Japan Bonus Take-Home Pay Simulator (Free) | Social Insurance & Withholding Tax
Simulate your Japan bonus take-home pay for free — enter the gross bonus and last month's salary to calculate insurance and withholding tax instantly, by prefecture and 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 |
| Child and Childcare Support Levy | - [[ fmt(result.childcareLevy) ]] 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 (0.5%) for <strong>general businesses</strong>. Agriculture/forestry/fisheries, sake brewing, and construction industries use different rates.
What Is a Japan Bonus Take-Home Pay Calculation?
A Japan bonus (shoyo) take-home pay calculation estimates how much of your gross bonus actually lands in your bank account after health insurance, pension insurance, employment insurance, and withholding tax are deducted. Because Japan's payroll system applies prefecture-specific insurance rates and treats bonus withholding tax differently from regular monthly salary, the final amount is rarely as simple as multiplying the gross figure by a flat percentage.
Bonus-related social insurance premiums use the same rate tables as your regular monthly salary, but the withholding tax is calculated from a separate National Tax Agency table that keys off your salary from the month immediately before the bonus payment. This tool reproduces both calculations so you can see, step by step, how a gross bonus figure turns into a net amount before payday.
Sources used in this calculation
Statutory figures such as tax and insurance rates come from the public bodies listed below. They change when the law is revised, so please also check the primary source before relying on the result for an important decision.
- Health insurance rate — Japan Health Insurance Association (全国健康保険協会・協会けんぽ) Effective 2026-03 to 2027-02 ／ Last checked 2026-09-03
- Long-term care insurance rate — Japan Health Insurance Association (全国健康保険協会・協会けんぽ) Effective 2026-03 to 2027-02 ／ Last checked 2026-09-03
- Child and childcare support levy — Japan Health Insurance Association (全国健康保険協会・協会けんぽ) Effective 2026-04 to 2027-03 ／ Last checked 2026-09-03
- Employees' pension insurance rate — Japan Pension Service (日本年金機構) Effective from 2017-09 ／ Last checked 2026-09-03
- Employment insurance rate — Ministry of Health, Labour and Welfare (厚生労働省) Effective 2026-04 to 2027-03 ／ Last checked 2026-09-03
- Income tax rates — National Tax Agency (国税庁) Effective from 2015-01 ／ Last checked 2026-09-03
- Basic deduction and employment income deduction — National Tax Agency (国税庁) Effective from 2025-01 ／ Last checked 2026-09-05
How to Use This Calculator
- Enter your gross bonus amount Input the total bonus figure your employer notified you of, before any deductions.
- Enter last month's salary Use the amount after social insurance deductions — this determines which withholding tax rate applies.
- Select your prefecture and care insurance status Health insurance rates vary by prefecture, and employees aged 40–64 also pay long-term care insurance.
- Enter your number of dependents The withholding tax rate changes depending on how many dependents you have declared.
- Review the estimated result The calculator displays the social insurance breakdown, withholding tax, and final take-home bonus.
Tips for getting more out of it
- 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.
When to Use This Calculator
Planning around a bonus notice
Once your employer announces the bonus amount, estimate the actual deposit ahead of time to plan large purchases or savings.
Comparing take-home pay before and after a transfer
Health insurance rates differ by prefecture, so you can compare how a relocation would change your bonus take-home amount.
Estimating a side-job bonus
If you receive a bonus from a workplace where you have not filed a dependent deduction form, estimate the take-home amount under the higher Column B rate.
Adding up annual bonus income
Calculate summer and winter bonuses separately, then add the results together to estimate your total annual take-home bonus income.
Glossary
- Standard Bonus Amount (hyojun shoyo-gaku)
- Your gross bonus rounded down to the nearest 1,000 yen. Social insurance premiums are calculated by multiplying this figure by the applicable rate, subject to caps (¥5.73 million per fiscal year for health insurance, ¥1.5 million per payment for pension insurance).
- Withholding Tax (gensen choshu zei)
- Income tax, including the special reconstruction surtax, deducted directly from the bonus. The rate is looked up from the National Tax Agency's official bonus withholding table using last month's salary and number of dependents.
- Dependent Deduction Form (fuyo kojo tou shinkokusho)
- A form filed with your main employer. If filed, the lower "Column A" rate applies; if not filed — typically at a secondary or side job — the higher "Column B" rate applies instead.
- Kyokai Kenpo
- The Japan Health Insurance Association, which covers employees at small and medium-sized companies. Its health insurance premium rate varies by prefecture.
- Year-End Adjustment (nenmatsu chosei)
- A year-end recalculation of the total withholding tax owed on your salary and bonus income for the year, which settles any over- or under-collection. Because bonus withholding is only an estimate, differences often surface here.
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.