TL;DR
- ✅ Under 17 at year end: $2,200 in Step 3
- ✅ 17 or older at year end (still your dependent): $500 in Step 3
- ✅ Age counts on December 31, so update at the start of the year they turn 17
- ✅ Skipping the change under-withholds by $1,700 per child
How the amounts change
| Child's age on December 31 | Credit | Enter in Step 3 |
|---|---|---|
| Under 17 | Child tax credit | $2,200 |
| 17 or older, still your dependent | Credit for other dependents | $500 |
| No longer your dependent | None | $0 |
A worked example
A family has a 16-year-old who turns 17 in March and a 13-year-old. Last year Step 3 was $2,200 + $2,200 = $4,400. This year the older child counts at $500, so Step 3 should be $500 + $2,200 = $2,700. Leaving $4,400 in place means withholding is about $1,700 too low for the year, and that spreads over the paychecks you have left, so the earlier you change it the less it costs per paycheck.
Recalculate Step 3 for your family — free
Enter your dependents and their ages to see the right amount for Step 3.
Open the W-4 Calculator →⚠️ Two parents, one set of kids
Only one parent should claim the children in Step 3, so change it on that parent's W-4. If both work, see the W-4 for couples who both work and W-4 Step 3: claiming dependents.
Related changes at the same stage
- Single parent who qualifies for head of household: head of household W-4.
- Your child starts their first job: W-4 for college students and first jobs.
- Had a baby instead: W-4 after having a baby.
- Not sure how much extra to withhold: the Step 4(c) guide.
Frequently asked questions
What happens to the child tax credit when my child turns 17?
A child must be under 17 at the end of the tax year to qualify for the $2,200 child tax credit. In the year your child turns 17, you get the $500 credit for other dependents instead, if they still qualify as your dependent.
When should I update my W-4?
Before the tax year in which your child turns 17, or as early in that year as you can. The credit is based on age on December 31, so even a child who turns 17 in December counts as 17 for the whole year.
What do I put in Step 3 for a 17-year-old?
$500 for each dependent who is 17 or older, instead of $2,200. A family with one 17-year-old and one 12-year-old enters $2,700 ($500 + $2,200).
Do I still claim a college student or an older child?
Yes, if they are still your dependent. A full-time student under 24 who you support can qualify as a dependent, and they count at $500 in Step 3. A dependent over the age limit with low income may also qualify as a qualifying relative.
What if I do not update it?
Step 3 will still count $2,200 for that child, so your employer withholds $1,700 too little over the year for that child. You may owe at tax time, and you may owe a penalty if the shortfall is large.
Key terms in this article
Related guides
W-4 Step 3: Claim Dependents and the $2,200 Child Credit (2026)
Step 3 directly reduces your withholding for every qualifying child and dependent. Here's exactly what to enter.
W-4 After Having a Baby: What to Enter in Step 3 (2026)
Enter $2,200 per child in Step 3, decide which spouse claims it, and see how much more you take home each paycheck.
How to Fill Out a W-4 as Head of Household (2026)
Who qualifies, which box to check, and how the larger standard deduction and your dependents change withholding.
W-4 for Married Couples 2026: How to Fill It Out When Both Spouses Work
Two incomes, two W-4s. Filing status, the Step 2 choice, and which spouse claims the kids, so you do not owe in April.
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