The world uses UTC (Coordinated Universal Time) as the global time standard. All time zones are expressed as UTC offset. Sri Lanka is UTC+5:30, India UTC+5:30, UAE UTC+4, UK UTC+0 (UTC+1 in summer BST), USA Eastern UTC-5 (UTC-4 in summer). The world is divided into 24 major time zones, though some regions use 30 or 45-minute offsets.
📂 Daily Life
🌎 World Clock
See the current time in 20 major cities around the world simultaneously. Updated live every second. Perfect for international calls, meetings, and travel planning.
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✅ Trusted Tool
The 365tool.net World Clock uses standard UTC offset calculations. Daylight saving time is not automatically applied — check local DST status for accuracy during summer months. Free for international travellers and remote workers. No sign-up needed.
🤔 How Does This Work?
The World Clock uses real-time JavaScript date functions:
Gets current UTC time from your device's system clock
Adds each city's UTC offset to get local time
Updates every second for live display
Detects whether each location is currently daytime or nighttime
❓ Frequently Asked Questions
What is UTC?▼
UTC (Coordinated Universal Time) is the world's primary time standard. It is the basis for civil time and time zones worldwide. All time zones are expressed as UTC+ or UTC-. UTC does not change for daylight saving time. It replaced GMT (Greenwich Mean Time) in 1960 but they are nearly identical for most purposes.
Why does India use UTC+5:30 instead of UTC+5 or UTC+6?▼
India chose a half-hour offset to cover the entire country in a single time zone while avoiding being too far from solar noon at the eastern and western extremes of the country. Sri Lanka also uses UTC+5:30. Other half-hour zones include Iran (UTC+3:30), Afghanistan (UTC+4:30), and Australia (UTC+9:30 for central). Nepal uses UTC+5:45.
What is daylight saving time?▼
DST is the practice of advancing clocks 1 hour in spring and reverting in autumn to extend evening daylight. Widely used in USA, Canada, Europe, Australia. NOT used in India, Sri Lanka, UAE, China, Japan, and most of Asia and Africa. During DST, UK changes from UTC+0 to UTC+1, USA Eastern from UTC-5 to UTC-4.
What is the International Date Line?▼
The International Date Line runs roughly along the 180° meridian in the Pacific Ocean. Crossing it eastward moves you one day back; westward moves you one day forward. This is necessary because time zones circle the globe — without the date line, you would gain or lose a full day during round-the-world travel. The line zigzags to keep island nations on the same date.
What are the busiest time zone overlaps for international business?▼
Best overlap for Asia-Europe business: 9 AM London = 2:30 PM Colombo/Mumbai. Best Asia-Americas overlap: early morning US time = late evening Asia time. The most globally connected business window is approximately 8-10 AM UK time, which overlaps with both East Asian morning (late) and US East Coast afternoon.
UTC (Coordinated Universal Time) is the world's primary time standard. It is the basis for civil time and time zones worldwide. All time zones are expressed as UTC+ or UTC-. UTC does not change for daylight saving time. It replaced GMT (Greenwich Mean Time) in 1960 but they are nearly identical for most purposes.
Why does India use UTC+5:30 instead of UTC+5 or UTC+6?▼
India chose a half-hour offset to cover the entire country in a single time zone while avoiding being too far from solar noon at the eastern and western extremes of the country. Sri Lanka also uses UTC+5:30. Other half-hour zones include Iran (UTC+3:30), Afghanistan (UTC+4:30), and Australia (UTC+9:30 for central). Nepal uses UTC+5:45.
What is daylight saving time?▼
DST is the practice of advancing clocks 1 hour in spring and reverting in autumn to extend evening daylight. Widely used in USA, Canada, Europe, Australia. NOT used in India, Sri Lanka, UAE, China, Japan, and most of Asia and Africa. During DST, UK changes from UTC+0 to UTC+1, USA Eastern from UTC-5 to UTC-4.
What is the International Date Line?▼
The International Date Line runs roughly along the 180° meridian in the Pacific Ocean. Crossing it eastward moves you one day back; westward moves you one day forward. This is necessary because time zones circle the globe — without the date line, you would gain or lose a full day during round-the-world travel. The line zigzags to keep island nations on the same date.
What are the busiest time zone overlaps for international business?▼
Best overlap for Asia-Europe business: 9 AM London = 2:30 PM Colombo/Mumbai. Best Asia-Americas overlap: early morning US time = late evening Asia time. The most globally connected business window is approximately 8-10 AM UK time, which overlaps with both East Asian morning (late) and US East Coast afternoon.