Time Zone Converter & World Time Zones
Convert any moment between hundreds of IANA time zones with up-to-date daylight saving rules. Check the most popular city pairs, browse current offsets for major cities, or try the embedded converter below.
Popular Conversions
- New York → LondonAmerica/New_York → Europe/London
- New York → Los AngelesAmerica/New_York → America/Los_Angeles
- New York → ParisAmerica/New_York → Europe/Paris
- New York → TokyoAmerica/New_York → Asia/Tokyo
- London → ParisEurope/London → Europe/Paris
- London → DubaiEurope/London → Asia/Dubai
- London → TokyoEurope/London → Asia/Tokyo
- Paris → BerlinEurope/Paris → Europe/Berlin
- Chicago → New YorkAmerica/Chicago → America/New_York
- Dubai → MumbaiAsia/Dubai → Asia/Kolkata
- Shanghai → TokyoAsia/Shanghai → Asia/Tokyo
- UTC → New YorkUTC → America/New_York
Major Cities & Current Offsets
EST/EDT — observes DST
PST/PDT — observes DST
CST/CDT — observes DST
GMT/BST — observes DST
CET/CEST — observes DST
CET/CEST — observes DST
GST — UTC+04:00, no DST
IST — UTC+05:30, no DST
CST — UTC+08:00, no DST
JST — UTC+09:00, no DST
AEST/AEDT — observes DST (Southern Hemisphere)
BRT — UTC-03:00, no DST since 2019
EET — UTC+02:00, reintroduced DST in 2023
WAT — UTC+01:00, no DST
Time Zone Converter
All Time Zone Tools
- Current Unix TimestampLive Unix time in seconds and milliseconds. Copy, pause or refresh.
- Timezone ConverterConvert time between zones and compare cities side by side.
- UTC ConverterConvert between local time and UTC in any time zone.
- Time Zone Offset CalculatorCompare the UTC offset of two time zones and the gap between them.
- World ClockLive local time in several cities at once, with day and night shown.
- Business Hours ConverterCompare working hours across time zones and find the overlap for meetings.
- Timezone Travel SimulatorVisual timeline for debugging global events across regions.
Guides
- What Is Unix Time?A plain-language explanation of Unix time, the epoch and why programs count time this way.4 min read
- Time Zones and DST for DevelopersThe handful of rules that prevent most time zone bugs, with the daylight saving edge cases explained.5 min read
- UTC vs GMT: What Is the Difference?Why UTC and GMT usually show the same time, how they differ technically, and which one to use in software.3 min read
Why Use Castov?
Free
Every tool is free to use, with no usage limits and no paid tier.
Fast
Small pages and almost no JavaScript, so results appear the moment you press Convert.
Private
The converters run in your browser, so what you type stays on your device. The few tools that use our servers, such as Env Vault, say so on their page.
Frequently Asked Questions
Is Castov really free?
Is my data sent to a server?
What is a Unix timestamp?
Should I use seconds or milliseconds?
Which time zones are supported?
Need to compare multiple zones?
Use the World Clock tool to see the same instant across up to eight time zones at once, including DST.