Multi-Job Portfolio Calculator

Multi-Job Portfolio Calculator helps compare job, salary, or work-life choices with editable employment assumptions.

Multi-job portfolio inputs

Calls the Korean N-job portfolio module with side-income withholding, expense rates, HHI concentration, weekly hour warnings, and health-insurance threshold checks.

Total monthly net income

₩5,507,600

Gross income ₩6,300,000

Side income share

44.4%

HHI 0.388

Average hourly net

₩20,705

Main hourly ₩19,886

Weekly hours

61.2

danger workload level

Estimated annual tax

₩4,649,238

Additional payment ₩3,540,438

Health insurance warning

Yes

Side business income ₩33,600,000

Side job detail

Freelance project

₩1,400,500

A efficiency; withholding ₩49,500

Delivery work

₩623,600

A efficiency; withholding ₩26,400

Creator income

₩403,500

A efficiency; withholding ₩16,500

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Korea multi-job portfolio calculator guide

This English page translates the Korean N-job portfolio calculator and calls calculatePortfolio. It keeps side-income types, withholding, expense assumptions, overwork warnings, HHI concentration, tax estimates, and health-insurance warning logic.

Income types and withholding

The Korean content distinguishes side job types instead of treating every side income alike. Freelance and creator income use 3.3% withholding, delivery income uses 3.3% withholding with a 75.3% expense assumption, online sales have no withholding in the simplified model, lectures and manuscripts use 8.8% withholding with 60% expenses, financial income uses 15.4%, and rental income can have separate treatment below KRW 20,000,000.

The calculator calculates monthly gross income, monthly expenses, withholding, monthly net income, hourly gross rate, hourly net rate, efficiency grade, and contribution percent for each side job.

Tax and health insurance

Comprehensive income tax uses the 2026 progressive structure from 6% to 45% plus local income tax at 10% of income tax. The module estimates taxable income differently for employees, self-employed workers, financial income, lecture income, and business-style side income.

For employees, side business income above KRW 20,000,000 can trigger additional health insurance. The Korean constants keep Health Insurance at 7.19% and long-term care at 13.14% of health insurance for the warning analysis.

Time, efficiency, and concentration

The time summary preserves weekly workload warnings: 52 hours is a warning level and 60 hours is a danger level. It converts monthly hours to weekly hours using 4.345 weeks per month, then reports daily work hours and estimated leisure time.

The portfolio diagnosis also uses the Herfindahl-Hirschman style concentration index. A value above 0.5 signals high concentration, while a diversified portfolio is closer to 0.3 or below. Efficiency grades compare side-job hourly net income with the main job hourly rate: A at 80% or above, B at 50% or above, and C below that.

Planning rules

The Korean article advises setting aside roughly 10% to 15% of side income for tax and maintaining evidence for expenses, platform income, invoices, card statements, and deposits. A high monthly net number can still create a tax payment later if withholding is too low.

The Korean page also caps the practical side-job count at 5 in its constants. Too many low-efficiency income streams can reduce net hourly value, increase burnout risk, and make tax records harder to manage.