Tool Guides
In-depth guides to Korean practical tools
How-to lives on the tool page. Background, real-world cases, and law citations live here. Guides, blog, and tools cross-link freely.
Tools — 6 categories
Payroll · Labor
Annual leave · weekly rest · severance · min wage
Finance · Tax
Income tax · loan · compound · VAT · foreign stock
Real Estate
Korean rent cap (5%) verification
Electric (KEC)
Wire size · breaker · voltage drop
Timber · Materials
Rafter · roof · stairs · insulation · materials
Convert · Daily
Pyeong↔m² · percent · JSON↔CSV
Guides — read tools deeper
Wire size — selecting without the table
Estimate cross-section from current, distance, and voltage drop — without the KEC table.
Read guideKorean business registration number — what the checksum tells you
The 1-3-7 weighted checksum that catches fake Korean business numbers before a deal.
Read guideKorean 4-major insurance — 2026 rates and net pay
Pension, health, employment, accident — current rates and exact deductions.
Read guideInsulation R-value · U-value — Korean building code path
Korean zonal U-value limits and the thickness needed with real materials.
Read guideSpan tables — joist, rafter, header limits
Practical NDS-based span limits and the deflection-then-bending check order.
Read guideField Notes — practitioner view
2026-05-30 · ~7 min
Korean Pyeong, Explained — Why 84㎡ is Called 25-Pyeong
Why Korean real estate uses pyeong alongside m², how 84㎡ maps to 25-pyeong, and what exclusive vs supply vs contract area really mean.
2026-05-30 · ~6 min
Korean Business Registration Number — What the Checksum Tells You
The 1-3-7 weighted checksum that catches fake or mistyped Korean business numbers before you sign or wire money.
2026-05-23 · ~8 min
Korean Mortgage: 30-year vs 15-year — Is the longer term really a loss?
Total interest is much lower for 15-year. Yet most people choose 30-year. Once you factor cash flow, inflation, and reinvestment, the math changes.
2026-05-23 · ~7 min
5 most common confusions in Korean progressive income tax
“Crossing a bracket means you earned less in the end” and other myths — debunked with actual numbers.
2026-05-23 · ~6 min
Got a Korean rent increase over 5%? 7 things to do immediately
If your Korean landlord proposes a 6% renewal increase, here are the 7 steps a tenant should take, in order.