Time Zone Guides
How time zones, UTC offsets and daylight saving time work, with the detail you need to plan calls and travel across them.
Vietnam and US Time Difference: Best Times to Call Vietnam
Vietnam is 11 to 17 hours ahead of the US, and only US clocks change. Tables for every US zone, call times, the UTC+7 neighbors and Saigon before 1975.
Read guide →PlanningDubai and US Time Difference: Best Times to Call the UAE
Dubai is 8 or 9 hours ahead of New York, and only US clocks change. Tables for every US zone, the UAE office week in US time, and the Gulf clocks.
Read guide →PlanningBrazil and US Time Difference: São Paulo and Every US Zone
São Paulo is 1 or 2 hours ahead of New York. Brazil dropped summer time in 2019, so only US clocks change. Tables for every US zone and Brazil's four zones.
Read guide →Japan and US Time Difference: Best Times to Call Tokyo
Tokyo is 13 to 19 hours ahead of the US, and only the US changes its clocks. Tables for every US zone, call times, and Japanese holidays in US time.
Read guide →PlanningMexico and US Time Difference: Mexico City, Cancún and the Border
Most of Mexico stopped changing clocks in 2022, so the gap to the US moves twice a year. Tables for Mexico City, Cancún, Tijuana and the border cities.
Read guide →PlanningChina and US Time Difference: Best Times to Call Beijing
Beijing is 12 to 18 hours ahead of the US, and only the US changes its clocks. Tables for every US zone, call times, and the places that share China's clock.
Read guide →PlanningSouth Korea and US Time Difference: Best Times to Call Seoul
Seoul is 13 to 19 hours ahead of the US, and the gap moves twice a year because only the US changes its clocks. Tables for every US zone and call times.
Read guide →PlanningPhilippines and US Time Difference: Every US Zone, Both Seasons
The Philippines is 12 to 18 hours ahead of the US. A table of every US time zone in winter and summer, since only the US changes clocks, plus call times.
Read guide →By regionArizona Time Zone: Same as California in Summer, Denver in Winter
Arizona keeps Mountain Standard Time (UTC−7) all year, so it matches Los Angeles from March to November and Denver in winter. Navajo Nation and call times.
Read guide →By regionIndiana Time Zone: Which Counties Are on Central Time
Most of Indiana is on Eastern time and 12 counties near Chicago and Evansville are on Central. The county list, a town-by-town table and daylight saving.
Read guide →PlanningAustralia Time Difference with the US and UK: Best Times to Call
Sydney is 14 to 16 hours ahead of New York and 9 to 11 ahead of London, and the gap moves four times a year. Dates, tables and call times.
Read guide →By regionStates With Two Time Zones: All 14 and Where the Lines Run
Fourteen US states are split between two time zones, from Florida and Texas to Indiana and Michigan. Where each line runs and the time on the other side.
Read guide →PlanningRecurring Meetings and Daylight Saving Time: Why Your Call Moved
A weekly meeting stays at the same clock time in the time zone it was set in. Everyone else sees it move when the clocks change. See who moves and when.
Read guide →PlanningIs Europe Ahead of the US? Hours by City and Best Call Times
Yes. Paris, Berlin and Rome are 6 hours ahead of New York and 9 ahead of Los Angeles, one less from Mar 14 to Mar 28, 2027. Table for 9 cities and call times.
Read guide →PlanningUK and US Time Difference: Hours by US City and Best Call Times
London is 5 hours ahead of New York and 8 ahead of Los Angeles, one less from Mar 14 to Mar 28, 2027. Table for every US zone and the best hours to call.
Read guide →BasicsIs Daylight Saving Time Permanent Now? Places That Stopped
Not in the US: the Senate has not passed the Sunshine Protection Act. B.C., Alberta, Manitoba and Morocco stopped changing clocks in 2026. See the full list.
Read guide →PlanningUS to India Time Difference and the Best Time to Call
India is 9½ to 10½ hours ahead of New York and 12½ to 13½ ahead of Los Angeles. The best call windows, a city table and the March and November changes.
Read guide →BasicsUTC Offset Explained: UTC vs GMT, and How to Convert Time
A UTC offset like UTC−5 is one number. A time zone like America/New_York is a set of rules that changes it. How to read offsets and convert between cities.
Read guide →BasicsWhen Does Daylight Saving Time Start? March 14, 2027
US clocks spring forward on Sunday, March 14, 2027. UK clocks go forward on Sunday, March 28. Clock change dates for the US, UK, Europe, Australia and New Zealand.
Read guide →PlanningScheduling Meetings Across Time Zones: A 6-Step Checklist
A practical checklist for planning calls across time zones: overlap windows, fair rotation, clear invitations and common mistakes.
Read guide →BasicsHalf-Hour Time Zones, 45-Minute Offsets and the Date Line
Why India, Iran and Newfoundland use 30-minute offsets and Nepal 45, how UTC+14 and UTC−12 put three dates on Earth at once, and why zones follow borders.
Read guide →By regionUS Time Zones: Eastern, Central, Mountain, Pacific and More
The US time zones from Eastern to Hawaii, when clocks change, which places skip daylight saving time, and how to schedule calls between coasts.
Read guide →By regionEurope Time Zones: WET, CET and EET Are One Hour Apart
EET is one hour ahead of CET, and CET one hour ahead of WET and the UK. Which countries use each zone, when clocks change, and the places that differ.
Read guide →By regionAsia Time Zones: UTC Offsets by Country and the Pacific
Asian countries use offsets from UTC+2 to UTC+9, with odd ones like India (UTC+5:30) and Nepal (UTC+5:45). Offsets by country, and the Pacific.
Read guide →TravelHow to Avoid Jet Lag: Why Flying East Is Harder
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.
Read guide →HistoryWho Invented Time Zones, and When Were They Created?
Charles Dowd and Sandford Fleming proposed them, and US and Canadian railroads switched on November 18, 1883. How sun time became the time zones we use.
Read guide →BasicsEST vs EDT and Other Time Zone Abbreviations Explained
EST is Eastern Standard Time (UTC−5), EDT the summer version (UTC−4). CST and IST each have several meanings. How to write times clearly.
Read guide →PlanningTime Zone Overlap: Shared Work 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.
Read guide →By regionAfrica Time Zones: Every Country's UTC Offset in One Table
No, African countries don't share one time. A table of all 54 countries by offset (6 offsets, UTC−1 to UTC+4), plus Egypt's daylight saving time and the Middle East.
Read guide →By regionCanada Time Zones, Plus Mexico, Brazil and South America
Canada has six time zones, Mexico four, Brazil four. See which countries change their clocks, which stopped, and how to schedule across the Americas.
Read guide →By regionRussia Time Zones: Table of All 11, UTC+2 to UTC+12, No DST
Russia has 11 time zones, UTC+2 in Kaliningrad to UTC+12 in Kamchatka. A table of every zone with a city and offset, gaps from Moscow, and no DST since 2014.
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