"Retirement Allowance Navi" Releases "Net Income Reverse Calculation Simulator" for Retirement Allowances ── AI Calculates Necessary Gross Retirement Allowance and Optimal Receipt Method from "I Want XX Million Yen in Net Income"

The retirement allowance information service "Retirement Allowance Navi" (https://taisyoku.xyz) has released a "Net Income Reverse Calculation Simulator" that calculates the gross amount of retirement allowance required and the optimal receipt method based on the desired net income. Tool URL: https://taisyoku.xyz/tools/reverse-calculator

Are you relieved to hear "20 million yen gross"?

Almost all figures mentioned in discussions about retirement allowances are "gross" amounts. The amount written in company regulations, the amount heard from colleagues, the average amount seen online—none of these are net income. Retirement allowances are subject to income tax and resident tax. Furthermore, the tax calculation method differs completely depending on whether the receipt method is a "lump sum" or an "annuity." There is a significant difference in net income for the same gross amount between a lump sum, which can utilize the retirement income deduction, and an annuity, which is taxed annually as miscellaneous income. According to statistics from the National Tax Agency, the number of retirement income declarants in 2022 was approximately 770,000 (Source: National Tax Agency "Statistical Annual Report" 2022). Many people receiving retirement allowances face tax calculations, but only a small fraction simulate in advance "which is better, a lump sum or an annuity." According to the Ministry of Health, Labour and Welfare's "General Survey on Working Conditions" (2023), among companies with a retirement benefit system, "retirement lump-sum payment system only" accounts for 69.0%, "retirement annuity system only" for 9.6%, and "both systems combined" for 21.4% (Source: Ministry of Health, Labour and Welfare "Reiwa 5th General Survey on Working Conditions"). Those working for companies with combined systems may be able to choose the ratio of lump sum to annuity themselves, and the final net income will change depending on that ratio.

The Decisive Difference from Conventional Simulators

Conventional retirement allowance simulators followed the flow of "input gross amount → calculate net income." However, what people actually considering retirement want to know is the reverse. "I want to secure 15 million yen net for my retirement funds," "I need 8 million yen net to repay the remaining 8 million yen of my housing loan in one go," "My budget for what I want to do after retirement is based on net income." This tool reverses the input and output to meet these needs of "I want XX million yen in net income."

How the Simulator Works

Step 1: Enter Desired Net Income
First, enter "how much net income you want." The amount can be freely set in units of 10,000 yen.

Step 2: Enter Basic Information
- Years of service
- Reason for retirement (personal reasons / company reasons / mandatory retirement)
- Planned retirement age
- If there is a retirement annuity, the annuity receipt period and interest rate
- Estimated other income (re-employment plans, real estate income, etc.)
Since the retirement income deduction amount differs depending on the reason for retirement (for years of service exceeding 20 years, it's 700,000 yen x number of years), these items are essential for accurate calculations.

Step 3: AI Calculates 3 Patterns in Reverse
Based on the entered conditions, AI calculates the "gross amount required to achieve the desired net income" for the following three receipt patterns:

1. Full Lump Sum Pattern
This utilizes the retirement income deduction to its fullest and calculates taxes under separate taxation. This method is advantageous for long-term employees, as the deduction amount increases with longer years of service. The necessary gross amount, deduction amount, and breakdown of income tax and resident tax are displayed.

2. Full Annuity Pattern
This calculates the case where the amount is received annually as an annuity. Since it is subject to comprehensive taxation as miscellaneous income, the tax rate may increase when combined with other income. The total annuity receipt amount (gross) and a list of net income changes for each year during the receipt period are displayed.

3. Lump Sum + Annuity Combined Pattern
AI calculates the optimal ratio of lump sum to annuity. It is common to allocate the amount that fully utilizes the retirement income deduction as a lump sum and receive the remainder as an annuity, but the optimal solution changes depending on other income situations.

Step 4: Output Comparison Table
A comparison of the three patterns can be viewed on one screen. The four comparison items are "Total Gross Amount Required," "Total Taxes and Social Insurance Premiums," "Effective Net Income Rate (Net Income ÷ Gross Amount)," and "Period Until Receipt Completion."

When to Use This Tool

1. For financial planning for those retiring in 3-5 years
By calculating "how much net income is needed" at an early stage, you can plan to supplement any shortfall with iDeCo, NISA, etc. The value of this tool lies in being able to prepare several years in advance, rather than rushing to calculate just before retirement.

2. For those considering a lump-sum repayment of their remaining housing loan balance
If you are thinking of "paying off your loan with your retirement allowance," the necessary net income amount is the same as the remaining loan balance. By entering that amount, you can immediately know how much gross amount is needed to pay it off. If the gross amount falls below the company's retirement allowance regulations, you can also plan to supplement part of it with your own funds.

3. As a decision-making tool for those considering a job change
You can compare how your net income changes if you retire with your current years of service versus if you retire after working a few more years. Since the retirement income deduction increases by 700,000 yen per year for years of service exceeding 20 years, a difference of a few years can significantly impact net income for those around the 20-year mark.

Also Supports the Impact of the 2025 Tax Reform

Discussions are ongoing regarding a review of the differences in deduction amounts based on years of service concerning retirement income taxation (Outline of the 2025 Tax Reform, Liberal Democratic Party and Komeito, announced December 2024). The simulator calculates based on the current tax system, but the logic will be promptly updated if revisions are implemented.
* This simulation is an estimate. Actual tax amounts may vary depending on individual circumstances. Please consult a tax professional for accurate tax calculations.

▼ Net Income Reverse Calculation Simulator is here
https://taisyoku.xyz/tools/reverse-calculator

■ Company Overview
Company Name: Mycat Inc.
Established: February 5, 2025
Location: 2-7-22 Mita, Meguro-ku, Tokyo
Business Activities: Planning, development, and operation of AI-powered services for SMEs and individuals
Latest News: https://taisyoku.xyz/news
Corporate Site: https://mycat.business
Contact: info@mycat.business

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