Detailed Tax & Social Insurance Simulation (Free, No Registration)
This is an advanced tool that gives a detailed estimate of your take-home pay, taxes, and social insurance premiums by entering your family structure and deductions. It reflects the post-2025 (Reiwa 7) reform: basic deduction (¥580,000–¥950,000) and employment income deduction (minimum ¥650,000). The figures you enter are not sent anywhere and are calculated only on your own device. If you just want a rough estimate, try the simplified calculators.
① Employee Take-Home Pay — Detailed Simulation
Calculates take-home pay after deducting social insurance premiums (health insurance, employees' pension, employment insurance), income tax, and residence tax from your annual income (gross, including bonuses). Reflects the spousal deduction, dependent deduction, iDeCo, and life insurance premium deduction. Health insurance uses the national average level of Kyokai Kenpo (10.0% split evenly between employer and employee; long-term care 1.6%), and the estimate also accounts for the standard remuneration caps (e.g., ¥650,000/month for the employees' pension).
② Sole Proprietor Taxes & Premiums — All-in-One Simulation
Estimates all five together — income tax, residence tax, National Health Insurance, National Pension, and enterprise tax — from your revenue and expenses. It correctly reflects fine distinctions such as the blue-return special deduction "applying to National Health Insurance but not to enterprise tax." The National Health Insurance rate defaults to the level of Tokyo's 23 wards, and you can change it to your own municipality's rate.
③ Inheritance Tax — Detailed Simulation (with Spousal Tax Credit)
From the net estate value (assets minus debts and funeral expenses) and family structure, this calculates the "total tax the whole family owes," reflecting the basic exclusion, the statutory-share taxation method, and the spousal tax credit (tax-free up to ¥160 million or the statutory share). It is an estimate that does not include the small-scale residential land special exception, the life-insurance non-taxable allowance, or the like.
Also worth reading: How to read your withholding tax slip / How National Health Insurance premiums are calculated / Enterprise tax / Inheritance tax basic exclusion & tax-saving strategies
[Disclaimer & assumptions] This tool provides estimates based on the system as of June 2026 (Reiwa 7 income tax: basic deduction ¥580,000–¥950,000 〈including the Reiwa 7 & 8 add-on〉, employment income deduction minimum ¥650,000; FY Reiwa 7: National Pension ¥17,510/month, residence tax 10% + per-capita levy etc. ¥5,000). Health insurance rates, National Health Insurance rates, and per-capita levies vary by insurer and municipality. Because residence tax is levied the following fiscal year, it is shown here as the annual tax corresponding to your income. Social insurance premiums on bonuses are approximated on a monthly-proration basis, and adjustments such as the residence-tax adjustment credit are simplified. Actual taxes and premiums vary with circumstances, so confirm exact amounts with the tax office, your municipality, a tax accountant, etc. Input values are processed only on your device and are not sent to any server.