is $8,000, but they are $1,100,000 over the MFJ threshold. The reduction works out to $55,000, which is clamped to the $8,000 gross credit — so the CTC is $0.
FAQ
What is the 2024 Child Tax Credit amount?
For tax year 2024, the CTC is worth $2,000 per qualifying child under age 17. Up to $1,700 of that per child is refundable (the Additional Child Tax Credit, or ACTC). Dependents who do not qualify for the main credit — such as a child age 17 or an elderly parent — earn a separate $500 Credit for Other Dependents.
At what income does the Child Tax Credit phase out?
The phase-out begins at $400,000 for married filing jointly and $200,000 for all other filing statuses (single, head of household, married filing separately). The credit is reduced by $50 for every $1,000 of income above the threshold, rounded up to the next $1,000.
Is the Child Tax Credit refundable?
Partially. The CTC is primarily a non-refundable credit that reduces your tax bill dollar for dollar. Any amount you cannot use because your tax is too low becomes the refundable Additional Child Tax Credit (ACTC), capped at $1,700 per child for 2024. Families with little or no tax liability can still receive a refund through the ACTC, subject to the earned-income rules in IRS Publication 972.
Who counts as a qualifying child?
A qualifying child must be: (1) under age 17 by the end of the year, (2) a US citizen, US national, or US resident alien, (3) claimed as your dependent, (4) have lived with you for more than half the year, and (5) not have provided more than half of their own financial support. Children born or dying during the year generally still qualify if the residency tests were met.
What is the difference between CTC and ACTC?
The Child Tax Credit (CTC) is the full $2,000 per child. The Additional Child Tax Credit (ACTC) is the refundable portion — the amount of the CTC you receive as a refund because your tax liability is too low to absorb the full credit. In other words, the ACTC is not a separate credit; it is the spillover from the CTC.
How do I claim the credit if my income is below the threshold?
If your AGI is below the $200,000 or $400,000 threshold, no phase-out applies and you receive the full gross credit for your children. You simply report the number of qualifying children on Schedule 8812 and attach it to Form 1040. The calculator above will show the full amount with a $0 phase-out reduction.
Does the CTC affect my 2025 refund estimate?
This calculator is calibrated to 2024 rules ($2,000 per child, $400k/$200k thresholds). For 2025, confirm the latest amounts on IRS.gov before filing, because Congress has occasionally adjusted the credit. You can override the per-child amount in the inputs to model prior or future years.
Disclaimer
This Child Tax Credit calculator is provided for informational purposes only and does not constitute tax, legal, or financial advice. Estimates are based on 2024 IRS rules from Publication 972 and are simplified; the refundable ACTC is subject to additional caps (15% of earned income above $2,500, $1,700 per-child ceiling) that this calculator does not fully model. Always verify your credit, residency tests, and filing position with a qualified tax professional or directly with the IRS before submitting Form 1040 and Schedule 8812.