Is it true that "if you support your child, you can claim the dependent deduction at any age"?

“If you support your child, you can get the dependent deduction no matter how old they are.” Do you think so?

When year-end adjustment (nenmatsu chōsei) season comes around, some people take this at face value and write the names of all their children on the declaration form. The idea is that each name written makes the tax lower. However, whether the dependent deduction applies is not decided only by whether you support the person. The statute draws clear lines for age and for income. The age line exists at the bottom (age 16), but not at the top.

First, let us sort out the terms.

Four tax terms, explained first

Here are plain-language explanations of the terms used in this article.

• Dependent deduction (fuyō kōjo) = an amount that can be subtracted from your income according to the number of family members you support
• Dependent (fuyō shinzoku) = a relative recognized for tax purposes as someone you support. There are four conditions
• Qualifying dependent (kōjo taishō fuyō shinzoku) = a dependent who is aged 16 or over as of December 31 of the year. There is no upper age limit
• Total income (gōkei shotoku kingaku) = the total of a year’s profits. It is a different figure from gross receipts

Conclusion

Our verdict is “False.” The “at any age” in “if you support your child, at any age” does not match the statute. The lower age limit is 16, and there is also an income condition. However, there is no upper limit, and an adult child also qualifies if the conditions are met.

The statute sets the scope at “aged 16 or over”

The amount of the dependent deduction is set out in Article 84 of the Income Tax Act.

居住者が控除対象扶養親族を有する場合には、その居住者のその年分の総所得金額、退職所得金額又は山林所得金額から、その控除対象扶養親族一人につき三十八万円（その者が特定扶養親族である場合には六十三万円とし、その者が老人扶養親族である場合には四十八万円とする。）を控除する。 ［1］

(Income Tax Act, Article 84, paragraph 1. The quotation is in the original Japanese.)［1］

Put plainly, it says this. The dependent deduction can be used only when you have a “qualifying dependent.” The amount is ¥380,000 per person, ¥630,000 for a specified dependent (tokutei fuyō shinzoku), and ¥480,000 for an elderly dependent (rōjin fuyō shinzoku).

So who is a qualifying dependent? Article 2 of the same Act defines it.

控除対象扶養親族　扶養親族のうち、次に掲げる者の区分に応じそれぞれ次に定める者をいう。イ　居住者　年齢十六歳以上の者 ［2］

(Income Tax Act, Article 2, paragraph 1, item 34-2. The quotation is in the original Japanese.)［2］

Put plainly, for people living in Japan the line is “aged 16 or over.” Even a dependent does not become a qualifying dependent until they reach 16.

For people living in Japan, the only age the statute sets is “16 or over.” No upper limit is written. At 70 and over, the person becomes an “elderly dependent” and the amount changes, but they do not drop out of the deduction.

Children under 16 are not covered

The National Tax Agency (NTA) draws the same line in its explanation.

控除対象扶養親族とは、扶養親族のうち、その年12月31日現在の年齢が16歳以上の人をいいます。 ［3］

(NTA Tax Answer "No.1180 Dependent deduction." The quotation is in the original Japanese.)［3］

In other words, for a child aged 15 or under, writing their name on the declaration form does not increase the dependent deduction. However, the “matters concerning inhabitant tax” section of the form does have a place to write dependents under 16［11］.

Does that mean there is nothing for children under 16? No. There is the child allowance (jidō teate), which is paid in cash.

支給対象児童（0歳から18歳に達する日以後の最初の3月31日までの間にある子をいいます。以下同じ。）を養育している方 ［4］

(Children and Families Agency, "Guide to the child allowance system." The quotation is in the original Japanese.)［4］

The child allowance is not an income deduction. It is a cash payment, and it is not taxed when you receive it.

The amount changes in three steps by age

Even within the same dependent deduction, the amount changes with the child’s age. Adding the ages from the statute to the NTA’s table gives the following.

(Table in NTA Tax Answer "No.1180 Dependent deduction.")［3］

Only the fourth row of the table is based on the Act on Special Measures Concerning Taxation. Article 84 of the Income Tax Act does not contain this addition. When an elderly dependent is a lineal ascendant who lives with you, ¥100,000 is added.

居住者の有する所得税法第二条第一項第三十四号の四に規定する老人扶養親族が当該居住者又は当該居住者の配偶者の直系尊属で、かつ、当該居住者又は当該配偶者のいずれかとの同居を常況としている者である場合には、当該老人扶養親族に係る同法第八十四条第二項に規定する扶養控除の額は、同条第一項の規定にかかわらず、同項の金額に十万円を加算した額とする。 ［5］

(Act on Special Measures Concerning Taxation, Article 41-16, paragraph 1. The quotation is in the original Japanese.)［5］

The highest amount is not for the high-school age group. It is ¥630,000 for a specified dependent aged 19 to under 23. In years when you have a child aged 19 to 22, the deduction rises considerably.

Most children turn 19 by December 31 of the year they finish high school, and the ¥630,000 applies from that year (from the following year for those born between January 1 and April 1). The age cut-off is decided only by age as of December 31, not by entering university or starting work.

Adult children also qualify if the conditions are met

For children living in Japan, the dependent deduction is set only at “16 or over,” and there is no upper age limit. Even after reaching adulthood at 18, a child is a qualifying dependent as long as they meet the conditions for a dependent.

年齢十八歳をもって、成年とする。 ［10］

(Civil Code, Article 4. The quotation is in the original Japanese.)［10］

The amount of the dependent deduction changes in three steps by age.

• Age 18 (before turning 19): ¥380,000 as a general qualifying dependent
• Ages 19 to 22: ¥630,000 as a specified dependent
• Age 23 and over: ¥380,000 as a general qualifying dependent

A child who went on to graduate school, a child who started work but earns little, or a child who works part-time also qualifies if these conditions are met. If their total income is ¥620,000 or less (for 2026) and they live on the same household budget as the parent, the ¥380,000 deduction is available even at 23 or over.

Conversely, once the child starts working, earns more, and their total income exceeds ¥620,000, they fall outside the dependent deduction. For ages 19 to under 23, the special deduction for specified relatives (tokutei shinzoku tokubetsu kōjo; total income over ¥620,000 and up to ¥1,230,000, for 2026) remains. An amount depending on the child’s total income, up to ¥630,000, can be deducted. However, this deduction does not exist for ages 23 and over［9］.

For children living abroad, there are separate age rules. A non-resident dependent qualifies only if aged 16 to under 30, aged 70 or over, or aged 30 to under 70 and studying abroad, a person with a disability, or receiving ¥380,000 or more in payments for living or education expenses［3］. For children living in Japan, there is no upper age limit.

There are conditions other than age

Does being 16 or over always qualify? Not quite. The dependent deduction is not decided only by “whether you support the person.” It is decided by whether all four conditions for being a dependent in the first place are met.

扶養親族とは、その年の12月31日（納税者が年の中途で死亡しまたは出国する場合は、その死亡または出国の時）の現況で、次の4つの要件のすべてに当てはまる人です。 ［3］

(NTA Tax Answer "No.1180 Dependent deduction." The quotation is in the original Japanese.)［3］

The four conditions are as follows.

(The four conditions in NTA Tax Answer "No.1180 Dependent deduction.")［3］

The third line, for income, has been moving from year to year. In a note, the NTA explains that the amount rises from 2026.

（注）令和8年12月1日に施行され、令和8年分から適用される金額は「62万円以下」です。 ［3］

(Note in NTA Tax Answer "No.1180 Dependent deduction." The quotation is in the original Japanese.)［3］

The NTA explains the ¥580,000 condition as employment income (salary) of ¥1,230,000 or less［3］. The salary amount after the rise to ¥620,000 is not given on that page. In the year-end adjustment for 2026, the test is whether total income is ¥620,000 or less.

Families with a child who has started a part-time job need to check every year whether this line has been crossed. Even if a child aged 19 to under 23 has total income over ¥620,000, they qualify for the special deduction for specified relatives if it is ¥1,230,000 or less［9］.

Age is counted on December 31, not on the birthday

A child who turns 16 during the year qualifies from that year. Conversely, a child in the same school year but born later does not qualify for that year.

Even if A and B are in the same school year, the treatment differs if their ages differ at year-end. Before filling in the declaration for dependents’ deduction (fuyō kōjo-tō shinkokusho), check each child’s age as of December 31.

Article 85 of the Income Tax Act provides that whether a person is a dependent is judged by the circumstances as of December 31［6］. In the year-end adjustment, that judgment is made based on the circumstances on the day the employer makes the last salary payment［7］. However, even in the year-end adjustment, age is counted as of December 31［9］.

A child who turns 16 during December also qualifies from that year’s year-end adjustment. In a final tax return as well, age is judged as of December 31［6］.

What to do

1. Check each child’s age as of December 31 of the year
2. Check whether total income is ¥620,000 or less (for 2026; ¥580,000 or less for 2025, and ¥480,000 or less for 2024 and earlier)
3. Write children who are 16 or over and meet the conditions on the declaration for dependents’ deduction used in the year-end adjustment. The same applies to adult children
4. Children under 16 are not covered by the dependent deduction, so writing them does not increase the income tax deduction. However, do write them in the inhabitant tax section of the form［11］
5. If income rises and total income exceeds ¥620,000, the child is not covered by the dependent deduction for that year

The declaration you submit to your employer for the year-end adjustment is provided for in Article 194 of the Income Tax Act.

国内において給与等の支払を受ける居住者は、その給与等の支払者（その支払者が二以上ある場合には、主たる給与等の支払者）から毎年最初に給与等の支払を受ける日の前日までに、次に掲げる事項を記載した申告書を、当該給与等の支払者を経由して、その給与等に係る所得税の第十七条（源泉徴収に係る所得税の納税地）の規定による納税地（第十八条第二項（納税地の指定）の規定による指定があつた場合には、その指定をされた納税地。以下この節において同じ。）の所轄税務署長に提出しなければならない。 ［8］

(Income Tax Act, Article 194, paragraph 1. Filing when there is a change during the year is under paragraph 3 of the same Article. The quotation is in the original Japanese.)［8］

Employees are required to submit this declaration by the day before their first salary payment each year. If the number of children you support increases, or a child graduates and earns more, you file it again even in the middle of the year［8］. The NTA form is called the “declaration (of change) for dependents’ deduction” (fuyō kōjo-tō (idō) shinkokusho)［9］.

Summary

The “at any age” in “if you support your child, at any age” does not match the statute. The dependent deduction applies to qualifying dependents aged 16 or over as of December 31; children under 16 are not covered. Besides age, all the other conditions, such as the income condition, must also be met.

On the other hand, there is no upper age limit. An adult child is also covered by the dependent deduction if they live on the same household budget and have total income of ¥620,000 or less. Before filling in the declaration, check two things: age and income. If you are unsure, consult the tax office or a licensed Japanese tax accountant (zeirishi).

出典

• ［1］所得税法第84条（扶養控除）— e-Gov法令検索　確認日：2026-10-25
• ［2］所得税法第2条（定義）— e-Gov法令検索　確認日：2026-10-25
• ［3］No.1180 扶養控除— 国税庁　確認日：2026-10-25
• ［4］児童手当制度のご案内— こども家庭庁　確認日：2026-10-25
• ［5］租税特別措置法第41条の16（同居の老親等に係る扶養控除の特例）— e-Gov法令検索　確認日：2026-10-25
• ［6］所得税法第85条（扶養親族等の判定の時期等）— e-Gov法令検索　確認日：2026-10-25
• ［7］所得税法第190条（年末調整）— e-Gov法令検索　確認日：2026-10-25
• ［8］所得税法第194条（給与所得者の扶養控除等申告書）— e-Gov法令検索　確認日：2026-10-25
• ［9］給与所得者（従業員）の方へ（令和8年分）— 国税庁　確認日：2026-10-25
• ［10］民法第4条（成年）— e-Gov法令検索　確認日：2026-10-25
• ［11］令和8年分 給与所得者の扶養控除等（異動）申告書（PDF）— 国税庁　確認日：2026-10-25

Note: This article is based on laws and official information as of October 25, 2026. It is a translation of the Japanese original; if the two differ, the Japanese version prevails. Quotations from laws and official sources are given in the original Japanese, followed by unofficial reference translations. Sources are based on laws (e-Gov) and official materials of the NTA, all in Japanese. If a correction is needed after publication, a correction record will be added at the end of this article (Correction policy).