Time Zone Calculator – Convert Time Between Different Time Zones
Convert any time from one time zone to another instantly. See live world clock times for major cities, check UTC offsets, and understand daylight saving time free and no sign-up required.
This time zone calculator converts a specific date and time from one UTC offset to another. It supports all 39 standard UTC offsets including half-hour and quarter-hour zones like India (UTC+5:30) and Nepal (UTC+5:45).
- Convert time zones with precise minute-level offset arithmetic
- Swap zones with one click to reverse the conversion
- Day change alert when the result falls on a different date
- DST indicator for zones that observe daylight saving time
- Live world clock for 12 major cities, updated every second
- Copy result to paste into emails or calendar invites
| Zone | UTC | DST |
|---|---|---|
| Eastern Time (ET) | UTC-05:00 | Yes |
| Central Time (CT) | UTC-06:00 | Yes |
| Mountain Time (MT) | UTC-07:00 | Yes |
| Pacific Time (PT) | UTC-08:00 | Yes |
| GMT / London | UTC+00:00 | Yes |
| CET / Paris | UTC+01:00 | Yes |
| Moscow (MSK) | UTC+03:00 | No |
| Pakistan (PKT) | UTC+05:00 | No |
| India (IST) | UTC+05:30 | No |
| China (CST) | UTC+08:00 | No |
| Japan (JST) | UTC+09:00 | No |
| Sydney (AEDT) | UTC+10:00 | Yes |
| Location | Offset |
|---|---|
| India / Sri Lanka | UTC+05:30 |
| Nepal | UTC+05:45 |
| Iran | UTC+03:30 |
| Afghanistan | UTC+04:30 |
| Myanmar | UTC+06:30 |
| Newfoundland | UTC-03:30 |
| Marquesas Islands | UTC-09:30 |
| Chatham Islands | UTC+12:45 |
How to Use the Time Zone Calculator
To convert a time zone, enter your date and time, select the source time zone in the From dropdown, select the target time zone in the To dropdown, and click Convert Time. The result shows the converted time, full date, UTC offsets for both zones, and a warning if the conversion crosses into a different calendar day. The World Clock tab shows live current times for 12 major cities, updated every second.
Converting a Time Between Two Time Zones
Open the Time Zone Converter tab. Pick the date, enter the time in 24-hour HH:MM format, choose your source zone, choose your target zone, and click Convert Time. Results are accurate to the minute including all fractional-hour zones such as India Standard Time (UTC+5:30) and Nepal Time (UTC+5:45).
Using the Swap Button
Click Swap Zones to reverse the From and To time zones instantly. Use this to verify a conversion in both directions for example, confirm that 10:00 London correctly converts back to 15:00 Karachi before sending a meeting invite.
Reading the World Clock
Switch to the World Clock tab to see live times for New York, London, Paris, Dubai, Karachi, Delhi, Beijing, Tokyo, Sydney, Los Angeles, São Paulo, and Moscow. Each card shows HH:MM:SS, the full date, the UTC offset, and a sun or moon icon for daytime or night. Click any city card to load that zone into the converter.
Understanding the Day Change Alert
A large UTC offset difference can push a converted time past midnight into a different calendar day. The calculator detects this and shows an amber warning so you never accidentally schedule something a day off.
Current Time in Major Cities
Each entry below states the city's UTC offset, its standard time zone abbreviation, whether it observes Daylight Saving Time, and the current season offset. Use the World Clock tab for a live reading.
New York, USA
Eastern Time (ET)
Standard: UTC-5:00
DST: UTC-4:00 (EDT in summer)
Los Angeles, USA
Pacific Time (PT)
Standard: UTC-8:00
DST: UTC-7:00 (PDT in summer)
London, UK
Greenwich Mean Time (GMT)
Standard: UTC+0:00
DST: UTC+1:00 (BST in summer)
Paris, France
Central European Time (CET)
Standard: UTC+1:00
DST: UTC+2:00 (CEST in summer)
Moscow, Russia
Moscow Standard Time (MSK)
Standard: UTC+3:00
No DST — fixed year-round
Dubai, UAE
Gulf Standard Time (GST)
Standard: UTC+4:00
No DST — fixed year-round
Karachi, Pakistan
Pakistan Standard Time (PKT)
Standard: UTC+5:00
No DST — fixed year-round
Delhi, India
India Standard Time (IST)
Standard: UTC+5:30
No DST — fixed year-round
Dhaka, Bangladesh
Bangladesh Standard Time (BST)
Standard: UTC+6:00
No DST — fixed year-round
Beijing, China
China Standard Time (CST)
Standard: UTC+8:00
No DST — fixed year-round
Tokyo, Japan
Japan Standard Time (JST)
Standard: UTC+9:00
No DST — fixed year-round
Sydney, Australia
Australian Eastern Time (AET)
Standard: UTC+10:00
DST: UTC+11:00 (AEDT in summer)
When People Use a Time Zone Calculator
Professional Uses
- Remote teams: Schedule a stand-up that works across all time zones
- Client calls: Confirm a meeting time for an overseas client
- Software releases: Coordinate deploys across global engineering teams
- Finance: Know when a foreign stock market opens in local time
- Legal deadlines: Confirm whether a UTC midnight deadline has passed locally
Personal Uses
- Travel planning: Arrival time in local time at your destination
- Live events: Watch a sports match or concert broadcast in your time
- Family abroad: Know when it is a reasonable hour to call
- Gaming: Server reset or tournament start in your local time
- Online auctions: Auction end time converted to your zone
What Is UTC? What Is GMT? Key Definitions
UTC (Coordinated Universal Time) is the primary time standard the world uses to regulate clocks. It is maintained by a network of atomic clocks and does not change for Daylight Saving Time. Every time zone on Earth is defined as a fixed offset from UTC. GMT (Greenwich Mean Time) is the mean solar time observed at the Royal Observatory in Greenwich, London. GMT and UTC show the same clock value, but UTC is the scientific standard while GMT is now only a time zone name used in parts of Africa and Western Europe.
| Term | Full Name | What It Is | DST? |
|---|---|---|---|
| UTC | Coordinated Universal Time | Global atomic-clock time standard. The reference for all offsets. | Never |
| GMT | Greenwich Mean Time | Time zone for UK (winter), Iceland, Ghana, Senegal. | Not itself UK switches to BST in summer |
| UTC offset | e.g. UTC+5:30 | Hours and minutes a region is ahead of or behind UTC. | Offset can change ±1 hr during DST |
| DST | Daylight Saving Time | Seasonal 1-hour clock advance used in ~70 countries. | Yes this is DST itself |
| Standard Time | e.g. EST, IST, PKT | The fixed UTC offset without any DST adjustment. | No |
| Summer Time | e.g. EDT, BST, CEST | The UTC offset during DST standard offset plus 1 hour. | Yes |
Daylight Saving Time — Which Countries Use It?
Daylight Saving Time (DST) is the practice of setting clocks forward by one hour in spring and back by one hour in autumn. About 70 countries use it. Roughly 140 countries do not. The purpose is to shift an extra hour of daylight into the evening during longer summer days.
Northern Hemisphere DST
Clocks go forward in late March–early April and back in late October–early November. Affects the United States, Canada, most of Europe, parts of the Middle East, and Mexico.
Spring forward → Autumn backSouthern Hemisphere DST
Clocks go forward in September–October and back in March–April (opposite seasons). Affects Australia, New Zealand, Chile, Paraguay, and parts of Brazil.
Spring forward → Autumn backNo DST Regions
China, Japan, India, Pakistan, Bangladesh, most of Africa, Southeast Asia, and equatorial countries keep the same UTC offset year-round. No clock changes.
Fixed offset all year| Country | Uses DST? | Standard Offset | Summer Offset |
|---|---|---|---|
| United States (ET) | Yes | UTC-5:00 (EST) | UTC-4:00 (EDT) |
| United Kingdom | Yes | UTC+0:00 (GMT) | UTC+1:00 (BST) |
| Germany / France | Yes | UTC+1:00 (CET) | UTC+2:00 (CEST) |
| Australia (Sydney) | Yes | UTC+10:00 (AEST) | UTC+11:00 (AEDT) |
| Pakistan | No | UTC+5:00 (PKT) | UTC+5:00 (no change) |
| India | No | UTC+5:30 (IST) | UTC+5:30 (no change) |
| China | No | UTC+8:00 (CST) | UTC+8:00 (no change) |
| Japan | No | UTC+9:00 (JST) | UTC+9:00 (no change) |
| Russia (Moscow) | No | UTC+3:00 (MSK) | UTC+3:00 (no change) |
| UAE / Dubai | No | UTC+4:00 (GST) | UTC+4:00 (no change) |
Time Zones by Region
There are 39 UTC offsets in use worldwide, ranging from UTC-12:00 (Baker Island) to UTC+14:00 (Line Islands, Kiribati). Most follow whole-hour intervals but eight zones use 30-minute or 45-minute offsets for historical or geographic reasons.
| Region | UTC Range | Notable Zones |
|---|---|---|
| North America | UTC-10 to UTC-3:30 | Hawaii (UTC-10), Alaska (UTC-9), Pacific (UTC-8), Mountain (UTC-7), Central (UTC-6), Eastern (UTC-5) |
| South America | UTC-5 to UTC-3 | Colombia/Peru (UTC-5), Brazil/Chile (UTC-3), Argentina (UTC-3) |
| Europe | UTC-1 to UTC+3 | GMT/London (UTC+0), CET/Paris/Berlin (UTC+1), EET/Athens (UTC+2), Moscow (UTC+3) |
| Africa | UTC+0 to UTC+3 | Accra/Abidjan (UTC+0), Lagos/Kinshasa (UTC+1), Cairo/Johannesburg (UTC+2), Nairobi (UTC+3) |
| Middle East | UTC+2 to UTC+4:30 | Israel (UTC+2), Kuwait/Riyadh (UTC+3), Tehran (UTC+3:30), Dubai (UTC+4), Kabul (UTC+4:30) |
| South Asia | UTC+5 to UTC+5:45 | Karachi/Islamabad (UTC+5), Delhi/Mumbai (UTC+5:30), Kathmandu (UTC+5:45) |
| East/SE Asia | UTC+6 to UTC+9 | Dhaka (UTC+6), Bangkok/Jakarta (UTC+7), Beijing/Singapore (UTC+8), Tokyo/Seoul (UTC+9) |
| Oceania | UTC+9:30 to UTC+14 | Adelaide (UTC+9:30), Sydney (UTC+10), Auckland (UTC+12), Line Islands (UTC+14) |
Common Time Zone Mistakes to Avoid
Ignoring the day change
A large UTC offset difference can push the converted time past midnight into a different calendar day. Always check the full date in the result not just the clock time.
Assuming all regions observe DST
India, China, Japan, Pakistan, and most of the Middle East do not change their clocks. A meeting time that works in winter may shift by an hour in summer for colleagues in DST-observing regions.
Confusing UTC and GMT
UTC and GMT show the same clock reading today, but GMT is technically a time zone. Use UTC offsets for all international scheduling to avoid ambiguity.
Using 12-hour format without AM/PM clarity
12:00 PM and 12:00 AM are the most commonly misread times. This calculator uses 24-hour format (00:00–23:59) to eliminate AM/PM confusion entirely.
Not re-checking around DST transition dates
The US, UK, and EU change their clocks on different weekends. A meeting scheduled across those weekends may shift by an hour on one side but not the other. Always re-verify near transition dates.
Treating fractional zones as full-hour offsets
India is UTC+5:30, not UTC+5. Nepal is UTC+5:45. Rounding these to the nearest hour introduces a 30 or 45-minute error. This calculator uses exact minute-level offsets for all 39 zones.
Tips for Accurate Time Zone Conversions
- Always specify the date the same offset can mean different times across DST periods
- Use 24-hour format to remove all AM/PM ambiguity
- Use Swap Zones to verify both directions of a conversion before sending invites
- Check the day change badge a converted time can fall on the previous or next calendar day
- Re-check recurring meetings after each DST transition date (US, UK, and EU change clocks on different Sundays)
- Use the World Clock tab to confirm whether a city is currently in business hours before calling
How the Conversion Works
Every time zone is stored as a fixed UTC offset in whole minutes. To convert, the calculator subtracts the source offset from the target offset and adds the difference in minutes to the input time using addMinutes from the date-fns library. Using minutes instead of hours means fractional zones like UTC+5:30 (330 min) and UTC+5:45 (345 min) are handled with zero rounding error. The World Clock applies each city's offset to the browser's current UTC time independently and updates every second via a setInterval.
Frequently Asked Questions
Convert Any Time Zone Instantly
Whether you need to schedule a meeting across continents, figure out when a live event starts locally, or simply check what time it is right now in another city, this free time zone calculator gives you a precise answer in seconds. All 39 UTC offsets are supported including fractional-hour zones, the world clock updates live every second, and the swap button makes reverse conversions effortless no sign-up or installation needed.