Calculation Guides
Worked examples explain how the numbers are calculated and when they matter. Each guide identifies its applicable year, assumptions and sources. Check current official guidance before filing or signing a contract.
Gross vs. Net Salary in Korea: Why the Gap? (2026 Guide)
Explains 2026 Korean insurance, withholding, and non-taxable pay, then reproduces a KRW 36M-to-48M salary increase and the monthly take-home difference with the A/B calculator.
Korean Severance Pay 2026: Calculation and Retirement Tax Explained
An overview of ordinary average-wage severance, 2026 retirement-income deductions, IRP tax deferral, and exceptions that require separate review.
When Does Refinancing a Loan Pay Off? A Break-Even Framework
Compare quoted refinancing fees paid upfront or financed, and check an example where a longer term increases total interest despite lower payments, plus break-even estimate limits.
5 Reasons BMI Alone Misleads — and What to Measure Alongside
Why BMI misclassifies muscular, elderly, or abdominally obese individuals — and which complementary metrics to use.
Korean VAT Filing for Self-Employed: 2026 Practical Guide
Simplified vs. general VAT, deductible purchases, a pre-filing checklist, and a worked example.
Korea's Unified Age Act: What Changed, What Didn't
Post-2023 age-system changes, and the military/alcohol/school contexts that still use year-age.
Why "30% + 20% Off" Isn't 50% — Discount Stacking Math
Stacked-discount formula, five common traps, and a 3-second mental shortcut for exact combined rates.
Korean Freelancer Withholding: 3.3% vs. 8.8% — The Real Difference
When 3.3% business-income or 8.8% other-income withholding may apply, how income is classified, and why final tax requires a separate filing.
The Truth About Exchange Fees: What a 90% Preferential Rate Really Means
Explains base rates, cash-rate spreads, and preferential rates with an assumed KRW 1M example; actual provider rates and fees must be checked.
The Math of Averaging Down: How Much Rebound You Need to Break Even
A -50% loss needs a +100% rebound. We work through the averaging-down formula, how it changes your break-even rebound, and the real break-even after 2026 Korean fees and transaction tax.
Korea's 2027 Minimum Wage (KRW 10,700): Monthly Pay, Holiday Pay, Take-Home
Explains Korea's KRW 10,700 minimum wage for 2027, the 209-hour conversion, holiday-pay and probation rules, plus an illustrative net-pay example using 2026 rates.