Japan's Tax Year and Filing Basics: Year-End Adjustment and the Final Tax Return

Learn how Japan's calendar tax year works, why most salaried workers usually do not file a return themselves, and when a final tax return is still needed.

Published October 20, 2026 at 11:08 AM JST | By Tokyo Paul

Quick answer: Japan's income tax year runs from January 1 to December 31. Most salaried employees do not file a return because the employer completes a year-end adjustment (nenmatsu chosei) and settles the tax. A final tax return (kakutei shinkoku) is filed by people with higher salaries, other income above set limits, or a refund to claim, usually between mid-February and mid-March.

The calendar tax year

Income tax in Japan is calculated on income earned from January 1 to December 31. There is no separate fiscal year for individuals, so a person's tax picture for 2025, for example, covers exactly the twelve months of 2025, and the return for it is filed early in 2026. The National Tax Agency publishes an English guide each year that sets out this timing and explains the rules in plain terms.

Residency matters for how much income is counted. The agency's guide describes residents as people with a domicile or a residence in Japan for one year or more, and says they are taxed on their whole income. Non-permanent residents are taxed on Japan-source income plus foreign-source income that is paid in or sent to Japan. Non-residents are taxed only on income from Japanese sources.

Withholding through the year

Employees do not wait until year end to pay. Each month the employer withholds income tax from salary at source, using a standard estimate of what the annual tax will probably be. This is why a pay slip shows a deduction for income tax even though no return has been filed. The amount withheld is a running estimate, not the final figure.

Because the estimate cannot know everything about a person's year, a settling-up step is needed at the end. Dependents, insurance premiums, and other deductions can change the real tax bill, and a person may also change jobs or earn extra money. Japan handles this settling-up in one of two ways: through the employer's year-end adjustment, or through the person's own final tax return.

How year-end adjustment works

Year-end adjustment (nenmatsu chosei) is the employer's yearly recalculation of an employee's income tax. The employer compares the tax withheld during the year with the tax that should apply to the actual annual salary and the deductions the employee has declared. Any excess is refunded, usually through a pay slip, and any shortfall is collected. The National Tax Agency notes that most wage earners do not need to file a final return because the employer completes this process.

In practice, employees are typically asked to hand in forms in the autumn that list dependents, insurance premiums, and similar items, and the adjustment is usually carried out near the end of the year. Exact schedules and forms differ by employer, so the personnel or payroll department is the best source for dates.

Who still needs a final tax return

Some salaried people must file even though an employer has done the year-end adjustment. According to the National Tax Agency's English page for wage earners, the main cases include salary above 20 million yen, a single employer plus other income (not counting employment or retirement income) above 200,000 yen, and several employers where other income and secondary employment income together exceed 200,000 yen. Directors of family companies who receive loan interest or rent from the company are also listed.

Other categories exist, such as people whose withholding was postponed after a disaster, or people paid by a payer that is not required to withhold. Because the conditions have exceptions, it is worth reading the agency's page for the exact wording, or asking the local tax office. Freelancers and business owners file as a matter of course, since no employer settles their tax for them.

Filing a return to claim a refund

A return can also be filed by someone who is not required to. The National Tax Agency explains that wage earners can file when the tax already withheld or prepaid is more than the tax calculated on their annual income. Common examples on its refund page include leaving a job partway through the year without a year-end adjustment, claiming a housing loan credit, and claiming medical expense or donation deductions.

The refund page also states that a refund request can be submitted for up to five years from January 1 of the following year, which means a missed claim is often not lost. Documents such as the withholding slip from the employer, receipts, and certificates for deductions are what the tax office typically asks for, so keeping them in one folder makes the process much easier.

Filing period and how to file

For income earned in 2025, the National Tax Agency's English guide gave a filing window of February 16 through March 16, 2026. In most years the end date is March 15, and a notice from Minato City explains that when the date falls on a weekend or public holiday, the due date moves to the following day (March 15, 2026 was a Sunday). Anyone expecting a refund is encouraged to file before the busy period starts.

Returns can be filed through the online e-Tax system, by post, or in person at the tax office or a temporary reception venue set up for the season. Local notices often suggest bringing a smartphone and a My Number Card for the online route. The agency's yearly guide and the local tax office list the current dates, so check them before planning.

Resident tax and practical tips

Resident tax (juminzei) is a separate local tax paid to the prefecture and the municipality. A city guide from Toshima describes it as calculated on the previous year's income and owed by people living in the municipality on January 1. It is paid either by deduction from salary, usually from June to May of the following year, or by the person directly in installments. This is why a bill can arrive in the second year of work, and why it can still arrive after someone leaves Japan.

Useful habits include keeping the employer's year-end withholding slip, noting any mid-year job change, and asking the tax office early if anything is unclear. This guide shares general information; rules change, so confirm details with the official agency or provider before you act.

Frequently Asked Questions

Do I have to file a tax return if my employer does the year-end adjustment?

Usually not. The National Tax Agency says most wage earners do not need to file because the employer completes the calculation. A return is required in specific cases, such as salary above 20 million yen or other income above 200,000 yen, so check the agency's page for the full list that applies to your situation.

When is the final tax return due?

For 2025 income the filing window ran from February 16 to March 16, 2026. In most years the deadline is March 15, moving to the next weekday when it falls on a weekend or holiday. Dates are announced each year, so confirm the current period with the National Tax Agency or the local tax office.

Can I get a refund after the year-end adjustment?

Sometimes. A refund return can be filed for items the employer could not handle, such as medical expense deductions, donations, or a first-year housing loan credit. The National Tax Agency says refund requests can be made for up to five years from January 1 of the following year, so a late claim may still be possible.

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