B

Rental Income Tax Auto-Calculator

3.50

Derivation Chain

Step 1 PolicyPlus Tax and Real Estate policies
→
Step 2 Increase in Rental income earners in their 50s
→
Step 3 Complexity of Tax structure on Rental income

Problem

Small-scale landlords in their 50s-60s (owning 1-3 studio apartments or officetels) cannot independently calculate whether separate taxation or comprehensive taxation is more advantageous for their annual Rental income, what the deemed expense rate is, or how much additional national health insurance premiums will be assessed. Even when choosing separate taxation for Rental income under 20 million KRW (~$15,000), taxes vary significantly depending on registered Rental status and deemed expense rates (50% vs. 42.6%), but almost no landlords understand this structure. Errors are frequent when self-filing on HomeTax (Korea's online Tax filing system).

Solution

Enter number of Rental properties, monthly rent, deposits, and registered Rental status to automatically calculate separate vs. comprehensive taxation comparison, actual Tax payable after applying deemed expense rates, and additional national health insurance premium assessments. Includes scenario comparisons like 'How much would you save by converting to registered Rental?'

Target: Ages 50-65, owning 1-5 small Rental properties, annual Rental income of 10-40 million KRW (~$7,500-$30,000), whose scale is too small to justify hiring a Tax accountant
Revenue Model: Basic calculation free. Annual Rental income comprehensive Report (for Tax filing) PDF at 5,000 KRW (~$3.75). Tax accountant filing service referral.
Ecosystem Role: Consumer
MVP Estimate: 2_weeks

NUMR-V Scores

N Novelty
2.0/5
U Urgency
4.0/5
M Market
4.0/5
R Realizability
4.0/5
V Validation
4.0/5
NUMR-V Scoring System
N Novelty1-5How uncommon the service is in market context.
U Urgency1-5How urgently users need this problem solved now.
M Market1-5Market size and growth potential from proxy indicators.
R Realizability1-5Buildability for a small team with realistic constraints.
V Validation1-5Validation signal quality from competition and demand data.
Each dimension is scored 1-5 and weighted into grade S/A/B/C/D.
SaaS N=.15 U=.20 M=.15 R=.30 V=.20 Senior N=.25 U=.25 M=.05 R=.30 V=.15

Feasibility (75%)

Tech Complexity
32.0/40
Data Availability
23.1/25
MVP Timeline
20.0/20
API Bonus
0.0/15
Feasibility Breakdown
Tech Complexity/ 40Difficulty of core implementation stack.
Data Availability/ 25Practical availability and cost of required data.
MVP Timeline/ 20Expected time to ship a usable MVP.
API Bonus/ 15Bonus for viable public API leverage.
Total 100 points; below 50% is filtered out.

Market Validation (60/100)

Competition
8.0/20
Market Demand
6.2/20
Timing
16.0/20
Revenue Signals
10.5/15
Pick-Axe Fit
12.0/15
Solo Buildability
7.0/10
Validation Breakdown
Competition/ 20Signal quality from competitor landscape.
Market Demand/ 20Demand proxies from search and mention patterns.
Timing/ 20Fit with current shifts in tech, behavior, and regulation.
Revenue Signals/ 15Reference evidence for monetization viability.
Pick-Axe Fit/ 15How well the concept serves participants in a trend.
Solo Buildability/ 10Practicality for lean-team implementation.
Total 100 points; below 50 is filtered out.

Technical Requirements

Frontend [low] Backend [medium]
Dashboard