UTC Time Converter & World Clock
Convert any date and time to UTC (Zulu) and to major cities around the world, with daylight saving handled for the date you choose. It also gives the ISO 8601 timestamp, Unix time, Julian day and military time zone letter.
Written by Suhaib Hassan. Figures are estimates you can edit. Our methodology.
It uses the browser's IANA time zone database to work out each zone's offset on the exact date, then converts through UTC.
Scheduling across zones goes wrong when daylight saving changes or the date line is crossed. This shows the exact moment in every zone.
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| City | Time | Day |
|---|
Military time zone letters
Each hour of offset from UTC has a letter, said with the NATO phonetic word. Zulu (Z) is UTC. "1430Z" means 14:30 UTC. The letter J is not used, and only whole-hour zones have a letter.
| Letter | Offset from UTC |
|---|---|
| Z Zulu | UTC±0 |
| A Alpha | UTC+1 |
| B Bravo | UTC+2 |
| C Charlie | UTC+3 |
| D Delta | UTC+4 |
| E Echo | UTC+5 |
| F Foxtrot | UTC+6 |
| G Golf | UTC+7 |
| H Hotel | UTC+8 |
| I India | UTC+9 |
| K Kilo | UTC+10 |
| L Lima | UTC+11 |
| M Mike | UTC+12 |
| N November | UTC−1 |
| O Oscar | UTC−2 |
| P Papa | UTC−3 |
| Q Quebec | UTC−4 |
| R Romeo | UTC−5 |
| S Sierra | UTC−6 |
| T Tango | UTC−7 |
| U Uniform | UTC−8 |
| V Victor | UTC−9 |
| W Whiskey | UTC−10 |
| X X-ray | UTC−11 |
| Y Yankee | UTC−12 |
Formulas
How the numbers are worked out.
Convert to UTC
Subtract the zone's offset (including daylight saving on that date) from the local time.
UTC = local time − offsetUnix time and Julian day
Unix time counts seconds from 1 January 1970 UTC. The Julian day counts days from noon on 1 January 4713 BC.
unix = seconds since 1970-01-01T00:00Z
JD = unix ÷ 86,400 + 2,440,587.5Zulu notation
Write the UTC time as four digits and add Z.
14:30 UTC = 1430ZWorked examples
Illustrative figures, each checked by hand. The first is the default setup.
Default
14:30 UTC on 15 May 2026.
New York (EDT, UTC−4): 10:30
Tokyo (JST, UTC+9): 23:30
From New York
9:00 on 15 January 2026 in New York.
Across the date line
23:30 UTC in Tokyo.
How to convert time to UTC
- Enter the date and time, and choose the zone it is in.
- Read the UTC time, Zulu notation, ISO timestamp and Unix time.
- Check the table for the same moment in other cities.
- Use 12-hour or 24-hour display as you prefer.
Time zone rules change. The conversions use your browser's time zone database, so they are as current as your browser. For legal or aviation use, confirm with an official source.
By Suhaib Hassan · Reviewed 29 September 2026 · How CalculatePilot verifies formulas →
Sources
- IANA, Time Zone Database.
- ISO 8601, Date and time format.
- International Civil Aviation Organization and NATO, Time zone letter designators (Z, A to Y).
Frequently asked questions
What is UTC?
Coordinated Universal Time, the world's time standard. It does not change for daylight saving. GMT is the same clock in practice.
What does Zulu mean?
Zulu is the military and aviation name for UTC. The letter Z stands for zero offset, so 1430Z is 14:30 UTC.
Is daylight saving handled?
Yes. Each zone's offset is worked out for the date you enter, so New York is UTC−4 in summer and UTC−5 in winter.
What is Unix time?
The number of seconds since 1 January 1970 at 00:00 UTC. It is the same everywhere.
Why does the day change in some cities?
A time near midnight UTC can already be the next day in zones ahead of UTC, such as Tokyo or Sydney.
How UTC, Zulu time and offsets are converted: UTC time converter guide.
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