Time Zone Cheatsheet
Instant direct answers, mental conversion shortcuts, and offset lookup tables across North America, Europe, and Asia.
Global Timezone Offset Matrix
Use this quick-reference matrix to compare standard and daylight saving coordinates against US Eastern Time:
| Time Zone Region | Standard Offset | Daylight Saving | Relation to Eastern Time |
|---|---|---|---|
| UTC / GMT | GMT (UTC+0) | BST (UTC+1) | EST is 5h behind GMT (4h in summer) |
| Eastern Time (US/CA) | EST (UTC-5) | EDT (UTC-4) | Baseline reference |
| Central Time (US/CA) | CST (UTC-6) | CDT (UTC-5) | 1 hour behind Eastern Time |
| Mountain Time (US/CA) | MST (UTC-7) | MDT (UTC-6) | 2 hours behind Eastern Time |
| Pacific Time (US/CA) | PST (UTC-8) | PDT (UTC-7) | 3 hours behind Eastern Time |
| Central Europe | CET (UTC+1) | CEST (UTC+2) | CET is 6 hours ahead of EST |
| India Standard Time | IST (UTC+5:30) | No DST | IST is 10h 30m ahead of EST |
| Japan & Korea | JST/KST (UTC+9) | No DST | JST is 14 hours ahead of EST |
| Australian Eastern | AEST (UTC+10) | AEDT (UTC+11) | AEST is 15 hours ahead of EST |
Mental Math Shortcuts for Fast Conversions
GMT → EST (Winter)
Subtract 5 hours from 24h GMT time. E.g., 15:00 GMT − 5 = 10:00 AM EST.
EST → GMT (Winter)
Add 5 hours to EST time. E.g., 2:00 PM EST (14:00) + 5 = 19:00 (7:00 PM GMT).
EST → PST
Always subtract 3 hours. Both coastal zones shift DST in unison on the same date.
Explore Interactive Time Zone Converters
Frequently Asked Questions
How do I instantly calculate GMT to EST in my head?
During winter (standard time), subtract 5 hours from GMT: e.g., 17:00 GMT − 5 = 12:00 PM EST. During summer (daylight saving time), subtract 4 hours: e.g., 17:00 BST − 4 = 1:00 PM EDT.
How do I calculate US coastal time differences?
The United States spans four contiguous time zones with 1-hour steps: Eastern (0) → Central (−1h) → Mountain (−2h) → Pacific (−3h). When it is 12:00 PM in New York (EST), it is 11:00 AM in Chicago (CST), 10:00 AM in Denver (MST), and 9:00 AM in Los Angeles (PST).
Why does the time difference between the US and Europe change for 2 weeks every year?
The United States begins Daylight Saving Time on the second Sunday of March, whereas the European Union transitions on the last Sunday of March. This causes transatlantic time differences to temporarily shrink by 1 hour for approximately 2 to 3 weeks in the spring and autumn.
Which major regions never observe Daylight Saving Time?
Large global economies that observe standard time year-round include Arizona, Hawaii, Japan, China, India, Singapore, the UAE, and most of South America and Africa.