세계 시계 & 시간대 변환기

Coordinated Universal Time (UTC) is the world's primary time standard. Time zones are defined as offsets from UTC, ranging from UTC-12 to UTC+14. Most zones are whole-hour offsets, but some countries use 30-minute (India: UTC+5:30) or even 45-minute offsets (Nepal: UTC+5:45). Korea Standard Time (KST) is UTC+9, the same as Japan Standard Time (JST).

About 70 countries observe Daylight Saving Time, advancing clocks by one hour in spring and reversing in autumn. Most of Europe, North America, and parts of Oceania use DST, while most of Asia, Africa, and South America do not. DST transitions can temporarily change the time difference between cities — for example, New York is normally 14 hours behind Seoul, but only 13 hours during US summer.

When scheduling international meetings, identify the overlapping business hours (typically 9 AM–6 PM) for all participants. A good rule of thumb: for Asia-US meetings, early morning US time works best. For Asia-Europe meetings, afternoon European time overlaps with evening Asian time. Always confirm the current DST status for each location before setting a time.

The most important business time zones include EST/EDT (New York, UTC-5/-4), GMT/BST (London, UTC+0/+1), CET/CEST (Berlin/Paris, UTC+1/+2), IST (Mumbai, UTC+5:30), CST (Beijing/Shanghai, UTC+8), KST/JST (Seoul/Tokyo, UTC+9), and AEDT/AEST (Sydney, UTC+10/+11). Knowing these core zones helps you quickly estimate time differences for business communication.