If you leave Japan after a few years of work, part of what you paid into the pension comes back as a lump sum, the dattai ichijikin (脱退一時金). In Vietnamese and Indonesian, Google suggests questions like "how much after 3 years" and "how long until it comes" for it, and I found no calculator in either language. So I built one, in the seven languages of the Hub.
What comes back
The pension refund calculator asks for your months in employees' pension, your average pay and bonuses, any months of national pension you paid yourself, and the month you leave. 36 months on 250,000 yen a month give a lump sum of 858,000 yen. The pension service withholds 20.42 % income tax, 175,203 yen, so 682,797 yen reaches your bank.
Getting the tax back
The 175,203 yen comes back through a return for selective taxation, which a tax representative in Japan files for you. It taxes the lump sum as retirement income instead, and three years give a deduction of 1.2 million yen, more than the lump sum, so all of it comes back. The page works this out for your own figures and gives the dates: two years to claim, the money about four months after the claim arrives, and the tax return from the January after.
The cap is still five years
A 2025 law raises the cap from 5 to 8 years, from a date a cabinet order will set. The Japan Pension Service's page, updated on 1 April 2026, still counts at most 60 months, while some websites already promise 96. The calculator counts 60. Below it, the page lists every step from the moving-out notice to the tax return, each taken from the pension service's or the tax agency's own pages.
