How Schedule 8812 Calculates the Child Tax Credit: Phase-Out Math and Refundable Credit

If you've ever stared at Schedule 8812 and wondered how the IRS turns your number of kids and your income into a dollar figure, you're not alone. For the 2025 tax year, the maximum Child Tax Credit is $2,200 per qualifying child, but almost nobody gets a flat number — the form runs your income through a phase-out test and then splits the credit into a nonrefundable piece and a refundable piece called the Additional Child Tax Credit. This walkthrough follows the actual line-by-line math so you can see exactly where your number comes from.

What Schedule 8812 is actually calculating

Schedule 8812 walks through a sequence of calculations to arrive at your final credit amount. First, it multiplies your qualifying children by the maximum credit to get a starting number before any limits apply. Line 5 of the 2025 form instructs filers to multiply the number of qualifying children on line 4 by $2,200 to get this pre-phase-out credit amount. Second, it checks whether your income is high enough to trigger a phase-out, since the credit begins shrinking once modified AGI exceeds $200,000 for most filers or $400,000 for married couples filing jointly. Third, it compares what's left against your actual tax liability, and whatever credit you can't use against taxes owed may convert into the refundable Additional Child Tax Credit, worth up to $1,700 per qualifying child for 2025. The same schedule also computes the Credit for Other Dependents, worth up to $500 per dependent who doesn't qualify for the CTC — such as a 17-year-old — and that credit phases out under the identical income thresholds.

Worked Example 1: A family under the income threshold

Picture a married couple filing jointly with 2 qualifying children, both under 17 with valid Social Security numbers, modified AGI of $45,000, pre-credit tax liability of $500, and earned income of $45,000, with no other dependents or credits. Since their modified AGI is far below the $400,000 married-filing-jointly threshold at which the CTC and ODC begin phasing out, no phase-out applies to their credit. Their pre-phase-out credit amount on line 8 is 2 qualifying children multiplied by $2,200, which comes to $4,400. But their tax liability is only $500, so they can only use $500 of that $4,400 as a nonrefundable credit against taxes owed — the remaining $3,900 becomes eligible for the refundable Additional Child Tax Credit, subject to the earned-income test and the $1,700-per-child cap, meaning up to $3,400 could be refundable for their two children.

• qualifying children: 2
• Formula: qualifying children*2200
• Result: 4400

Worked example

• qualifying children: 2
• Formula: qualifying children*2200
• Result: 4400

Pre-phase-out credit for a family with 2 qualifying children in 2025.

How the refundable ACTC is actually computed

Schedule 8812 first subtracts $2,500 from your earned income on line 18a, and if your earned income is $2,500 or less, that step produces $0, meaning no refundable credit is available through this formula. The IRS describes this refundable portion as the Additional Child Tax Credit, worth up to $1,700 per qualifying child for 2025.

Worked Example 2: A family above the phase-out threshold

Now consider a married couple filing jointly with the same 2 qualifying children, but modified AGI of $430,000 and tax liability before credits comfortably above $2,900, so the tax-liability limit never comes into play. Their modified AGI of $430,000 exceeds the $400,000 married-filing-jointly threshold by $30,000, and that figure happens to already be an exact multiple of $1,000, so no rounding is needed before the next step. Schedule 8812 reduces the credit by 5 percent of that excess, which works out to the same thing as $50 for every $1,000 over the threshold — in this case, $30,000 times 5 percent produces a $1,500 reduction. Subtracting that $1,500 phase-out from the $4,400 pre-phase-out amount leaves a Child Tax Credit of $2,900, and because this family's tax liability is ample, the full $2,900 is usable as a nonrefundable credit with nothing left over — so they claim $0 of the refundable Additional Child Tax Credit.

Worked example

• magi: 430000
• threshold: 400000
• Formula: magi-threshold
• Result: 30000

Excess income above the married-filing-jointly phase-out threshold.

Worked example

• excess: 30000
• Formula: excess*0.05
• Result: 1500

Phase-out reduction applied to the Child Tax Credit.

Worked example

• line8: 4400
• line11: 1500
• Formula: line8-line11
• Result: 2900

Final Child Tax Credit after the phase-out reduction.

Step	Family 1 (MAGI $45,000)	Family 2 (MAGI $430,000)
Pre-phase-out credit (2 children × $2,200)	$4,400	$4,400
Income over threshold	$0 — below $400,000 threshold	$30,000 over $400,000 threshold
Phase-out reduction	$0	$1,500, equal to 5% of the $30,000 excess
Credit after phase-out	$4,400	$2,900
Refundable Additional Child Tax Credit	Up to $3,400 subject to the $1,700-per-child cap	$0

Key things to remember

• The maximum Child Tax Credit for 2025 is $2,200 per qualifying child, and the refundable Additional Child Tax Credit caps out at $1,700 per child.
• Phase-out begins once modified AGI tops $200,000 (most filers) or $400,000 (married filing jointly); in a hypothetical married-filing-jointly example with modified AGI of $430,000, the $30,000 excess over the threshold produced a $1,500 reduction, equal to 5 percent of the excess.
• The ACTC formula subtracts $2,500 from earned income and multiplies the remainder by 15 percent, then compares that to the per-child cap.
• If you claim the ACTC, your entire refund — not just that portion — is held until mid-February 2026 under federal law for 2025 returns.
• Dependents who don't qualify for the CTC, like teenagers turning 17, may still generate up to $500 through the Credit for Other Dependents under the same phase-out rules.

Common follow-up questions

Does every qualifying child need a Social Security number to count toward the credit?

Yes — the $2,200 maximum credit applies specifically to qualifying children under age 17 at the end of 2025 who have a valid Social Security number.

What happens if my earned income is below $2,500?

If your earned income on line 18a is $2,500 or less, that step of the ACTC calculation produces $0, so you leave line 19 blank and enter zero — meaning the earned-income path to the refundable credit yields nothing that year.

Can I get the Additional Child Tax Credit even if I owe no tax?

The IRS describes the ACTC as the refundable portion of the CTC, available up to $1,700 per qualifying child for 2025, specifically for taxpayers whose tax liability is too low to use the full nonrefundable credit, but the amount actually refunded is also capped by the earned-income formula, which subtracts $2,500 from earned income and produces $0 when earned income is $2,500 or less.

Why does the phase-out math use $1,000 increments?

In Worked Example 2, the family's $30,000 excess over the $400,000 threshold was already an exact multiple of $1,000, and multiplying that $30,000 excess by 5% produced a $1,500 reduction to their Child Tax Credit, the same result as $50 per $1,000 of income over the threshold.

Does a 17-year-old dependent get the same credit as a younger child?

No — a dependent who doesn't meet the CTC's under-17 qualifying-child test instead falls under the Credit for Other Dependents, worth up to $500 and phased out under the same $200,000/$400,000 income thresholds as the CTC.

These two worked examples use hypothetical figures chosen only to illustrate how the phase-out and refundability math works on Schedule 8812 — they are not real taxpayers, and your own result depends on your actual qualifying children, modified AGI, earned income, and tax liability.

Sources

• www.irs.gov
• www.irs.gov
• www.irs.gov
• www.irs.gov