Time Zones Made Simple
Booking a call with someone abroad, catching a flight, watching a live event: here's how time zones actually work, and how to never miss a meeting again.
UTC and offsets
The world sets its clocks relative to UTC (Coordinated Universal Time), essentially the time at 0° longitude, near London. Each place has an offset: how many hours ahead (+) or behind (−) UTC it is.
| Place | Standard offset |
|---|---|
| Los Angeles | UTC−8 |
| New York | UTC−5 |
| London | UTC+0 |
| Paris, Berlin | UTC+1 |
| India | UTC+5:30 |
| Tokyo | UTC+9 |
| Sydney | UTC+10 |
Not every offset is a whole hour: India is +5:30 and Nepal +5:45.
Daylight saving time
Many countries move their clocks forward an hour in summer (“spring forward, fall back”). So New York is UTC−5 in winter but UTC−4 in summer.
The tricky weeks: the US and Europe change on different dates, so for a few weeks each spring and autumn the gap between New York and London is 4 hours instead of 5.
The southern hemisphere does it the other way round: Sydney's clocks go forward in October.
Scheduling across time zones
- When you write a time for others, always include the zone: “3 pm ET / 8 pm UK”.
- Calendar invites adjust automatically to each person's zone. Let the calendar do the maths.
- Crossing the International Date Line (in the Pacific) changes the date: flying west you skip a day; flying east you live one twice.
Uses your browser's up-to-date time zone rules, including daylight saving.