- What comes out of a bonus
- The standard bonus amount and five-day report
- How the bonus tax rate table works
- Three common bonus mistakes
The short answer
Health insurance and the child and child-rearing support levy (and long-term care where applicable), pension, employment insurance and income tax all come out of a bonus — but on a different basis from monthly pay. Social insurance uses the *standard bonus amount*; income tax uses the bonus withholding rate table. Never reuse the monthly formula.
Social insurance
The Japan Pension Service treats as bonuses payments made three times a year or less; four or more times a year counts as monthly remuneration. The standard bonus amount is the pre-tax bonus with anything under 1,000 yen dropped, capped for pension at 1.5 million yen per payment (health insurance has its own cap). A bonus payment report must reach the Japan Pension Service within five days of the payment date — a commonly missed step.
Employment insurance and income tax
Employment insurance is the actual amount paid times the rate, with no standard-amount conversion; the rate can change each fiscal year. Income tax uses the bonus rate table, not the monthly table: the rate comes from the previous month's pay after social insurance and the number of dependants, and applies to the bonus after social insurance. Bonuses paid from 1 January 2026 use the 2026 table.
Three common mistakes
- Reusing the monthly pay formula for the bonus
- Copying the previous bonus's settings and missing changes since
- Not applying updated rates or tables
Keep bonuses as a separate calculation
Hold monthly pay and bonuses as separate calculations with their own tables, and keep a yearly view of both — it helps at year-end adjustment and when checking the three-times-a-year rule.
Summary
Bonuses use the standard bonus amount and the bonus rate table, and need a report within five days. Check rates and tables every time.