Time Zone Converter — Convert Time Between Any Two Time Zones
Stop manually calculating time zone differences. The OnlineTimeZone converter uses the browser's native ICU timezone dataset to accurately convert any time between any two of the 400+ IANA time zones. Daylight Saving Time rules for all regions are applied automatically — no need to remember which countries currently observe DST or what their offset is.
Frequently Asked Questions — JST to GMT
Japan Standard Time (JST) is 9 hours ahead of Greenwich Mean Time (GMT). For example, when it is 12:00 PM JST, it is 3:00 AM GMT.
You can convert JST to GMT instantly using our interactive time zone converter above. Simply type your time in the JST field or drag the range slider, and the tool will automatically display the equivalent time in GMT.
The best overlap hours for a meeting are between 5:00 PM and 7:00 PM JST, which corresponds to 8:00 AM to 10:00 AM GMT. This window ensures participants in both locations are awake and within reasonable hours.
Only Greenwich Mean Time (GMT) observes Daylight Saving Time, while Japan Standard Time (JST) remains at a fixed offset all year round. The difference will shift by 1 hour during Daylight Saving transition periods.