Timezone Converter
Convert time between any timezones instantly. Auto-detects your local timezone with full DST support.
World Clock
Understanding Timezones
What Are Timezones?
Timezones are regions of the Earth that observe a uniform standard time. The world is divided into 24 primary timezones, each roughly 15 degrees of longitude wide. Timezones were first adopted in the late 19th century to standardize time for railway schedules and telegraph communications.
What Is UTC?
Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time. It is the successor to Greenwich Mean Time (GMT) and serves as the reference point for all timezones. Each timezone is expressed as an offset from UTC, such as UTC+5:30 for India Standard Time or UTC-5 for Eastern Standard Time.
Daylight Saving Time (DST)
Many regions observe Daylight Saving Time, advancing clocks by one hour during warmer months to extend evening daylight. Not all countries observe DST — notably, most of Asia, Africa, and South America do not. Our converter automatically accounts for DST changes based on the date you select.
Common Timezone Conversions
- EST to PST: Subtract 3 hours (e.g., 12:00 PM EST = 9:00 AM PST)
- EST to GMT: Add 5 hours (e.g., 12:00 PM EST = 5:00 PM GMT)
- PST to JST: Add 17 hours (e.g., 12:00 PM PST = 5:00 AM JST next day)
- GMT to IST: Add 5 hours 30 minutes (e.g., 12:00 PM GMT = 5:30 PM IST)
- CET to EST: Subtract 6 hours (e.g., 12:00 PM CET = 6:00 AM EST)
Tips for Working Across Timezones
- Always specify the timezone when scheduling international meetings
- Use UTC as a common reference when coordinating across multiple timezones
- Be aware of DST transitions — they happen on different dates in different countries
- Consider using the 24-hour clock format to avoid AM/PM confusion
Frequently Asked Questions
How many timezones are there in the world?
There are 24 primary timezones, but in practice there are over 37 different UTC offsets in use, including half-hour and quarter-hour offsets (like India's UTC+5:30 and Nepal's UTC+5:45).
What is the difference between GMT and UTC?
GMT (Greenwich Mean Time) is a timezone, while UTC (Coordinated Universal Time) is a time standard. In practice, they show the same time, but UTC is the standard used for international coordination and does not observe daylight saving time.
Does this tool account for daylight saving time?
Yes. Our converter uses the IANA timezone database through your browser's Intl API, which automatically handles DST transitions for any date you select.
Is my data safe?
Absolutely. All timezone conversions are performed entirely in your browser using JavaScript. No data is sent to any server — your privacy is fully protected.
Can I convert time for a future date?
Yes. Select any date and time in the date picker, and the converter will calculate the correct time in the target timezone, including any DST changes that may occur on that date.