Time Zone Calculator
Convert any time between world time zones. Enter a date and time in the source zone and get the exact local time in the target zone, with automatic Daylight Saving Time handling.
Enter your values above to see the results.
Tips & Notes
- ✓When scheduling international meetings, use UTC as the common reference point and let each participant convert to their local time — this avoids confusion about who adjusts for Daylight Saving Time.
- ✓Phoenix, Arizona does not observe Daylight Saving Time — it stays on MST (UTC-7) year-round. During summer it shares UTC-7 with California (PDT), but in winter it is 1 hour ahead of California (PST, UTC-8).
- ✓India (UTC+5:30) and Nepal (UTC+5:45) use non-standard half and quarter-hour offsets — always verify to the minute when scheduling with these regions.
- ✓The International Date Line runs through the Pacific at approximately 180 degrees longitude. Crossing it westward adds a day; eastward subtracts a day.
- ✓Always specify whether a time is Standard or Daylight when communicating across regions with different DST transition dates — 2 PM Eastern can mean UTC-5 or UTC-4 depending on the season.
Common Mistakes
- ✗Using the standard time offset year-round without adjusting for Daylight Saving — New York is UTC-5 in winter and UTC-4 in summer. Using the wrong offset creates a 1-hour error for half the year.
- ✗Assuming all areas in the same country share one time zone — the US has 6 time zones, Australia has 3 standard zones, and Russia has 11.
- ✗Forgetting that DST transitions happen on different dates in different regions — during the weeks between EU and US transitions in spring and fall, the effective offset between them differs by 1 hour from normal.
- ✗Treating UTC and GMT as synonymous without checking DST — GMT is a time zone that becomes BST (UTC+1) in summer. UTC is a time standard that never changes. They are the same only during UK winter.
- ✗Converting times near midnight without accounting for the date change — 11 PM New York is 4 AM the next day in Paris. Calculations that ignore the date component produce the right clock time on the wrong day.
Time Zone Calculator Overview
A time zone calculator converts a specific date and time from one time zone to another, accounting for UTC offsets, Daylight Saving Time rules, and half-hour or quarter-hour zones. It is essential for scheduling international meetings, booking flights across time zones, coordinating remote teams, and verifying contract or delivery time stamps in the correct local time.
Time zone conversion formula:
Target Time = Source Time + (Target UTC Offset − Source UTC Offset)
EX: Meeting at 3:00 PM New York (EST, UTC−5). Paris time? UTC+1 − (−5) = +6 hours. 3:00 PM + 6h = 9:00 PM Paris (CET)Major world time zones — UTC offsets:
| Time Zone | UTC Offset (Standard) | UTC Offset (DST) | Cities |
|---|---|---|---|
| Eastern (ET) | UTC−5 | UTC−4 | New York, Toronto, Miami |
| Central (CT) | UTC−6 | UTC−5 | Chicago, Dallas, Mexico City |
| Mountain (MT) | UTC−7 | UTC−6 | Denver, Phoenix, Calgary |
| Pacific (PT) | UTC−8 | UTC−7 | Los Angeles, Seattle, Vancouver |
| GMT/UTC | UTC+0 | UTC+1 (BST) | London, Dublin, Lisbon |
| Central European (CET) | UTC+1 | UTC+2 (CEST) | Paris, Berlin, Rome, Madrid |
| Gulf Standard (GST) | UTC+4 | No DST | Dubai, Abu Dhabi |
| India Standard (IST) | UTC+5:30 | No DST | Mumbai, Delhi, Bangalore |
| China Standard (CST) | UTC+8 | No DST | Beijing, Shanghai, Shenzhen |
| Japan Standard (JST) | UTC+9 | No DST | Tokyo, Osaka, Kyoto |
| Australian Eastern (AET) | UTC+10 | UTC+11 | Sydney, Melbourne, Brisbane |
| Time Zone | UTC Offset | Country/Region |
|---|---|---|
| India Standard Time (IST) | UTC+5:30 | India, Sri Lanka |
| Nepal Time (NPT) | UTC+5:45 | Nepal |
| Iran Standard Time (IRST) | UTC+3:30 | Iran |
| Newfoundland Time (NST) | UTC−3:30 | Newfoundland, Canada |
| Australian Central (ACST) | UTC+9:30 | Adelaide, Darwin |
| Chatham Islands (CHAST) | UTC+12:45 | New Zealand territory |
Frequently Asked Questions
Find the UTC offset for each zone. Subtract the source offset from the target and add to the source time. Example: 10 AM Chicago (CST, UTC-6) to Tokyo (JST, UTC+9): difference = +9 - (-6) = +15 hours. 10 AM + 15 hours = 1 AM the next day in Tokyo.
UTC is the universal time standard maintained by atomic clocks and never changed for Daylight Saving. GMT is a time zone used in the UK during winter. During British Summer Time (BST), the UK is at UTC+1. For technical purposes, always use UTC — GMT can be ambiguous because of its overlap with BST.
No. India Standard Time (IST, UTC+5:30) is observed year-round with no seasonal adjustment. India, China, Japan, and most of the Middle East and Southeast Asia do not observe DST. When calculating differences with regions that do observe DST, the effective offset changes twice a year even though the non-DST side stays constant.
The International Date Line runs roughly along 180 degrees longitude in the Pacific. Moving westward across it advances the date by 1 day; moving eastward subtracts a day. It zigzags to avoid splitting countries. Crossing it is why a flight from Los Angeles to Sydney can arrive the day after tomorrow despite taking only 15 hours.
Time zones were originally defined as 15 degrees of longitude = 1 hour. However, many countries chose offsets matching their geographic situation. India chose UTC+5:30 to keep the whole country in one zone while maintaining solar time alignment. Nepal chose UTC+5:45 to distinguish itself from India. Australia Central uses UTC+9:30 to align Adelaide with other major cities.
Find the city UTC offset (accounting for current DST status). Add or subtract from current UTC time. Example: current UTC = 18:00. Sydney in summer = UTC+11: 18:00 + 11 = 05:00 next day. Sydney in winter = UTC+10: 18:00 + 10 = 04:00 next day. This calculator handles DST automatically for current and future dates.