年末調整 (Year-End Adjustment) Explained for Foreigners

What is 年末調整? ねんまつちょうせい

年末調整 (nenmatsu chōsei) literally means "year-end adjustment." It is the process by which your employer reconciles the income tax they withheld from your paychecks throughout the year with the actual tax you owe for that year. Think of it as Japan's built-in alternative to filing a personal tax return — designed so that most salaried employees never have to deal with the tax office directly.

Here is how it works. Every month, your employer withholds an estimated amount of income tax (源泉徴収 / gensen chōshū) from your salary. These monthly estimates are based on standardized tax tables and your declared number of dependents, but they are just that — estimates. They do not account for insurance premiums you paid, changes to your family situation during the year, or other deductions you are entitled to.

At the end of the year (typically in November-December), your employer collects a few forms from you, plugs in the real numbers, and calculates your actual annual tax liability. The difference between what was withheld and what you actually owe is then adjusted in your December payslip — usually as a refund, but sometimes as an additional charge if too little was withheld.

This system is one of the reasons Japan has a much lower rate of individual tax filings compared to countries like the US or UK. The government designed it so that employers act as intermediaries, handling the bulk of tax calculations on behalf of their employees. For most 正社員 (full-time employees) and 契約社員 (contract employees), 年末調整 is the only tax process they ever encounter.

Documents you need 必要書類

Your employer will ask you to submit three key forms (sometimes combined into two physical sheets) plus any supporting certificates. These forms are typically distributed in October or November, with a deadline to return them by late November. Here is what you need to know about each one.

Form 1: 扶養控除等（異動）申告書

ふようこうじょとう（いどう）しんこくしょ — Declaration of Dependents

This is the most important form and the one you likely filled out when you first joined your company. It declares your personal details, your dependents (spouse, children, elderly parents), and your disability status if applicable. Your employer uses this to determine how many dependent deductions (扶養控除) you qualify for, which directly affects your tax withholding.

• ● Your name, address, マイナンバー — basic personal information
• ● Spouse details — if your spouse earns under approximately ¥1.03M/year (giving you 配偶者控除)
• ● Dependent children — ages 16+ qualify for 扶養控除 (¥380,000-¥630,000 deduction depending on age)
• ● Other dependents — elderly parents you support, including those living overseas

Form 2: 保険料控除申告書

ほけんりょうこうじょしんこくしょ — Declaration of Insurance Premium Deductions

This form is where you declare any private insurance premiums you paid during the year. Around October, your insurance companies will mail you certificates (控除証明書) showing the premiums you paid. You attach these certificates to this form.

• ● 生命保険料控除 — life insurance premiums (up to ¥120,000 deduction across three categories: general life, medical/nursing, personal pension)
• ● 地震保険料控除 — earthquake insurance premiums (up to ¥50,000 deduction)
• ● 社会保険料控除 — any social insurance premiums you paid yourself (not through your employer), such as 国民年金 payments from before you joined the company
• ● 小規模企業共済等掛金控除 — iDeCo (個人型確定拠出年金) contributions are declared here and are fully deductible

Form 3: 基礎控除申告書 兼 配偶者控除等申告書 兼 所得金額調整控除申告書

きそこうじょしんこくしょ — Combined declaration for basic deduction, spouse deduction, and income adjustment deduction

This combined form (often printed on one sheet of paper) handles three deductions at once. The most important for most people is the basic deduction section, which simply asks for your estimated total income for the year. For the vast majority of employees, this results in the standard ¥480,000 basic deduction.

• ● 基礎控除 — ¥480,000 for everyone earning under ¥24M. Just write your estimated annual income.
• ● 配偶者控除 / 配偶者特別控除 — fill in if your spouse has income. The deduction amount phases out as their income increases.
• ● 所得金額調整控除 — only applies if your salary exceeds ¥8.5M AND you have a dependent child under 23 or are disabled. Most people skip this section.

Step-by-step: completing your 年末調整 手順

Here is the typical timeline and what you need to do at each stage. Most companies handle this between October and December.

1. October: Collect your insurance certificates. Insurance companies mail you 控除証明書 around October. These small certificates show how much you paid in premiums during the year. Gather them in one place — you will need to attach them to your forms.
2. Late October / Early November: Receive forms from HR. Your company's payroll or HR department will distribute the three forms described above, either on paper or through a digital system (many companies now use SmartHR, freee, or Money Forward for paperless 年末調整).
3. Fill in Form 1 (扶養控除等申告書). Update your personal details, confirm or change your dependents. If nothing changed since last year, just verify the information is still correct and sign.
4. Fill in Form 2 (保険料控除申告書). Copy the figures from your insurance certificates (控除証明書) onto the form. Calculate the deduction amounts using the formulas printed on the form — or let the digital system calculate them automatically. Attach the original certificates.
5. Fill in Form 3 (基礎控除申告書). Write your estimated total income for the year. If you only have one employer, this is straightforward — estimate your total salary for the year. Check the appropriate box for your basic deduction amount (¥480,000 for most people).
6. Submit everything to HR by the deadline. This is usually late November, but your company sets the specific date. Do not miss it — if you do, your employer cannot include your deductions in the year-end adjustment, and you will need to file 確定申告 yourself.
7. December: Check your December payslip. Your employer processes the adjustment and reflects it in your December (or sometimes January) payslip. Look for a line showing the adjustment amount — it is typically a refund.

What you can claim via 年末調整 年末調整で申告できる控除

年末調整 handles a wide range of deductions. If all your deductions fall into the categories below, you do not need to file 確定申告. Your employer settles everything for you.

What you CAN'T claim via 年末調整 (need 確定申告) 確定申告が必要な控除

年末調整 is powerful, but it does not cover everything. The following deductions and credits can only be claimed by filing your own 確定申告 (tax return). If any of these apply to you, you will need to file — even if your employer completed 年末調整.

A practical rule: if your only deductions are the ones your employer already handles (basic deduction, dependent deduction, insurance premiums, iDeCo), then 年末調整 is all you need. But the moment you want to claim medical expenses, donations, or have income outside your main job, you enter 確定申告 territory.

Reading your December payslip adjustment 12月の給与明細の見方

After your employer completes 年末調整, the result appears on your December payslip (or occasionally January). Here is what to look for and how to interpret the numbers.

Your December payslip will typically show a line labeled 年末調整 or 年調過不足税額 (nenchō kafusoku zeigaku). This is the adjustment amount — the difference between the total tax your employer withheld during the year and the actual tax you owe after applying all deductions.

• ● Positive amount (refund): Your employer withheld too much tax during the year. The overpayment is returned to you, increasing your December take-home pay. This is the most common result — typical refunds range from ¥5,000 to ¥50,000 depending on your deductions.
• ● Negative amount (additional charge): Your employer did not withhold enough tax. This can happen if you received a large bonus, had a significant salary increase mid-year, or your dependent status changed. The shortfall is deducted from your December pay.

After 年末調整 is complete, your employer will also issue a 源泉徴収票 (gensen chōshūhyō / withholding tax certificate) — a summary document showing your total annual income, deductions claimed, and total tax paid. Keep this document safe. You will need it if you ever need to file 確定申告, apply for a loan, or prove your income for visa purposes.

Common questions for foreigners 外国人向けの注意点

年末調整 can be confusing for anyone, but foreigners face additional complexities around overseas family, mid-year arrivals, and worldwide income. Here are the scenarios we see most often.

What if I arrived mid-year?

If you started working in Japan partway through the year, your employer will still perform 年末調整 — but only for the income earned at that company. If you had a previous employer in Japan during the same year, you should provide your 源泉徴収票 from that employer so the current one can combine the totals. If your previous income was earned overseas, it generally does not need to be included in 年末調整 (but may need to be reported via 確定申告 depending on your tax residency status).

What about overseas income?

年末調整 only covers your Japanese employment income. If you have income from overseas — such as rental income from property in your home country, dividends from foreign stocks, or freelance payments from overseas clients — these are not part of 年末調整. You will need to report overseas income separately via 確定申告. Note that your obligation to report depends on your tax residency status: non-permanent residents (in Japan less than 5 of the last 10 years) are only taxed on overseas income that is remitted to Japan; permanent residents are taxed on worldwide income. (所得税法第7条)

What if I have side income (副業)?

Your employer's 年末調整 only adjusts tax for the salary they pay you. If you earn side income — teaching English on weekends, freelance translation, online content creation, etc. — and that income exceeds ¥200,000 in a year, you are required to file 確定申告 separately. Even below ¥200,000, you may need to file a 住民税 return at your ward office. Your employer does not know about your side income, so it is your responsibility to report it.

The forms are all in Japanese — what do I do?

This is a real challenge. The 年末調整 forms are only available in Japanese, and there are no official English translations. Here are your options: (1) if your company uses a digital HR system like SmartHR, some have English language settings; (2) ask a bilingual colleague to help you the first time — once you have done it once, it is largely the same every year; (3) use FinBuddy's form guides to understand each field; (4) use your phone's camera translation feature to translate the forms in real time. The good news is that the forms are highly standardized, so the same fields appear in the same places every year.

Frequently asked questions よくある質問