Kiddie Tax on Children's Unearned Income: 2025 Thresholds & Filing

When your child receives dividend income from an inherited brokerage account or interest from a trust, the IRS doesn't tax that income at the child's typically low rate. Instead, the "kiddie tax" rule (Section 1(g) of the tax code) captures unearned income above a threshold and taxes it at your marginal tax rate—often 24%, 32%, or 35%—rather than the child's 10% or 12% bracket. For 2025, any unearned income above $2,700 can be taxed as if it were yours, shifting hundreds or thousands of dollars in tax liability to a higher rate.

This rule exists to prevent wealthy parents from sheltering income by putting investments into children's names. However, the mechanics of kiddie tax—and when to use Form 8615 (the automatic calculation) versus Form 8814 (an election to report the child's income on your own return)—confuse many filers. Combined with updated 2025 thresholds and age eligibility rules, the planning opportunity is both significant and time-sensitive.

The Three-Tier Income Structure for 2025

The kiddie tax rule creates a three-tier treatment of unearned income. The first $1,350 of a child's unearned income is not taxed at all in 2025—this is the standard deduction floor for a dependent with only unearned income. The next $1,350 (from $1,351 to $2,700) is taxed at the child's own rate, typically 10% or 12%, if they have no other income. Any unearned income above $2,700 is taxed at the parent's marginal tax rate.

These thresholds are indexed annually for inflation. In 2024, the thresholds were $1,300 and $2,600; in 2025, they increased to $1,350 and $2,700. If your child's total unearned income (dividends, interest, capital gains, rental income, annuity distributions) stays below $1,350, there is no federal tax at all. At $1,350 to $2,700, the child pays tax at their own rate. Once it exceeds $2,700, the excess falls into your bracket—and that's where the tax bill suddenly spikes.

Worked Example: A 14-Year-Old with $6,200 in Dividend Income

Suppose your 14-year-old daughter inherits a stock portfolio from her grandmother's trust. The portfolio generates $6,200 in qualified dividend income in 2025, and she has no other income. Under the kiddie tax rule, here's how the IRS taxes it:

• First $1,350: Zero federal income tax (covered by the standard deduction).
• Next $1,350 (from $1,351 to $2,700): Taxed at her rate. If she's in the 10% bracket (and she is, since her total taxable income is only $1,350), this tier costs her 10% × $1,350 = $135.
• Remaining $3,500 ($6,200 − $2,700): Taxed at your rate. If you're in the 24% federal bracket (married filing jointly, $89,075–$190,750 income), this portion costs 24% × $3,500 = $840.

Total federal tax on $6,200 of dividend income: $135 + $840 = $975. If the dividends had been taxed at her rate throughout, the bill would be $6,200 × 10% = $620 (after the $1,350 standard deduction). The kiddie tax rule adds $355 to her federal liability because of the $3,500 portion taxed in your 24% bracket instead of her 10%. This is why the rule matters: income crossing the $2,700 threshold suddenly becomes far more expensive.

Who Qualifies as a Child for Kiddie Tax Purposes

The IRS applies kiddie tax to a "child" under two distinct age pathways. The first category covers children under 18 at the end of the tax year—so a child turns 18 on December 25, 2025, and is still subject to kiddie tax for that year. The second category extends the rule to full-time students under 24 at year-end, provided they don't provide more than half their own support (room, board, tuition). A college student funded partly by scholarships and partly by parental support can still trigger kiddie tax if total parental aid exceeds 50% of their annual costs.

The rule sunsets entirely once the child turns 24 (or finishes full-time student status before 24). At that point, all their unearned income is taxed at their own rate, no matter the amount. This creates a planning opportunity: if a teenager will turn 18 next year and has significant unearned income, the year they turn 18 may be the last year the kiddie tax applies, so accelerating income into that year (or deferring it until they're 18) can shift the tax burden.

Form 8615 vs. Form 8814: Two Paths to Reporting Kiddie Tax

When your child's unearned income exceeds $2,700, you must file either Form 8615 (Kiddie Tax) with the child's return, or you must elect Form 8814 (Parent's Election to Report Child's Interest and Dividends). These are not two ways to do the same thing; they represent fundamentally different filing strategies with different tax outcomes.

Form 8615 is the standard approach. The child files their own return (if required by income), and Form 8615 calculates how much of their unearned income gets taxed at the parent's rate. This requires you to provide your tax data (filing status, taxable income, tax on that income) to calculate the correct rate for the child's excess unearned income. The child's return is filed separately, and the kiddie tax is applied on their form.

Form 8814 is an election—and it's available only if the child has no earned income and their gross income is less than $12,950 (in 2025, the standard deduction plus $450). Under this election, you agree to report the child's interest and dividend income directly on your own tax return instead of filing a separate return for the child. The income adds to your return and is taxed at your bracket, but you avoid filing a return for the child. Form 8814 is most valuable when the child's income is modest and stays under the threshold for requiring their own return, keeping your filing simpler while still applying the kiddie tax correctly.

When Form 8814 Makes Sense Over Form 8615

Choosing Form 8814 over Form 8615 is purely an administrative decision if the child qualifies. If your 16-year-old has $2,800 in interest income from a savings account and no other income, Form 8814 allows you to add $2,800 to your return without filing a separate form for the child. You lose the deduction for investment expenses the child might claim, but if there are none, Form 8814 simplifies your filing and the outcome is identical: the kiddie tax is applied, and the excess over $2,700 (here, $100) is taxed at your rate.

However, Form 8814 becomes unavailable if the child has earned income (such as a summer job), because the kiddie tax rule only applies to unearned income. If your child earned $4,000 from employment plus $3,000 in dividends, the $3,000 in dividends would still be subject to kiddie tax, but Form 8814 is off the table due to the earned income. You'd file Form 8615 instead. Similarly, if the child's total gross income exceeds $12,950, you must file a separate return for them, and Form 8814 is not available. Form 8815 becomes mandatory, and you provide your information to calculate the kiddie tax within the child's return.

Capital Gains and the Net Investment Income Tax

Kiddie tax applies to all unearned income: dividends, interest, capital gains, annuities, and passive rental income. If your child's inherited stocks appreciate and they sell them for a $4,000 long-term capital gain in 2025, that $4,000 counts as unearned income for kiddie tax purposes. The first $1,350 is covered by the standard deduction, the next $1,350 is taxed at the child's rate (typically 0% or 15% for long-term capital gains in a low bracket), and anything above $2,700 is taxed at your rate—potentially at 15% or 20% long-term capital gains rate if you're in a high bracket, or even the 3.8% Net Investment Income Tax (NIIT) if your modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly).

This combination can be devastating. A $10,000 long-term capital gain over the $2,700 threshold means $7,300 taxed as if it were your income. At a 20% capital gains rate plus 3.8% NIIT, the total rate is 23.8%—far higher than the 0% or 15% rate the child would pay on a smaller gain. Planning the timing of gains and losses across multiple years can reduce this burden, but it requires coordinating the child's sales with your own income picture and filing status.

Earned Income and the Earned Income Credit Opportunity

A quirk of the kiddie tax rule is that it applies only to unearned income. If your child works during the summer and earns $5,000 in wages, plus receives $2,000 in dividend income, the $2,000 is subject to kiddie tax (but the $5,000 in wages is not). More importantly, the $5,000 in earned income is their income, taxable at their rate, but it doesn't trigger kiddie tax even if their total income is $7,000.

Some parents deliberately encourage their children to earn W-2 wages to offset unearned income. A 16-year-old with $6,000 in dividend income and $6,000 in earned income from a summer job would have $12,000 in total income. The $6,000 dividend is subject to kiddie tax, but the $6,000 wage fills the child's standard deduction ($12,950) and can generate an Earned Income Credit (EIC) of up to $560 for a qualifying child. The EIC directly reduces tax liability and can even produce a refund, sometimes offsetting the kiddie tax burden on the dividends.

Filing Deadlines and Common Mistakes

If your child is required to file a return and unearned income exceeds $2,700, Form 8615 must be attached to their return (or Form 8814 must be filed with yours). Missing this form is a common error: the IRS will calculate the tax as if the child's entire income was taxed at their own rate, and the child pays less than they should. The IRS typically catches this during processing and bills the child for the difference, plus interest and potentially penalties. Filing correctly on the first return avoids this headache.

The standard deadline is April 15, 2026, for 2025 tax returns. However, if you file for an extension (Form 4868), your child's return deadline also extends to October 15, 2026. Even so, estimated taxes may be due quarterly if the child's unearned income is substantial. For example, if a child receives $4,000 in annual dividends paid semiannually ($2,000 each), estimated tax vouchers (Form 1040-ES) should be filed by June 15 if the total tax owed is projected to exceed $1,000.

Another mistake is miscalculating the standard deduction when the child has both earned and unearned income. The standard deduction for 2025 is $12,950 for a dependent claimed on a parent's return, but if the child has $6,000 in wages and $2,000 in dividends, the standard deduction doesn't simply zero out the tax. Instead, the standard deduction first applies to earned income, and unearned income is taxed above that, subject to kiddie tax once it exceeds the tier thresholds. Mixing up this calculation—treating all $8,000 as first using the standard deduction—underreports the tax owed on the unearned portion.

Year-End Planning to Minimize Kiddie Tax

If your child is age 17 and will turn 18 on January 1, the year they turn 18 is the last year kiddie tax applies. In the year of the 18th birthday, unearned income over $2,700 is still taxed at your rate. But once they turn 18 (or 24 if still a full-time student after turning 18), all future unearned income is theirs. This creates a planning opportunity: if you control the assets in your child's name (such as a UTMA custodial account), you might accelerate gains or income into the final kiddie tax year if your tax rate is lower than it will be in their adult years, or defer them if your rate is about to spike. Timing a stock sale to occur after the child's 18th birthday could save significant tax if the child is in a 0% capital gains bracket.

Another strategy is to hold appreciated securities in your own name and gift them to the child after they turn 18 or age out of kiddie tax. If you hold the stock and pass it at death, the child receives a step-up in basis and avoids capital gains tax entirely. If you gift it while alive but after kiddie tax ends, any future gains accrue at the child's low rate. The key is timing: give appreciated assets after the kiddie tax window closes, not before.