When you leave a job or change jobs, not just your salary but a whole set of tax and social insurance procedures start moving at once. If you change jobs within the same year, everything is settled by your new employer's year-end adjustment; but if you do not find a new job by the end of the year, you have to file a tax return yourself, or you won't get back the tax you overpaid. On top of that, residence tax is "paid later on the previous year's income," so the collection method changes depending on when you leave. This article organizes the tax matters that come with leaving or changing jobs, divided into "withholding tax statement, income tax, residence tax, retirement allowance, and social insurance."
The "withholding tax statement" you receive first is the starting point
When you leave a job, your employer issues a withholding tax statement (gensen-choshu-hyo). This is a record of the salary paid to you that year and the income tax withheld from it, and it is essential for the year-end adjustment at your new job or for filing your own tax return. Be sure to keep it.
Income tax: it splits depending on whether you change jobs within the year or across the year
You changed jobs within the year
If you submit the withholding tax statement from your previous job to your new employer, it will be settled at December's year-end adjustment, combined with the amount from your previous job. In principle, you do not need to file a tax return yourself.
You are not employed by the end of the year
Since no one does a year-end adjustment for you, you file your own tax return the following year. During employment, tax is often withheld at a higher amount, so in many cases you get a refund (a return of the overpayment)[National Tax Agency No.1910].
Salary withholding is calculated on the assumption that you "keep working for the full year." If you leave partway through the year, your total salary and tax end up lower than assumed, and once you reflect the various deductions (basic deduction, social insurance premiums, life insurance premiums, medical expenses, and so on), an overpayment often comes to light.
Residence tax: the collection method changes with the timing of your departure
Residence tax is paid later, from June the following year to May the year after, on the previous year's income[Ministry of Internal Affairs and Communications] (for the mechanism, see How residence tax works and is calculated). While employed, it is deducted from your salary (special collection), but when you leave, this deduction stops, so how the remaining amount is handled changes depending on your month of departure.
| Timing of departure | Treatment of the remaining residence tax |
|---|---|
| Leaving between January 1 and April 30 | Lump-sum collection from your final salary or retirement allowance, up to the May installment. This is the employer's duty, not something you can choose[Local Tax Act, Article 321-5(2) (in Japanese)] |
| Leaving between May 1 and May 31 | The May installment is the last one, so there is no remaining balance and lump-sum collection does not arise |
| Leaving between June 1 and December 31 | Switches to ordinary collection (you pay yourself with payment slips). Lump-sum collection is also possible if you wish |
You will often see this explained as "leaving between January and May means lump-sum collection," but the lump sum is mandatory only when your date of departure falls between January 1 and April 30. If you leave in May, the May installment is the last one, so there is no balance left over.
If you already have a new employer, the balance can also be carried over and kept under special collection at the new workplace. The deadline for applying and the month the deduction restarts are explained in When residence tax deduction starts after changing jobs.
Because residence tax is paid later, even in a year when your income has dropped after leaving a job, you are charged residence tax on the previous year's income (the year you were working). A sizable payment slip arrives during a period of unemployment or reduced income, so it's reassuring to set the money aside separately from your living expenses.
Tax on a retirement allowance
A retirement allowance (lump-sum retirement payment) is treated as retirement income and is calculated separately from salary under a preferential method. The longer you have worked, the larger the deduction you can receive.
Retirement income deduction: 20 years of service or less = ¥400,000 × years of service (minimum ¥800,000) / more than 20 years of service = ¥8,000,000 + ¥700,000 × (years of service − 20). Any fraction of a year of service is rounded up.
If you submit this report to your employer, withholding is completed with the preferential calculation above, and in principle no tax return is needed. If you forget to submit it, a flat 20.42% is withheld on the retirement allowance amount, and you recover the overpayment through a tax return[National Tax Agency No.2732].
When you receive iDeCo as a lump sum, you use the retirement income deduction; but if you then receive your employer's retirement allowance, the adjustment period that prevents duplicating the deduction was extended from 5 to 10 years starting January 2026. Because the tax amount changes with the order and timing of receipt, consider the timing of receiving iDeCo and your retirement allowance early.
Switching social insurance and pension (for those with a gap period)
If you don't move straight into a new job after leaving, you switch your health insurance and pension yourself.
・Health insurance: one of ① voluntary continuation (up to 2 years) ② National Health Insurance ③ becoming a dependent of a family member
・Pension: from employees' pension to the National Pension (Category 1). Complete the procedure at your municipality within 14 days of the day after your departure date
These premiums are eligible for the social insurance premium deduction, so don't forget to claim them on your tax return.
FAQ
Do I need to file a tax return if I didn't change jobs by the end of the year?
Because you can't receive a year-end adjustment, you file a tax return the following year. Since over-withholding often results in a refund, it's worth filing even though it's a hassle.
Do I need to file a tax return for a retirement allowance too?
In principle it's not needed if you submitted the "Report on receipt of retirement income" to your employer. If you didn't submit it, a flat 20.42% is withheld, so you settle it and recover the amount through a tax return.
Why did a residence tax bill arrive the year after I left my job?
Because residence tax is paid later on the previous year's income. Even if your income dropped after leaving, residence tax on the previous year (when you were working) is still charged. You pay it with ordinary-collection payment slips.
What if I lost the withholding tax statement from my previous job?
Ask your previous company to reissue it. The withholding tax statement is essential for the year-end adjustment at your new job or for a tax return, so be sure to obtain it.
Summary
Reference links (sources)
This article is based on materials from the following public bodies (neutral, primary sources). Because the rules are amended, please check the latest content before doing any procedure.
- National Tax Agency No.1420 When you receive a retirement allowance (retirement income) (in Japanese)
- National Tax Agency No.2732 Withholding on retirement allowances, etc. (in Japanese)
- National Tax Agency No.1910 When you left partway through and did not receive a year-end adjustment (in Japanese)
- Ministry of Internal Affairs and Communications — Individual residence tax (in Japanese)
* This article is general information, not tax advice. For individual decisions, please confirm with a tax office or a tax accountant.
