KST to JST Time Converter
Use this KST to JST time converter to compare South Korea and Japan time instantly. JST is 0 hours equal to KST, so 9:00 AM KST becomes 9:00 AM JST and 5:00 PM KST becomes 5:00 PM JST. The page is useful for business-hours overlap, international calls, remote-team handoffs, webinars, and travel planning, with daylight saving adjustments handled automatically.
KST to JST Quick Facts
Use this KST to JST converter to compare South Korea and Japan time, check the 0 hours gap, and confirm the right slot for calls, handoffs, and deadlines. Good overlap starts around 9:00 AM KST / 9:00 AM JST.
How to Convert KST to JST
Converting between Korea Standard Time and Japan Standard Time means no offset adjustment — here's how to do it in under 10 seconds with no sign-up.
Pick the date and time in Korea Standard Time (UTC +9) that you want to convert. Hit "Now" to load the current KST time instantly, or use "+1h" to step forward and compare.
The equivalent Japan Standard Time (UTC +9) time appears immediately. Since JST is 0 hours behind of KST, most daytime conversions stay on the same calendar day.
Click "Copy Time" to grab the JST result for your calendar or message. Use "+1d" to check how the conversion shifts across dates — useful when Daylight Saving Time changes the gap.
Why Choose Our KST to JST Converter
When someone in South Korea suggests 9:00 AM KST, that's 9:00 AM JST. This converter shows the overlap so both sides agree on one slot — no back-and-forth.
Late-night KST times can land on a different date in JST because of the 0 hours offset. The converter labels "next day" or "previous day" next to the result so you never send a message a day early or miss a deadline.
Daylight Saving adjustments can widen or narrow the KST–JST gap by an hour. During transition weeks many people get it wrong. This converter pulls the current UTC offsets automatically, so the result is right even on the changeover day.
Product launches, sports matches, and webinars are often announced in KST. Convert the event time to JST so you know exactly when to tune in — since both zones share the same offset, no conversion is needed but this tool confirms it instantly.
KST to JST Time Conversion Chart
Quick-reference conversion table covering every hour of the day at a glance.
Korea Standard Time to Japan Standard Time full day schedule
| Korea Standard Time | Japan Standard Time |
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| 12:00 AM |
12:00 AM
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| 1:00 AM |
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| 2:00 AM |
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| 3:00 AM |
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| 4:00 AM |
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| 5:00 AM |
5:00 AM
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| 6:00 AM |
6:00 AM
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| 7:00 AM |
7:00 AM
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| 8:00 AM |
8:00 AM
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| 9:00 AM |
9:00 AM
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| 10:00 AM |
10:00 AM
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| 11:00 AM |
11:00 AM
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| 12:00 PM |
12:00 PM
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| 1:00 PM |
1:00 PM
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| 2:00 PM |
2:00 PM
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| 3:00 PM |
3:00 PM
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| 4:00 PM |
4:00 PM
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| 5:00 PM |
5:00 PM
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| 6:00 PM |
6:00 PM
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| 7:00 PM |
7:00 PM
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| 8:00 PM |
8:00 PM
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| 9:00 PM |
9:00 PM
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| 10:00 PM |
10:00 PM
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| 11:00 PM |
11:00 PM
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Timezone offsets and DST rules verified against the IANA Time Zone Database. Conversion math and business-hour overlap windows double-checked against real-world scheduling scenarios.
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KST to JST FAQ
Quick answers about daylight saving time, date changes, business-hour overlap, and the most common scheduling questions between Korea Standard Time and Japan Standard Time.
What is the time difference between KST and JST?
When can KST and JST have business-hour overlap?
Does KST or JST observe daylight saving time?
How do I quickly convert KST to JST?
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