World Clock Time Difference Calculator
Compare times between two world time zones
Enter two time zones and a reference time. Get the matching time in the other zone and the exact offset difference for that moment.
World clock time difference calculator for scheduling across time zones
This calculator is for one specific job: you have a time in one place and you need to know what time it is in another place, at that same moment. That is the real-world pain behind most searches for “time difference between cities,” “what time is it in X when it’s Y in Z,” and “convert meeting time across time zones.”
The input is simple. You enter a “From” time zone, a “To” time zone, and (optionally) a date and time as written in the From zone. If you leave the date and time blank, the calculator uses the current moment and tells you what time it is right now in the other zone and the current offset difference. If you enter a date and time, it converts that scheduled time instead, which is the only reliable way to plan meetings around daylight saving changes.
The results are designed for decisions, not trivia. You get the matching time in the To zone, the exact time difference in hours and minutes for that moment, and the UTC offsets for both zones. You also get a day-shift hint (same day, next day, or previous day) so you do not accidentally schedule something on the wrong date when the zones are far apart.
Assumptions and how to use this calculator
- Time zones must be valid IANA names (for example Africa/Johannesburg or America/New_York). Abbreviations like “EST” can be ambiguous and may fail.
- If you leave the date and time blank, the calculator uses your current moment and converts it between zones.
- If you enter a date and time, it must be in the From zone (not your device’s zone), formatted as YYYY-MM-DD HH:MM using 24-hour time.
- Daylight saving time is handled automatically based on the official rules in each zone for that date.
- If a chosen wall time is “skipped” or “repeated” during a DST change, the calculator applies the most practical interpretation by resolving to the nearest valid instant.
Common questions
Why do I need a date, not just a city-to-city time difference?
Because the difference between two places can change during the year when daylight saving rules start or end. A fixed “X hours ahead” statement can be wrong for scheduled meetings. Using a date and time gives the correct offset for that specific moment.
What should I type for the time zone?
Use an IANA time zone name. It looks like Region/City, such as Europe/London, Asia/Dubai, or America/Los_Angeles. If you are not sure, search your device settings for “time zone” and use the name shown there.
What if I only know the city name?
This calculator does not guess cities. City names are not standardized and many cities share the same offset but different daylight saving rules. Use a known IANA time zone instead. If you are planning travel, your airline or hotel confirmations often include the correct time zone for the location.
Why does it say “next day” or “previous day”?
When zones are far apart, converting a time can cross midnight. The day-shift note is there to prevent common scheduling errors, like booking a call for Monday in one zone that is already Tuesday in the other zone.
Why did my input time fail validation?
The calculator expects a strict format: YYYY-MM-DD HH:MM using 24-hour time (for example 2025-12-22 14:30). If you prefer, leave it blank and use “now,” then adjust your meeting time externally. The strict format avoids silent parsing mistakes that lead to incorrect scheduling.