Clock / Stopwatch / World Clock

The World Clock is a versatile time tool that provides three functions in one: current local time display, a stopwatch, and world time for 15 major cities across different time zones. In our interconnected world, keeping track of different time zones is essential for international business calls, coordinating with friends and family abroad, scheduling remote meetings, and planning travel. With 24 standard time zones (plus some offset by 30 or 45 minutes), knowing the exact time in another city helps avoid calling someone at 3 AM or missing a meeting. The world time feature uses the JavaScript Intl API to accurately display current time in 15 major cities spanning all major time zones. This includes cities like Seoul, Tokyo, New York, London, Paris, Sydney, and more. The times automatically adjust for Daylight Saving Time (DST) where applicable. The built-in stopwatch provides precise timing capability with start, stop, and lap functions — useful for workouts, cooking, presentations, and any activity requiring time measurement. All features work entirely in your browser with no server dependency, ensuring instant response and complete privacy.

■ Tab 1: Current Time (시계) Displays your current local time based on your device's clock. Shows hours, minutes, and seconds in a clean, easy-to-read format. The time updates in real-time. ■ Tab 2: Stopwatch (스톱워치) 1. Click 'Start' to begin timing. 2. Click 'Lap' to record split times without stopping (useful for tracking intervals). 3. Click 'Stop' to pause the timer. 4. Click 'Reset' to clear the timer and all lap records. Use cases: • Exercise: Track run times, rest intervals, workout duration • Cooking: Time recipes precisely • Presentations: Monitor speaking time • Games: Time challenges ■ Tab 3: World Time (세계시간) Displays current time for 15 major cities: • Asia: Seoul, Tokyo, Beijing, Singapore, Dubai, Mumbai • Europe: London, Paris, Berlin, Moscow • Americas: New York, Chicago, Los Angeles, São Paulo • Oceania: Sydney Times are shown in each city's local time and automatically account for Daylight Saving Time. Refresh the page to update all times simultaneously.

■ Time Zone Offsets (from UTC) • UTC-8: Los Angeles (PST) / UTC-7 (PDT, Mar-Nov) • UTC-6: Chicago (CST) / UTC-5 (CDT, Mar-Nov) • UTC-5: New York (EST) / UTC-4 (EDT, Mar-Nov) • UTC-3: São Paulo (BRT) • UTC+0: London (GMT) / UTC+1 (BST, Mar-Oct) • UTC+1: Paris, Berlin (CET) / UTC+2 (CEST, Mar-Oct) • UTC+3: Moscow (MSK) • UTC+3:30: Tehran (IRST) • UTC+4: Dubai (GST) • UTC+5:30: Mumbai (IST) • UTC+8: Beijing, Singapore (CST/SGT) • UTC+9: Seoul (KST), Tokyo (JST) • UTC+11: Sydney (AEDT, Oct-Apr) / UTC+10 (AEST) ■ Korea Standard Time (KST) KST = UTC+9 (no Daylight Saving Time) KST = EST + 14 hours = PST + 17 hours KST = GMT/UTC + 9 hours KST = CET + 8 hours ■ Time Difference from Seoul • New York: -14 hours (-13 during US DST) • London: -9 hours (-8 during UK BST) • Paris/Berlin: -8 hours (-7 during EU DST) • Dubai: -5 hours • Mumbai: -3.5 hours • Beijing/Singapore: -1 hour • Tokyo: 0 (same time zone) • Sydney: +2 hours (+1 during Australian DST) • Los Angeles: -17 hours (-16 during US DST) ■ Daylight Saving Time Most of North America: 2nd Sunday of March – 1st Sunday of November Europe: Last Sunday of March – Last Sunday of October Australia: 1st Sunday of October – 1st Sunday of April Korea, Japan, China, Singapore: No DST

■ Quick Time Zone Calculations from Seoul To roughly calculate the time in another city from Seoul (KST): • New York: Seoul time minus 14 hours (13 during DST) • London: Seoul time minus 9 hours (8 during BST) • Los Angeles: Seoul time minus 17 hours (16 during DST) • Tokyo: Same time as Seoul • Beijing: Seoul time minus 1 hour • Sydney: Seoul time plus 2 hours (1 during DST) Example: If it's 3 PM (15:00) in Seoul: • New York: 1 AM (next day during EST) / 2 AM (during EDT) • London: 6 AM (GMT) / 7 AM (BST) • Los Angeles: 10 PM previous day (PST) / 11 PM (PDT) ■ Best Times for International Calls • Seoul → New York: 8-10 PM Seoul = 7-9 AM NY (or 8-10 AM during DST) • Seoul → London: 5-7 PM Seoul = 8-10 AM London (or 9-11 AM BST) • Seoul → LA: 8-10 AM Seoul = 3-5 PM LA previous day ■ International Date Line The International Date Line runs roughly along the 180° meridian in the Pacific. When crossing east-to-west, you add a day; west-to-east, you subtract a day. This is why flights from the US to Korea 'lose a day' and return flights 'gain a day.' ■ Unusual Time Zones • India: UTC+5:30 (30-minute offset) • Nepal: UTC+5:45 (45-minute offset) • Chatham Islands (NZ): UTC+12:45 • Some regions span multiple zones (Russia: 11 time zones, China: officially 1 despite spanning 5)