KST to JST Converter

Category: Time Zone Converters

- June 20, 2025

| |

Korea Standard Time (KST)

UTC+9 • Seoul, Busan, Incheon, Daegu

Conversion Settings

Configure your timezone conversion preferences

Auto Convert

Daylight Saving Aware

Show UTC Offset

Japan Standard Time (JST)

UTC+9 • Tokyo, Osaka, Yokohama, Nagoya

--:--:--

Select a time to convert

Time Difference: --

UTC Offset (KST): +09:00

UTC Offset (JST): +09:00

DST Status: No DST

KST Time: --

JST Time: --

Time Format:

Current KST: --:--:--

Current JST: --:--:--

🌏 KST and JST are both UTC+9 and never observe daylight saving time. The times are identical between Korea and Japan.

KST to JST Conversion Guide

What is KST to JST Conversion?

KST to JST conversion helps you understand time coordination between Korea Standard Time and Japan Standard Time zones. Both KST and JST are UTC+9 and never observe daylight saving time, making them identical throughout the year. This simplifies business coordination and scheduling between Korea and Japan.

Time Zone Information

Korea Standard Time (KST): Used in both South and North Korea including Seoul, Busan, Incheon, and Daegu. Always UTC+9 with no daylight saving time changes.

Japan Standard Time (JST): Used throughout all of Japan including Tokyo, Osaka, Yokohama, and Nagoya. Always UTC+9 with no daylight saving time changes.

Time Difference: There is no time difference between KST and JST - they are the same time zone.

Daylight Saving Time Impact

No Daylight Saving: Neither Korea nor Japan observes daylight saving time

Year-Round Consistency: KST and JST remain UTC+9 throughout the entire year

Simplified Scheduling: No need to account for seasonal time changes when coordinating between the two countries

Common Conversion Examples

Business Hours

KST 9:00 AM = JST 9:00 AM

KST 5:00 PM = JST 5:00 PM

Identical business hours make coordination simple

Meeting Planning

KST 2:00 PM = JST 2:00 PM

KST 10:00 AM = JST 10:00 AM

No time conversion needed for meetings

Event Scheduling

KST 12:00 PM = JST 12:00 PM

KST 8:00 PM = JST 8:00 PM

Perfect synchronization for regional events

Travel Planning

Seoul 6:00 AM = Tokyo 6:00 AM

Busan 11:30 PM = Osaka 11:30 PM

No jet lag adjustment needed between countries

Conversion Tips & Best Practices

• KST and JST are identical - no time conversion is ever needed

• Both time zones remain UTC+9 throughout the entire year

• Business coordination between Korea and Japan is seamless due to identical time zones

• No daylight saving time complications - consistent year-round scheduling

• Travel between Korea and Japan requires no time adjustment

• Both countries share the same business hours and working schedules effectively

Convert Time Between Korea and Japan

If you’ve ever tried to line up a meeting between Seoul and Tokyo, you probably already know this: the clocks are always in sync. Still, having a clear, no-guesswork tool to check times or document a schedule can save you a step. That’s exactly what this KST↔JST time converter was built for.

What the KST↔JST Converter Actually Does

This tool is a side-by-side time calculator that compares Korea Standard Time (KST) and Japan Standard Time (JST). Since both zones run on UTC+9 year-round with no daylight saving time, the result is always straightforward - but the calculator helps lock that in with date selection, formatting, and live display features.

Whether you’re setting up a cross-border call, syncing with a team in another country, or just making sure your calendar stays tidy, this converter lets you plug in a time from either region and instantly get the matching time on the other side.

How to Use It Without Any Guesswork

Start by Picking a Date and Time

You’ll see a date picker and a time selector under the “Korea Standard Time” section (or “Japan Standard Time,” if you’ve swapped them). Choose any moment you want to convert - past, present, or future.

Choose Which Zone You’re Entering

Below the time inputs is a dropdown to pick whether the time you're entering is in KST or JST. The rest adjusts automatically.

Press Convert or Let It Auto-Update

By default, the “Auto Convert” box is checked, which means the calculator updates in real-time as you type. You can also click the Convert Time button manually if you prefer to control when results show up.

See the Full Breakdown

The results appear under the opposite time zone, with the converted time, matching date, UTC offset (optional), and formatted outputs in both zones.

Need to Flip the Zones?

Click the Swap button to switch your input from KST to JST (or vice versa). The labels and calculations flip accordingly, but your selected time stays put.

Small Features That Make a Big Difference

Live Clocks Right on the Page

At the bottom, you’ll find live time displays for both KST and JST that tick along second by second. Great for a quick glance or reference while you work.

One-Click ‘Now’ Button

Hit the Now button to instantly populate the fields with the current time in your selected input zone. No typing required.

Switch Between 12-Hour and 24-Hour Format

Prefer military time? Want AM/PM? Tap the format button to toggle between 12-hour and 24-hour views. The live clock and converted result both follow suit.

Offset Display Option

If you're working with global schedules or just want to show UTC differences, the “Show UTC Offset” box will add that detail (+09:00) into the results. This is off by default but useful for documentation.

What You Won’t Have to Worry About

No Daylight Saving Adjustments

Neither Korea nor Japan observes daylight saving time, which means there’s no seasonal shifting to deal with. The converter includes a note about this, and the DST checkbox is disabled for clarity.

No Math or Manual Formatting

You don’t need to calculate time differences or reformat anything yourself. The tool takes care of all that. It even displays nicely structured versions of the input and output times - ready for copy-paste into an email, agenda, or chat message.

No Need for Extra Tools

This converter is fully self-contained. No downloads, no plugins, no need to check Google or your phone for backup - everything is visible right there on the page.

Keeping Cross-Border Plans on Time

If you work across Korea and Japan - or just need to confirm something between Seoul and Tokyo - this converter helps you do it without overthinking. No second-guessing the time, no confusion about time zones, and no getting meetings wrong because of seasonal changes. Whether it’s for business, travel, or just staying in sync with someone abroad, this is one of those tools that does exactly what you need it to, every single time.