UTC to JST Time Converter (UTC / Greenwich to Tokyo)
Convert UTC (Coordinated Universal Time, UTC / Greenwich) to JST (Japan Standard Time, Tokyo) instantly. View live clocks, 24-hour comparison table, best meeting overlap hours, and developer code snippets.
Interactive Hour Converter (UTC → JST)
Drag slider to test any hour24-Hour UTC to JST Time Conversion Table
Side-by-side hourly reference with business hours overlap indicators.
| UTC (UTC / Greenwich) | 24h | JST (Tokyo) | 24h | Status in JST |
|---|---|---|---|---|
| 12:00 AM | 00:00 | 9:00 AM | 09:00 | Work Hours |
| 1:00 AM | 01:00 | 10:00 AM | 10:00 | Work Hours |
| 2:00 AM | 02:00 | 11:00 AM | 11:00 | Work Hours |
| 3:00 AM | 03:00 | 12:00 PM | 12:00 | Work Hours |
| 4:00 AM | 04:00 | 1:00 PM | 13:00 | Work Hours |
| 5:00 AM | 05:00 | 2:00 PM | 14:00 | Work Hours |
| 6:00 AM | 06:00 | 3:00 PM | 15:00 | Work Hours |
| 7:00 AM | 07:00 | 4:00 PM | 16:00 | Work Hours |
| 8:00 AM | 08:00 | 5:00 PM | 17:00 | Work Hours |
| 9:00 AM | 09:00 | 6:00 PM | 18:00 | Awake / Flex |
| 10:00 AM | 10:00 | 7:00 PM | 19:00 | Awake / Flex |
| 11:00 AM | 11:00 | 8:00 PM | 20:00 | Awake / Flex |
| 12:00 PM | 12:00 | 9:00 PM | 21:00 | Awake / Flex |
| 1:00 PM | 13:00 | 10:00 PM | 22:00 | Awake / Flex |
| 2:00 PM | 14:00 | 11:00 PM | 23:00 | Sleeping |
| 3:00 PM | 15:00 | 12:00 AM | 00:00 | Sleeping |
| 4:00 PM | 16:00 | 1:00 AM | 01:00 | Sleeping |
| 5:00 PM | 17:00 | 2:00 AM | 02:00 | Sleeping |
| 6:00 PM | 18:00 | 3:00 AM | 03:00 | Sleeping |
| 7:00 PM | 19:00 | 4:00 AM | 04:00 | Sleeping |
| 8:00 PM | 20:00 | 5:00 AM | 05:00 | Sleeping |
| 9:00 PM | 21:00 | 6:00 AM | 06:00 | Sleeping |
| 10:00 PM | 22:00 | 7:00 AM | 07:00 | Awake / Flex |
| 11:00 PM | 23:00 | 8:00 AM | 08:00 | Awake / Flex |
Developer Code Snippets (UTC to JST)
// Convert current time from UTC (UTC) to JST (Asia/Tokyo)
const now = new Date();
const inJST = new Intl.DateTimeFormat('en-US', {
timeZone: 'Asia/Tokyo',
dateStyle: 'medium',
timeStyle: 'long'
}).format(now);
console.log(inJST);# Python 3.9+ using standard zoneinfo
from datetime import datetime
from zoneinfo import ZoneInfo
dt_utc = datetime.now(ZoneInfo("UTC"))
dt_jst = dt_utc.astimezone(ZoneInfo("Asia/Tokyo"))
print(f"UTC: {dt_utc.strftime('%Y-%m-%d %H:%M %Z')}")
print(f"JST: {dt_jst.strftime('%Y-%m-%d %H:%M %Z')}")Frequently Asked Questions (UTC → JST)
How do I convert UTC to JST?
UTC (Coordinated Universal Time) uses the IANA timezone identifier UTC (standard offset +00:00), while JST (Japan Standard Time) uses Asia/Tokyo (standard offset +09:00). Use the interactive slider or the 24-hour table above to convert any hour accurately with automatic Daylight Saving Time (DST) adjustment.
What are the best meeting hours between UTC / Greenwich and Tokyo?
Check the rows highlighted with "Best Meeting Overlap" in the 24-hour table above, where both UTC and JST fall within standard 9:00 AM – 5:00 PM working hours.
Does UTC to JST account for Daylight Saving Time (DST)?
Yes. Castov uses the browser's native IANA tzdb engine (UTC and Asia/Tokyo), which automatically applies official Daylight Saving Time transitions.