Kakutei Shinkoku: the income tax return in Japan

Have you ever wondered how to declare income tax in Japan, or how to claim a refund? For residents, that return is called kakutei shinkoku [確定申告]. It settles shotokuzei, the national income tax.

Many employees never file one. The company withholds tax through the year and settles the difference in December and January. Keep every slip from that season. You file when that adjustment never happened, when salary or other income crosses a line the company cannot close, or when you want a deduction that the company forms left out.

People who have to file normally have from 16 February to 15 March of the following year. For 2025 income, 15 March 2026 fell on a Sunday, so the National Tax Agency accepted returns through 16 March 2026. A refund-only return can be sent from 1 January of the following year, and the claim stays open for five years.

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Who has to file

On the National Tax Agency's list for wage earners, filing is required unless the only result would be a refund. These are the cases:

• Salary for the year is over 20 million yen. That figure is earnings, before the employment-income deduction. A salary over 20 million yen sits outside year-end adjustment.
• You had one employer, tax was withheld, and your other income is over 200,000 yen. Leave employment income and retirement income out of that 200,000 yen, and use income after expenses. The profit on a freelance fee is what counts, and it can be smaller than the payment that reached the bank. Rent can fall in the same place.
• You had two or more employers, each of them withheld tax, and the salaries that missed year-end adjustment plus that other income come to more than 200,000 yen. Count the secondary job as earnings. You can skip the return when those salary earnings, after subtracting the deductions other than casualty losses, medical expenses, donations and the basic exemption, are 1.5 million yen or less, and the other income is 200,000 yen or less.
• You are a director of a family company, or a relative of that director, and you receive loan interest or rent from the company.
• Withholding was postponed under the Disaster Exemption Act.
• The person who pays you has no duty to withhold income tax.
• Tax on a retirement allowance, worked out in the ordinary way, would come out higher than the tax already withheld from it.

Dividends and listed-share gains that you have chosen to leave off the return, and interest already taxed separately at source, stay outside that 200,000 yen total. A part-time job, an arubaito, follows the same money line: the pay that missed the company adjustment is what matters. Leaving one company in the middle of the year works the same way if the next employer could not adjust the whole year. Self-employed income has no company adjustment, so you report the income and the expenses on this form.

When the return is a refund

Medical bills, a dependent, a housing loan and premiums you paid yourself are common reasons to file even when the list above leaves you out. The National Tax Agency calls that a refund claim, kanpu shinkoku [還付申告]. You receive money back only when tax was already withheld. A withholding slip that shows zero has no income tax to hand back.

Medical costs count when you paid them between 1 January and 31 December for yourself or for a relative who shares your household. The deduction starts from what you paid, takes off anything insurance reimbursed, then takes off 100,000 yen. If your total income is under 2 million yen, that last subtraction is 5 percent of total income. The deduction stops at 2 million yen. You submit a medical-expense statement, or a notice from the insurer, and you keep the receipts for five years because the tax office can ask to see them. A separate self-medication route covers certain over-the-counter medicines, with a 12,000 yen floor and an 88,000 yen cap. You choose one route for the year.

A dependent counts for this income-tax deduction from age 16, and only while that person's own total income stays under the ceiling. For 2025 income the ceiling was 580,000 yen, or 1,230,000 yen of salary if salary was all they had. For 2026 income, the National Tax Agency's year-end sheet sets it at 620,000 yen of total income, or 1,360,000 yen of salary when salary is the only income. The 380,000 yen ceiling belongs to an older rule.

A relative living abroad needs papers, and age changes which papers. From 16 to under 30, and from 70 upward, the office wants proof of the relationship and proof of money sent for living costs or school. From 30 to under 70, the National Tax Agency still allows the deduction in three situations: the person is studying abroad, the person has a disability, or you sent at least 380,000 yen that year for living costs or education and can show the transfers. That 380,000 yen tests the remittances, which is a different test from the income ceiling above.

If you paid kokumin kenko hoken [国民健康保険] or national pension premiums yourself, and the employer left those amounts out of the year-end adjustment, you can deduct the premiums on the return. A mortgage, or a dependent the company already listed, can stay on the company forms. File when you are claiming a housing-loan credit for the first time, or when a dependent was missing from the adjustment.

Gensen choshu and the year-end adjustment

Employees usually see income tax leave the monthly salary. The name for that withholding is gensen choshu [源泉徴収]. At the end of the year the employer runs nenmatsu chosei [年末調整]. It compares the tax already withheld with the tax on a full year of salary, then returns the excess or collects the shortfall in the December or January pay. The slip that records the year is the gensen choshuhyo [源泉徴収票]. Since 1 April 2019 you no longer have to attach that slip, or show it when you hand the form in. You still need the numbers on it to fill the form, so take it with you.

Dependents can go on the forms the company collects for withholding. Once they are on those forms, this deduction does not need a separate return. Leaving a dependent off the forms is one reason the tax stays higher than it should. If the family changed after the adjustment, you correct the year on the return.

What to take, and where it goes

Before you file, gather the papers that match your own case:

1. The withholding slip from each employer, for the figures.
2. A My Number card, which is the practical key for e-Tax. At a counter, a residence card (zairyu card) or a passport shows who you are. The residence card replaced the old alien-registration certificate.
3. The medical-expense statement, if you are claiming that deduction, with the receipts kept at home.
4. Dependent papers: a birth or marriage record when the office asks for someone in Japan, and the relationship and remittance documents for someone abroad.
5. Proof of national health insurance, national pension or other premiums paid outside payroll.
6. The bank account for a refund: bank name, account type and account number.
7. Housing-loan papers in the year you first claim that credit.

A personal seal, an inkan, still turns up on older checklists. e-Tax with a My Number card accepts the return without a seal. At a temporary desk, the staff will say whether they want one that day.

You submit the form to the tax office, the zeimusho [税務署], for your address. City hall often hosts a temporary desk during the season, sometimes with staff who can help in another language. The filing itself still belongs to that tax office. If your Japanese is up to the screens, e-Tax through the National Tax Agency's preparation corner sends the return from home, including from a smartphone with a My Number card. A certified tax accountant, a zeirishi [税理士], can take the filing when the income comes from a business or the papers for a relative abroad are hard to sort.

Put the December and January slips where you can find them in February. If the company adjusted the year and none of the duties above fit you, there is nothing you must send. A deduction the company left out can still be claimed for 2025 income through 31 December 2030. The dependent ceiling already moved between that return and the 2026 year-end sheet, so a figure from a few years ago needs a check against the current National Tax Agency page before you rely on it.