Recently, Congress revamped the so-called “kiddie tax” under the Tax Cuts and Jobs Act (TCJA). Congress had enacted the tax rules to prevent parents and grandparents in high tax brackets from shifting income (especially from investments) to children in lower tax brackets.

What changed? The kiddie tax rate structure was the only thing revised by the TCJA. The rest of the kiddie tax rules are the same as before. Here’s what you need to know about how this tax can come into play under the new law.

Important note: For simplicity, throughout this article we use the terms “child” and “children” to apply to both children and young adults under age 24 who may be subject to the kiddie tax.

Kiddie Tax Basics

The TCJA revises the kiddie tax rules to tax a portion of a child’s net unearned income at the rates paid by trusts and estates for 2018 through 2025. For ordinary income, these rates can be as high as 37% or, for long-term capital gains and qualified dividends, as high as 20%.

The trust and estate tax rate structure is unfavorable because the rate brackets are compressed compared to the brackets for single individuals. In other words, the kiddie tax rules can override the lower rates that would otherwise apply to an affected child’s unearned income.

By comparison, the kiddie tax rules under prior law taxed a portion of an affected child’s unearned income at the parent’s marginal tax rate if that rate was higher than the child’s rate. For 2017 for ordinary income, the parent’s rate could be as high as 39.6% or, for long-term capital gains and dividends, as high as 20%.

Important note: For purposes of the kiddie tax rules, the term “unearned income” refers to income other than wages, salaries, professional fees and other amounts received as compensation for personal services rendered. Examples of unearned income include capital gains, dividends and interest. Earned income from a job or self-employment isn’t subject to the kiddie tax.

The child is allowed to deduct his or her standard deduction when calculating the federal income tax bill for a child who’s subject to the kiddie tax. For 2018, if the TCJA hadn’t passed, the standard deduction for a child for whom a dependent exemption deduction would have been allowed under prior law is the greater of:

• $1,050, or
• Earned income plus $350, not to exceed $12,000.

For 2018, the kiddie tax potentially affects children who don’t provide over half of their own support in 2018 and who live with their parents for more than half of the year.

The Age Factor

The kiddie tax can potentially apply until the year that a child turns age 24. And more specifically, the kiddie tax applies when all four of the following requirements are met for the tax year in question:

1. One or both of the child’s parents are alive at the end of the year.

2. The child doesn’t file a joint return for the year.

3. The child’s net unearned income for the year exceeds the threshold for that year, and the child has positive taxable income after subtracting any applicable deductions, such as the standard deduction. The unearned income threshold for 2018 is $2,100. If the unearned income threshold isn’t exceeded, the kiddie tax doesn’t apply. If the threshold is exceeded, only unearned income in excess of the threshold is hit with the kiddie tax.

4. The child falls under one of the following age-related rules:

Rule 1. The child is 17 or younger at year end.

Rule 2. The child is 18 at year end and doesn’t have earned income that exceeds half of his or her support. (Support doesn’t include amounts received as scholarships.)

Rule 3. The child is age 19 to 23 at year end and 1) is a student, and 2) doesn’t have earned income that exceeds half of his or her support. A child is considered to be a student if he or she attends school full-time for at least five months during the year. (Again, support doesn’t include amounts received as scholarships.)

Kiddie Tax in the Real World

To help you understand who could be hit with the kiddie tax after the changes made by the TCJA, here are several examples:

Adam will be 17 on December 31, 2018. So, he falls under Rule 1 (above). For 2018, he will be subject to the kiddie tax if the other three requirements are also met.

Claire is 19 on December 31, 2018. She’s not a student for 2018, so Claire is exempt from the kiddie tax for 2018.

Beth will be 19 on December 31, 2018. She doesn’t have any earned income for the year, and she’s a full-time student for the entire year. She falls under Rule 3. For 2018, she will be subject to the kiddie tax if the other three requirements are also met.

Dennis will be 21 on December 31, 2018, and he graduates from college in May 2018. He qualifies as a full-time student, because he’s enrolled for the first five months of the year. Dennis couldn’t find a job after graduation, so he doesn’t provide over half of his own support for the year. Therefore, he’s subject to the kiddie tax for 2018 under Rule 3, if the other three requirements are also met.

Ellie will be 24 on December 31, 2018. Even though Ellie is still enrolled in college, she’s exempt from the kiddie tax for 2018 and all subsequent years, because none of the age-related rules apply to her.

The Mechanics

When calculating the federal income tax bill under the kiddie tax rules, there are four steps.

1. Add up the child’s net earned income and net unearned income.

2. Subtract the child’s standard deduction to arrive at taxable income.

3. Compute tax for the portion of taxable income that consists of net earned income using the regular rates for a single taxpayer.

4. The kiddie tax will be assessed on the portion of taxable income that consists of net unearned income and that exceeds the unearned income threshold. (That threshold is $2,100 for 2018.) Compute kiddie tax for this amount using the rates that apply to trusts and estates.

Let’s look at one of the previous examples to illustrate how to calculate a child’s federal tax bill. Adam (age 17) has $2,000 of earned income from delivering newspapers and $7,000 of unearned ordinary income. His standard deduction is $2,350 ($2,000 of earned income + $350).

Adam’s taxable income is $6,650 ($2,000 + $7,000 − $2,350). The entire $6,650 is treated as unearned income because his $2,350 standard deduction offsets all of his earned income plus the first $350 of his unearned income.

The first $2,100 (the amount up to the kiddie tax unearned income threshold) is taxed at 10% under the regular rates for single taxpayers, resulting in $210 of tax.

The remaining $4,550 of taxable income ($6,650 – $2,100) falls under the kiddie tax rules and is, therefore, taxed at the rates for trusts and estates as follows:

• The first $2,550 is taxed at 10%, resulting in $255 of tax.
• The remaining $2,000 ($4,550 – $2,550) is taxed at 24%, resulting in $480 of tax.

So Adam’s tax bill is $945 ($210 + $255 + $480).

Important note: Without the kiddie tax, all of Adam’s $6,650 of taxable income would have been taxed at 10% under the regular rates for single taxpayers, resulting in only $665 of tax.

Contact Us

If your child or grandchild has significant unearned income, contact Filler or Associates or your tax advisor to identify strategies that will help reduce the kiddie tax for 2018 and beyond.

Under the TCJA the kiddie tax is somewhat easier to calculate, but it can still be confusing. Your children or grandchildren may be hit even harder by the kiddie tax under the new rules, depending on your circumstances.