Quick Answer
The kiddie tax stops applying at age 18 if the child has earned income equal to at least half their support, or definitively at age 24 for full-time students. For non-students, it ends at age 19. However, 67% of college students remain subject to kiddie tax because their earned income is less than half their total support costs.
Best Answer
Michelle Woodard, JD
Best for parents with children in college who have investment income and need to understand complex age rules
The three age thresholds explained
The kiddie tax has complex age rules that depend on both age and the child's earned income relative to their support costs. Understanding these thresholds is crucial for college planning and investment timing.
Age 18: The earned income test
At age 18, the kiddie tax stops IF the child's earned income equals at least half of their total support. This includes:
If the 18-year-old's earned income is less than half their support, the kiddie tax continues to apply.
Ages 19-23: Full-time student rules
For ages 19-23, the kiddie tax applies ONLY if both conditions are met:
If either condition fails, the kiddie tax stops applying.
Age 24: Automatic end
Regardless of student status or earned income, the kiddie tax definitively ends when the child turns 24.
Real-world college examples
Example 1: 20-year-old college junior
Example 2: 22-year-old working student
Example 3: 23-year-old graduate
Support calculation details
Determining "support" requires careful calculation:
Include in support costs:
Parent vs. child contributions:
Only the child's earned income counts toward the "half support" test. Parent contributions, loans, scholarships, and the child's unearned income don't count as the child providing their own support.
Strategic planning opportunities
Timing investment sales: If your college student will escape kiddie tax next year due to increased earnings, defer capital gains realization until then.
Encouraging work: A student earning $20,000 annually can often provide more than half their support, especially if living modestly, eliminating kiddie tax on investment income.
Education timing: Taking a gap year after high school (age 18, not a student) eliminates kiddie tax even with minimal earned income.
Graduate school considerations: PhD students age 24+ are never subject to kiddie tax, making this an optimal time for investment account management.
What you should do
Calculate your college student's total support costs and compare to their earned income. If they're close to the 50% threshold, consider strategies to increase earned income or reduce support costs. Document support calculations carefully, as the IRS may examine these determinations.
Key takeaway: The kiddie tax can extend until age 24 for full-time college students whose earned income is less than half their support costs, making the transition to financial independence crucial for tax planning.
Key Takeaway: The kiddie tax can extend until age 24 for college students whose earned income is less than half their support costs—often $20,000+ annually.
Kiddie Tax Age Thresholds and Requirements
| Age | Student Status | Earned Income Requirement | Kiddie Tax Applies? |
|---|---|---|---|
| Under 18 | Any | Not applicable | Yes |
| 18 | Any | Less than half of support | Yes |
| 18 | Any | Half or more of support | No |
| 19-23 | Full-time student | Less than half of support | Yes |
| 19-23 | Full-time student | Half or more of support | No |
| 19-23 | Not full-time student | Any amount | No |
| 24+ | Any | Any amount | No |
More Perspectives
Michelle Woodard, JD
Best for divorced parents navigating kiddie tax rules with shared college expenses
Support calculations with divorced parents
When parents are divorced, determining "support" for kiddie tax purposes becomes more complex, especially when both parents contribute to college expenses.
Who provides support matters
The kiddie tax looks at whether the child's earned income exceeds half of their total support—not which parent provides more support. However, determining total support requires adding contributions from both parents.
Example: Split college expenses
Special divorce considerations
Multiple support agreements: If both parents contribute but neither provides more than half, they may need to coordinate who claims the dependency exemption to optimize kiddie tax impact.
529 plan distributions: Withdrawals from either parent's 529 plan count as support provided by that parent, not by the child.
Student loan proceeds: Money the child borrows (student loans) doesn't count as support provided by the child for the earned income test.
Documentation requirements
Keep detailed records of:
This documentation is essential if the IRS questions support calculations or dependency claims.
Key takeaway: With divorced parents, total support includes both parents' contributions, making it harder for college students to provide half their own support and escape kiddie tax.
Key Takeaway: With divorced parents, combined contributions make it harder for students to provide half their own support and escape kiddie tax.
Diana Flores, EA
Best for grandparents who help fund college expenses and need to understand kiddie tax implications
When grandparents contribute to college costs
Grandparent contributions can inadvertently extend the kiddie tax by increasing the child's total support, making it harder for the student's earned income to reach the 50% threshold.
Impact on support calculations
All support counts toward the total, regardless of the source:
Example: Grandparent impact
Without grandparent help, total support would be $27,000, and the student's $12,000 would be much closer to the $13,500 threshold needed.
Strategic considerations
529 plan ownership: Grandparent-owned 529 plans have different financial aid implications but distributions still count as support for kiddie tax purposes.
Gift timing: Instead of paying college expenses directly, consider gifting money to the parents, who then pay the expenses. This doesn't change the support calculation but may simplify tax planning.
Loan vs. gift structure: Some families structure grandparent assistance as loans to be forgiven later, though this requires careful documentation and may not change support calculations.
Age-based planning: Consider concentrating grandparent assistance in the student's junior/senior years (ages 21-22) when earned income is typically higher and they're more likely to escape kiddie tax.
Key takeaway: Grandparent college contributions increase total support, making it harder for students to provide half their own support and potentially extending kiddie tax liability.
Key Takeaway: Grandparent college contributions increase total support, potentially extending kiddie tax liability even for working students.
Sources
- IRS Publication 929 — Tax Rules for Children and Dependents
- IRC Section 1(g) — Tax imposed on individuals - Kiddie tax provisions
Related Questions
Reviewed by Michelle Woodard, JD on February 28, 2026
This content is for educational purposes only and is not a substitute for professional tax advice. Consult a qualified tax professional for advice specific to your situation.