Time Zone Guides
Practical explanations of how time zones, UTC offsets and daylight saving time work, written to help you plan calls, travel and work across the world.
UTC and Time Zone Offsets: How to Calculate Time Differences
Learn what UTC is, how to read offsets like UTC+5:30, and how to convert time between any two cities step by step.
Daylight Saving Time Explained: Why Time Differences Change
Which countries use daylight saving time, when clocks change in the US, Europe and Australia, and why gaps between cities shift for a few weeks each year.
How to Schedule Meetings Across Time Zones
A practical checklist for planning calls across time zones: overlap windows, fair rotation, clear invitations and common mistakes.
Unusual Time Zones: Half-Hour Offsets, the Date Line and More
Why some countries use 30- or 45-minute offsets, how UTC+14 and UTC−12 can put three dates on Earth at once, and why time zones follow borders instead of maps.
Time Zones in the United States: Zones, DST and Exceptions
The US time zones from Eastern to Hawaii, when clocks change, which places skip daylight saving time, and how to schedule calls between coasts.
Time Zones in Europe: WET, CET, EET and the Exceptions
Europe uses three main time zones. Learn which countries use which, when clocks change, and which places, such as Iceland and Turkey, do not follow the pattern.
Time Zones in Asia and the Pacific: A Regional Guide
How time zones work across Asia and Oceania: China and India on one clock, multi-zone countries, half-hour offsets and the few places with daylight saving.
Jet Lag and Time Zones: How to Plan Your Travel
General tips for handling jet lag: why flying east is harder, and how to adjust your sleep and light exposure before and after a trip.
How Time Zones Were Invented: A Short History
From local sun time to railway time, the 1884 Prime Meridian Conference, daylight saving time and UTC: how the world ended up with the time zones we use today.
EST, CST, IST: Why Time Zone Abbreviations Confuse
Time zone abbreviations such as CST, IST and BST each mean different things in different countries. See common conflicts and how to write times without confusion.
Overlapping Business Hours Between Major Cities
See how many hours of a 09:00-17:00 working day overlap between ten major cities, in January and in July, calculated with daylight saving rules.
Time Zones in Africa and the Middle East
Africa and the Middle East use few daylight saving changes. See the main offsets, the exceptions such as Egypt and Morocco, and the weekends that differ from Europe.
Time Zones in Canada, Latin America and the Caribbean
Canada has six time zones, Mexico four, Brazil four. See which countries change their clocks, which stopped, and how to schedule across the Americas.