Convert EST to JST
To convert EST to JST: 10:00 AM EST is 12:00 AM JST the next day. EST is UTC-05:00 and JST is UTC+09:00, so JST is 14 hours ahead of EST, but not all year, as explained below.
In Japan Standard Time
- 10:00 AM EST
- 12:00 AM JST (next day)
- On a 24-hour clock
- 10:00 EST is 00:00 JST
- The offsets
- EST is UTC-05:00, JST is UTC+09:00
- Difference
- JST is 14 hours ahead of EST
- Date
- The next day. Adding 14 hours crosses midnight from this time.
- This gap does NOT hold all year Convert through the offset in force on the date you care about.
- The two ends switch on different dates, or one does not switch at all.
- EST is only in force part of the year United States: daylight time starts the second Sunday in March, at 02:00 local time and ends the first Sunday in November, at 02:00 local time (Energy Policy Act of 2005, in force since 2007). In 2026 that is 2026-03-08 to 2026-11-01. New York is on EDT between those dates.
- otherwise EDT, UTC-04:00
- Military time zone letters Z (Zulu) is UTC. A to M run east of Greenwich an hour apart, N to Y west, and J is left out. A letter names an offset, so a zone that switches to daylight time changes letter: EST is R, EDT is Q.
- EST is R (Romeo), JST is I (India)
- In every zone
- HST 05:00 AKST 06:00 PST 07:00 AKDT 07:00 MST 08:00 PDT 08:00 CST 09:00 MDT 09:00 EST 10:00 CDT 10:00 EDT 11:00 UTC 15:00 GMT 15:00 BST 16:00 CET 16:00 CEST 17:00 EET 17:00 EEST 18:00 MSK 18:00 IST 20:30 SGT 23:00 HKT 23:00 JST 00:00 AEST 01:00 AEDT 02:00 NZST 03:00 NZDT 04:00
How the Time Zone Converter works
Eastern Standard Time (EST) is UTC-05:00 and Japan Standard Time (JST) is UTC+09:00, so converting EST to JST means adding 14 hours to the EST time. JST is 14 hours ahead of EST.
Worked through: 10:00 AM EST is 12:00 AM JST the next day. Note the date: this pair crosses midnight for much of the day, so the answer is often a different day as well as a different time. The day is the part a conversion done in your head tends to drop.
The gap between these two is not the same all year, which is the thing to get right. JST never shifts and EST does, so the difference moves. Convert through the offset in force on the date you care about rather than through the abbreviation somebody typed; the offsets above are definitions and the abbreviation is a claim about the calendar.
Thirteen or fourteen hours forward, and the direction where the next-day answer is the normal case rather than the edge case: anything after 10:00 Eastern is tomorrow in Tokyo. The useful anchor is that 20:00 in New York is 10:00 the following morning in Tokyo. That is the one slot where a US evening meets a Japanese morning, and it is when most US-Japan calls get scheduled.
One thing worth stating plainly, because it is the most common mistake in this whole subject: an abbreviation is not a place. EST is Eastern Standard Time, which New York uses only part of the year; the rest of the time it is on EDT at UTC-04:00. JST does not shift. If what you have is a city and a date rather than a pair of abbreviations, that is a different question and needs the tz database, not arithmetic. This is also why the shifting designations exist: ET means Eastern time whichever of the two is in force. Searching for ET and searching for EST to JST are the same question in two vocabularies, which is why this converter answers both.
Common times for this pair:
- 8:00 AM EST is 10:00 PM JST - 10:00 AM EST is 12:00 AM JST the next day - 7:00 PM EST is 9:00 AM JST the next day - 8:00 PM EST is 10:00 AM JST the next day
Time Zone Converter FAQ
What is the time difference between EST and JST?
JST is 14 hours ahead of EST. EST is UTC-05:00 and JST is UTC+09:00, and both offsets are definitions rather than measurements, so the subtraction is exact.
What time is 10:00 AM EST in JST?
10:00 AM EST is 12:00 AM JST the next day. Add 14 hours and carry the date if it crosses midnight.
Does the difference between EST and JST change with daylight saving?
Yes, and this is the main thing to watch on this pair. JST is fixed and EST shifts by an hour for part of the year, so the difference takes more than one value across the year. In 2026 the United States switch runs from 2026-03-08 to 2026-11-01.
Is there anything specific to this pair worth knowing?
Thirteen or fourteen hours forward, and the direction where the next-day answer is the normal case rather than the edge case: anything after 10:00 Eastern is tomorrow in Tokyo. The useful anchor is that 20:00 in New York is 10:00 the following morning in Tokyo. That is the one slot where a US evening meets a Japanese morning, and it is when most US-Japan calls get scheduled.
Someone wrote EST but it is summer. What do they mean?
Almost certainly the zone rather than the abbreviation: New York time, which in summer is EDT at UTC-04:00 rather than EST at UTC-05:00. People type the standard-time abbreviation all year round. If an invitation is an hour out from what you calculated, this is why.