Time Zone Converter
Show the math
What Your Result Means
- Converted time: The equivalent clock time in the target time zone. If you entered 3:00 PM EST and converted to JST (UTC+9), you would see the corresponding Japan time.
- Time difference: The offset between source and target zones, shown as hours and minutes. This tells you how far apart the two zones are from each other.
- Date change: Indicates whether the conversion crosses midnight — "Next day (+1)" means the target time falls on the following calendar day, "Previous day (−1)" means it falls on the day before.
How This Calculator Works
You enter a clock time and select source and target time zones. The tool looks up each zone's standard UTC offset, computes the difference, then adds that difference to the input hours. If the result exceeds 24 or drops below 0, it wraps to the next or previous day. It uses fixed standard-time offsets and does not apply daylight saving adjustments.
Quick Questions
Does this handle daylight saving time?
No. This converter uses standard UTC offsets year-round. During daylight saving periods, many regions shift by one hour, so the actual conversion may be off by an hour. Check near DST transition dates (typically March and November in North America).
Why does converting to IST show a 30-minute offset?
India Standard Time is UTC+5:30, one of several zones that use a half-hour offset. The calculator handles fractional hours correctly. Nepal (UTC+5:45) and the Chatham Islands (UTC+12:45) are other examples of non-whole-hour offsets.
What does "Next day" or "Previous day" mean?
If adding the time-zone difference pushes the clock past midnight (24:00) or before midnight (0:00), the date changes. "Next day" means the converted time is on the following calendar day; "Previous day" means it falls on the day before your source date.
Is UTC the same as GMT?
For practical purposes, yes — both represent the time at the prime meridian with zero offset. UTC is the modern standard maintained by atomic clocks, while GMT is the older astronomical term. This tool treats them identically (UTC+0).
Sources
- Wikipedia — List of UTC Offsets (comprehensive reference of standard time zone offsets)
- Wikipedia — Coordinated Universal Time (definition and history of the UTC standard)
- timeanddate.com — Time Zone Map (visual map of world time zones with DST information)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.