Post-Retirement Tax Calendar

4.10

Derivation Chain

Step 1 Changes in industry employment + surge in retirements

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Step 2 Confusion over tax and social insurance filing deadlines immediately after retirement

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Step 3 Organizing monthly tax and insurance filings into a calendar

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Step 4 Simulation of additional taxes for missed filings

Problem

Retirees aged 55-60 must handle at least 8-10 tax and social insurance filings in the first year after retirement (retirement income tax settlement, comprehensive income tax filing, health insurance local subscriber conversion, national pension voluntary continued enrollment application, resident tax, property tax, etc.), but there is no service that provides this schedule in one place. Since these were handled by the company's accounting team while employed, it's the first time doing it themselves, and missing deadlines results in additional taxes (up to 20%). They must check the National Tax Service's HomeTax, Health Insurance Corporation, and National Pension Service websites separately, and there is no comprehensive guidance on what to do by when.

Solution

By entering 5 basic pieces of information on the web (retirement date, retirement payment method (lump sum/annuity), real estate ownership, other income presence, etc.), it automatically generates a monthly calendar of 'what to do this month' for the 12 months after retirement. For each item, it shows the filing deadline, filing method (HomeTax/visit/phone), required documents, and estimated additional tax if overdue. It provides notifications 7 days before deadlines.

Target: Aged 55-62, immediately after regular or honorary retirement (within 6 months of retirement), former office/management workers with 30+ years of employment and little to no experience with tax filing.

Revenue Model: Free: basic calendar + 5 major items. Premium (9,900 KRW per transaction, approx. $7.43): all items + additional tax simulation + customized document checklist PDF + deadline notifications. Future possibility of tax accountant consultation referral fee (5,000 KRW per transaction, approx. $3.75).

Ecosystem Role: Regulation

MVP Estimate: 2_weeks

NUMR-V Scores

N Novelty

4.0/5

U Urgency

4.0/5

M Market

3.0/5

R Realizability

5.0/5

V Validation

3.0/5

NUMR-V Scoring System

N Novelty	1-5	How uncommon the service is in market context.
U Urgency	1-5	How urgently users need this problem solved now.
M Market	1-5	Market size and growth potential from proxy indicators.
R Realizability	1-5	Buildability for a small team with realistic constraints.
V Validation	1-5	Validation signal quality from competition and demand data.

N=.15 U=.20 M=.15 R=.30 V=.20

Feasibility (77%)

Tech Complexity

34.7/40

Data Availability

22.5/25

MVP Timeline

20.0/20

API Bonus

0.0/15

Feasibility Breakdown

Tech Complexity	/ 40	Difficulty of core implementation stack.
Data Availability	/ 25	Practical availability and cost of required data.
MVP Timeline	/ 20	Expected time to ship a usable MVP.
API Bonus	/ 15	Bonus for viable public API leverage.

Market Validation (59/100)

Competition

8.0/20

Market Demand

6.2/20

Timing

14.0/20

Revenue Signals

10.5/15

Pick-Axe Fit

12.0/15

Solo Buildability

8.0/10

Validation Breakdown

Competition	/ 20	Signal quality from competitor landscape.
Market Demand	/ 20	Demand proxies from search and mention patterns.
Timing	/ 20	Fit with current shifts in tech, behavior, and regulation.
Revenue Signals	/ 15	Reference evidence for monetization viability.
Pick-Axe Fit	/ 15	How well the concept serves participants in a trend.
Solo Buildability	/ 10	Practicality for lean-team implementation.

Technical Requirements

Frontend [low] Backend [medium] Data Pipeline [low]

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