Mio doesn't guess — she does the arithmetic on the Japanese-language official tables. Enter your average monthly salary (a stand-in for your "standard remuneration") and how many months you paid Employees' Pension, and Mio estimates your gross lump-sum, the 20.42% tax taken at source, and what you'd actually keep — with and without reclaiming the tax. It is a rough estimate, not your exact refund. The real figure depends on your recorded standard-remuneration history and the current official schedule.
This tool models the Employees' Pension (厚生年金 / Kosei Nenkin) lump-sum, which is salary-based. The National Pension (国民年金 / Kokumin Nenkin) lump-sum uses a different fixed-amount table by months instead — it exists, but it isn't what's calculated here.
| What you actually keep (estimate) | Amount |
|---|
Leaving Japan is a moving target of deadlines — pension, tax, resident tax, closing accounts. The pension refund alone can be worth close to a million yen, and the 20.42% reclaim on top is real money that quietly expires. Get the sequence right before your final departure, because most of it can't be fixed after you've gone.
For the Employees' Pension, the official framework is roughly: gross lump-sum ≈ your average standard remuneration × a "payment rate" that grows with the number of contribution months, in 6-month bands, up to a cap. Mio uses this illustrative band table (the "final month April 2021 or later" schedule):
| Months paid | Illustrative multiplier (× average monthly salary) |
|---|---|
| 6 – 11 | 0.5 |
| 12 – 17 | 1.1 |
| 18 – 23 | 1.6 |
| 24 – 29 | 2.2 |
| 30 – 35 | 2.7 |
| 36 – 41 | 3.3 |
| 42 – 47 | 3.8 |
| 48 – 53 | 4.4 |
| 54 – 59 | 4.9 |
| 60+ (current CAP) | 5.5 |
These multipliers match the current 日本年金機構 (Japan Pension Service) "final month April 2021 or later" table (the 36–41 month band uses 3.3, topping out at 5.5 at 60 months). The count used is currently capped at 60 months (5 years) per the current JPS page. Future pension-reform changes to the cap may follow, so verify the current table before relying on any number. Under 6 months of contributions usually means no lump-sum at all. Then income tax of 20.42% (including the reconstruction surtax) is withheld from the gross at source.
Here's the part people miss. The lump-sum is taxed as retirement income (退職所得), and this estimator now does the real retirement-income calculation rather than assuming a flat percentage:
For short stints the deduction often exceeds the gross lump-sum, so the actual tax due is ¥0 and the entire 20.42% is refundable. For larger lump-sums some tax is genuinely owed, and only the difference comes back. To get it you must appoint a tax representative (納税管理人 / nozei kanrinin) in Japan before you leave, then file a Japanese tax return after you've received the lump-sum. The representative files, receives the refund, and remits it to you — but only if you set it up in time. This tool uses your entered months to estimate years of service; if it can't work out a proper figure it says so rather than inventing a number.
Mio