Time Difference Calculator
Show the math
What Your Result Means
- Time difference: The number of hours between the two zones. A positive value means City 2 is ahead; negative means City 2 is behind. Fractional differences (like +5.5 for India) reflect zones that offset by 30 minutes.
- Current times: The approximate local time right now in each city, based on your device clock and the selected UTC offsets.
- Noon comparison: Shows what time it is in City 2 when it is noon (12:00 PM) in City 1 — a quick way to visualize the overlap for scheduling meetings.
How This Calculator Works
You pick two time zones from the dropdown. The tool subtracts their UTC offsets (stored as fixed numbers) to get the hour difference, then applies those offsets to your browser's current UTC time to show the local clock in each city. Noon comparison simply shifts 12:00 by the difference. It uses standard-time offsets only and does not adjust for daylight saving time.
Quick Questions
Why doesn't this account for daylight saving time?
DST rules vary by country, region, and year — some areas observe it, others do not, and the start/end dates differ. This tool uses fixed standard-time offsets for simplicity. During DST months, the actual difference may shift by one hour. Always double-check near DST transition dates.
Why do some zones have a half-hour offset?
Several countries chose offsets that don't fall on whole hours. India Standard Time (IST) is UTC+5:30, Nepal is UTC+5:45, and parts of Australia use UTC+9:30. These reflect geographic or historical decisions by each nation.
How do I schedule a meeting that works for both cities?
Use the noon comparison as a starting point — it shows what noon in your city looks like in the other. Then adjust to find a window within normal business hours (roughly 9 AM – 6 PM) for both sides. For very large offsets (12+ hours), an early morning or late evening slot for one party is usually unavoidable.
What is the difference between UTC and GMT?
In practice, they represent the same time (UTC+0). UTC is the modern international standard maintained by atomic clocks; GMT is the older astronomical standard tied to the prime meridian at Greenwich. For scheduling purposes, they are interchangeable.
Sources
- Wikipedia — List of UTC Offsets (comprehensive table of all standard UTC offsets by region)
- timeanddate.com — Time Zone Facts (explanations of unusual offsets and DST rules)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.