JST to GMT Converter

Category: Time Zone Converters

- July 11, 2025

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Japan Standard Time (JST)

UTC+9 • Tokyo, Yokohama, Osaka

Conversion Settings

Configure your timezone conversion preferences

Auto Convert

Show UTC Offset

Show Seconds

Greenwich Mean Time (GMT)

UTC+0 • London, Dublin, Accra

--:--:--

Select a time to convert

Time Difference: --

UTC Offset (JST): +9

UTC Offset (GMT): +0

DST Status: --

JST Time: --

GMT Time: --

Time Format:

Current JST: --:--:--

Current GMT: --:--:--

🌍 JST is UTC+9 and GMT is UTC+0, making JST 9 hours ahead of GMT. Neither timezone observes daylight saving time.

JST to GMT Conversion Guide

What is JST to GMT Conversion?

JST to GMT conversion helps you translate time between Japan Standard Time and Greenwich Mean Time. JST is UTC+9 and GMT is UTC+0, meaning JST is always 9 hours ahead of GMT. Neither timezone observes daylight saving time, making conversion straightforward with a constant 9-hour difference.

Time Zone Information

Japan Standard Time (JST): Used throughout Japan, always UTC+9. Major cities include Tokyo, Yokohama, and Osaka. No daylight saving time observed.

Greenwich Mean Time (GMT): Originally based on mean solar time at Greenwich Observatory, now equivalent to UTC+0. Used in UK during winter and parts of West Africa year-round.

Time Difference: JST is consistently 9 hours ahead of GMT throughout the year.

No Daylight Saving Time Impact

JST Consistency: Japan Standard Time remains UTC+9 throughout the year with no seasonal changes

GMT Consistency: Greenwich Mean Time remains UTC+0 throughout the year (note: UK uses BST in summer)

Constant Difference: The 9-hour difference remains fixed permanently between these timezones

Common Conversion Examples

Business Hours

JST 9:00 AM → GMT 12:00 AM

JST 5:00 PM → GMT 8:00 AM

Standard business day conversion

International Meetings

JST 10:00 AM → GMT 1:00 AM

JST 8:00 PM → GMT 11:00 AM

Global coordination challenges

Financial Markets

JST 9:00 AM → GMT 12:00 AM

JST 3:00 PM → GMT 6:00 AM

Tokyo market opening times

Travel & Events

JST 11:00 PM → GMT 2:00 PM

JST 1:00 AM → GMT 4:00 PM (previous day)

Cross-date boundary examples

Conversion Tips & Best Practices

• Subtract 9 hours from JST to get GMT time

• Both timezones are permanently fixed with no seasonal adjustments

• GMT dates often change when converting from late JST times

• Business hours rarely overlap between Japan and GMT regions

• GMT is the historical reference for world timekeeping

• Note that UK uses BST (GMT+1) during summer months, not GMT

Convert Time Between JST and GMT

If you're trying to juggle meetings between Japan and countries that run on GMT, this tool saves you the headache. Below, you’ll find a handy table showing which countries are in each timezone. Whether you're coordinating with a client in Tokyo or syncing a project with a team in Ghana, this will help you get everyone on the same page quickly.

Japan Standard Time (UTC+9)	Greenwich Mean Time (UTC+0)
🇯🇵 Japan 🇰🇷 South Korea 🇵🇼 Palau 🇮🇩 Indonesia (parts of eastern Indonesia including Papua, WEST Papua) 🇹🇱 Timor-Leste 🇷🇺 Russia (Yakutsk, Chita) 🇲🇭 Marshall Islands (Kwajalein and others) 🇲🇳 Mongolia (eastern provinces)	🇬🇧 United Kingdom (in winter, not during BST) 🇮🇪 Ireland (in winter) 🇬🇭 Ghana 🇨🇮 Côte d'Ivoire 🇹🇬 Togo 🇸🇱 Sierra Leone 🇬🇲 The Gambia 🇸🇳 Senegal 🇬🇳 Guinea 🇧🇫 Burkina Faso 🇱🇷 Liberia 🇲🇷 Mauritania 🇲🇱 Mali 🇸🇭 Saint Helena, Ascension and Tristan da Cunha

Built to Make Time Zones Less of a Puzzle

The JST to GMT converter is designed for anyone who works or communicates across Japan and GMT-based regions. It simplifies time coordination by giving you instant conversions between Japan Standard Time (UTC+9) and Greenwich Mean Time (UTC+0). You can set a specific date and time, swap directions, show seconds, toggle between 12 and 24-hour clocks, and even show or hide the UTC offset.

Why You Might Use This Calculator

If you're scheduling calls between Tokyo and London, managing a team that spans Seoul to Accra, or just want to track market openings across continents, this tool cuts the guesswork. No need to do mental math or search for world clocks. This converter handles the 9-hour difference instantly and clearly.

How It Works: A Step-by-Step Guide

1. Choose the Date and Time

Use the calendar and time input fields to set the exact moment you want to convert. You can select either JST or GMT as your input timezone using the dropdown.

2. Use the Convert Button or Auto Mode

If auto-convert is checked (it is by default), the conversion happens as soon as you change the date or time. If not, just click the big Convert Time button to trigger it.

3. Check the Result

The converted time will show clearly with seconds and date, if enabled. You’ll also see extra details like the UTC offset, DST status (both JST and GMT don’t use DST), and the formatted time in both time zones.

4. Optional: Use the Extra Controls

Swap: Instantly flip the direction of conversion between JST and GMT.
Now: Pulls the current time based on the input timezone and converts it on the spot.
Reset: Brings everything back to the default state using current JST time.
12/24 Hour Format: Toggle between time displays that match your preference.

Useful Add-ons That Work Quietly Behind the Scenes

The converter includes live clocks showing the current time in both JST and GMT. It updates every second, so even if you're not actively converting, you can see how far apart the regions are at any given moment. There's also a detailed summary that outlines the time difference (always 9 hours), making the whole process easy to follow even if you're not a time-zone expert.

Where This Tool Comes in Handy

Let’s say you're planning a webinar from Tokyo and want folks in West Africa to join live. You set the JST time to 7:00 PM, hit convert, and get the exact corresponding GMT time of 10:00 AM. That helps you publish your event globally without confusion. This comes in especially useful for coordinating events between countries like 🇯🇵 Japan and 🇬🇭 Ghana, or 🇰🇷 South Korea and 🇬🇧 the United Kingdom (in winter months).

Keep Your International Meetings on Point, Every Time

This tool takes a process that usually eats up time and energy and makes it simple. Whether you’re hosting calls, planning travel, or running a global team, having an accurate JST to GMT converter at your fingertips helps you move faster and avoid misunderstandings. It’s like having a timezone-savvy assistant, ready whenever you need it.