Money
Bonus Take-Home Pay Calculator | Social Insurance & Withholding Tax
Estimate your bonus take-home pay from the gross bonus amount and last month's salary, including health, pension, and employment insurance plus withholding tax. Supports number of dependents.
| Gross Bonus Amount |
JPY
|
|---|---|
| Last Month's Salary |
JPY
Enter the amount after social insurance deductions (used to determine the withholding tax rate).
|
| Prefecture | |
| Long-Term Care Insurance |
|
| Number of Dependents |
people
|
| Dependent Deduction Form |
Turn this on if you have NOT submitted the dependent deduction form (higher "Column B" tax rate applies). Usually leave this off.
|
Estimated Result
| Gross Bonus Amount | [[ fmt(result.bonusAmount) ]] JPY |
|---|---|
| Standard Bonus Amount | [[ fmt(result.standardBonus) ]] JPY |
| Health Insurance | - [[ fmt(result.healthIns) ]] JPY |
| Care Insurance | - [[ fmt(result.careIns) ]] JPY |
| Pension Insurance | - [[ fmt(result.pensionIns) ]] JPY |
| Employment Insurance | - [[ fmt(result.employmentIns) ]] JPY |
| Total Social Insurance | - [[ fmt(result.socialInsTotal) ]] JPY |
| Withholding Tax Rate | [[ result.taxRate.toFixed(3) ]] % |
| Withholding Tax (incl. reconstruction tax) | - [[ fmt(result.withholdingTax) ]] JPY |
| Take-Home Bonus | [[ fmt(result.netBonus) ]] JPY |
This calculation is based on the following assumptions and may differ from your actual take-home amount.
- Health insurance assumes enrollment in <strong>Kyokai Kenpo</strong> (Japan Health Insurance Association). Union-run health insurance societies use different rates.
- The standard bonus amount is capped at ¥5.73 million per fiscal year for health insurance and ¥1.5 million per payment for pension insurance, but this tool applies both caps <strong>per single payment as a simplification</strong>. Results will differ if you receive multiple bonuses in the same fiscal year.
- Withholding tax is calculated using the National Tax Agency's official bonus withholding rate table, but <strong>if you had no salary last month or your bonus exceeds 10 times last month's salary</strong>, a different monthly-table calculation applies instead, which this tool does not replicate.
- The employment insurance rate used is the employee's share (0.6%) for <strong>general businesses</strong>. Agriculture/forestry/fisheries, sake brewing, and construction industries use different rates.
Tips
- Enter last month's salary after social insurance deductions — this is your gross pay minus health/pension/employment insurance, not your final take-home pay.
- Bonus insurance premiums use the same rate table as your monthly salary, so the amount varies by prefecture. If you are relocating soon, try comparing rates for your new prefecture too.
- If you receive a bonus from a side job where you have not submitted a dependent deduction form, turn on the "Dependent Deduction Form" switch to apply the higher Column B rate.
- For companies paying bonuses twice a year (summer and winter), calculate each payment separately to get a clearer picture of your total annual take-home pay.
Frequently Asked Questions
Side Note — Why Japanese Bonuses Are Legally a "Discretionary Payment"
Unlike a contractual incentive payment common in many Western countries, a Japanese bonus (shoyo) is legally classified as a discretionary, goodwill payment defined by a company's work rules or labor agreement rather than by statute. This means it can legally be reduced or withheld entirely in a bad business year. The custom is said to trace back to the Edo-period practice of "shikise," where merchant house owners gave money or goods to their employees, later formalized into a recurring twice-yearly payment by companies in the Meiji era.
The "standard bonus amount" used to calculate social insurance is deliberately kept as a separate framework from the "standard monthly compensation" used for salaries. This lets insurers apply the same premium rates to both while still capping the total premium collected on very large bonuses — ¥5.73 million per fiscal year for health insurance and ¥1.5 million per payment for pension insurance. Because amounts above these caps are exempt from further premiums, executives receiving very large bonuses can end up with a lower effective insurance burden than an average employee, a mild regressive effect some critics have pointed out.
The reason the withholding tax calculation depends on "last month's salary" is that a bonus is treated as windfall income layered on top of a person's normal standard of living, so the tax table approximates a progressive rate based on their typical monthly income level. This means someone who happened to work unusually heavy overtime the month before receiving their bonus may end up with a withholding rate that does not reflect their real annual income — one of the reasons year-end tax adjustments exist to true up any over- or under-withholding.