About Okane Keisan

Okane Keisan (お金計算 in Japanese) offers free calculators for money in Japan: take-home pay, bonuses, retirement pay, income tax, resident tax and mortgages. Every calculation runs in your browser. The numbers you enter are not sent to our servers or anywhere else, and they are not stored.

This English edition currently covers the take-home pay, bonus and retirement pay calculators. Additional calculators and most guides are available in the Japanese edition (日本語).

How we keep the numbers accurate

Tax rates, deductions and social insurance rates are checked directly against primary sources: the National Tax Agency, the Japan Pension Service, the Japan Health Insurance Association (協会けんぽ) and the Ministry of Internal Affairs and Communications. Each calculator page lists its sources. Most of them are published only in Japanese; we label them as such.

Where a calculation is simplified (for example, using the national average health insurance rate rather than your prefecture's rate) the calculator page says so. The English and Japanese editions use the same calculation code, so they always give the same numbers.

Who the calculators are for

The salary calculators assume a salaried employee who is a resident of Japan and is covered by the employees' pension and the Japan Health Insurance Association health plan. Non-residents, the self-employed and other special cases are taxed differently and are not covered by the salary tools. The pension-withdrawal calculator is specifically for eligible foreign nationals leaving Japan; check each tool’s stated scope.

Not professional advice

The results are estimates, not tax, legal, or financial advice. For your own situation, ask a tax accountant (zeirishi), a labour and social security attorney (shakai hoken roumushi) or your employer's payroll department.

Who runs this site

Okane Keisan is run and maintained by one person. If you find an error in a calculation, please check the sources listed on the calculator page and then contact us.

Verification and corrections

The independent operator maintains the calculations and explanations using public sources. This is not a tax practice, and we do not claim that every page has been reviewed by a licensed tax professional.

Calculation changes are checked against official worked examples or independent hand calculations, with automated tests for boundaries. Before publication we check links, headings, sources, caveats and language-pair consistency. Tests do not certify a calculation for your individual tax circumstances. Both editions share calculation code, and changes to rules or caveats are reflected in both languages.

To report a possible error, use the contact page and include the page URL, the disputed result or passage, and an official source if available. Use fictional example numbers; do not send account numbers, identity documents or tax returns. Verified errors are corrected in the calculation or text and its related explanations.