Quick answer
A 確定申告 (kakutei shinkoku, final income tax return) is how you yourself report a year's income and the income tax due to the 税務署 (zeimusho, tax office). For most employees, the company's 年末調整 (nenmatsu chōsei, year-end tax adjustment) completes their tax payment, so there is no need to file on their own; but if you have side income, various deductions (medical expenses, housing loan, and so on), or left a job mid-year, you may need to — or may choose to — file yourself. If you overpaid tax and want it refunded, you can file a 還付申告 (kanpu shinkoku, refund return). Whether you need to file, and how, should always follow the National Tax Agency's (国税庁, Kokuzeichō) official guidance.
What this document is
The 確定申告 is Japan's self-assessment filing system for income tax. It commonly involves:
- 確定申告: reporting a year's income, then calculating and paying income tax (with any overpayment refunded or shortfall paid).
- 年末調整: for employees, the company adjusts and completes most of the tax payment at year-end on their behalf.
- 還付申告: a filing made when you want a refund, for example because too much was withheld (it can be submitted later).
The National Tax Agency's 確定申告書等作成コーナー (Kakutei Shinkokusho-tō Sakusei Kōnā, online tax return preparation portal) lets you prepare the return online.
Common fields on the document
- 確定申告書 (kakutei shinkokusho) — the final income tax return form.
- 所得金額 / 課税所得 (shotoku kingaku / kazei shotoku) — amount of income / taxable income.
- 源泉徴収税額 (gensen chōshū zeigaku) — income tax already withheld (see your 源泉徴収票 (gensen chōshū-hyō, withholding tax statement)).
- 各種控除 (kakushu kōjo) — the various deductions (medical expenses, social insurance premiums, dependents, and so on).
- 還付 / 納付 (kanpu / nōfu) — tax refund / tax payment.
- 申告期限 (shinkoku kigen) — the filing deadline.
What you need to do
- First determine whether you need to — or can — file a 確定申告 (side income, deductions, refunds, and other such situations).
- Gather your documents: your 源泉徴収票, supporting documents for each deduction, a bank account (for refunds), and so on.
- Prepare the 確定申告書 using the National Tax Agency's 確定申告書等作成コーナー or on paper, and submit it within the filing period (a refund-only 還付申告 is not limited to the filing period — it can be filed from January 1 of the following year, within the statutory number of years).
- If you are unsure whether you need to file, or have questions about how the amounts are calculated, ask your tax office or refer to the National Tax Agency's guidance.
Possible deadlines / where the amounts come from
- Deadline: the 確定申告 has a fixed annual 申告期限 (a period in spring of the following year); a 還付申告 can be submitted later (within a certain number of years starting from the following year) — follow the National Tax Agency's announcement for the relevant year.
- Amounts: the tax you owe or are owed is calculated from your income and the various deductions, per the National Tax Agency's rules.
Which official body to confirm with when unsure
For whether you need to file, and how to file and calculate, follow the National Tax Agency (国税庁) website and your local 税務署; for company-side 年末調整 matters, ask your company. Official guidance takes precedence over any third-party interpretation.
Common Japanese terms
- 確定申告 (kakutei shinkoku) — final income tax return (self-filed)
- 年末調整 (nenmatsu chōsei) — year-end tax adjustment (handled by the company for employees)
- 還付申告 (kanpu shinkoku) — refund return
- 所得控除 (shotoku kōjo) — income deduction
- 源泉徴収票 (gensen chōshū-hyō) — withholding tax statement
- 申告期限 (shinkoku kigen) — filing deadline