What is the time difference between JST and GMT?

Greenwich Mean Time (GMT) is 8 hours behind Japan Standard Time (JST). JST uses a UTC offset of UTC+9, while GMT uses UTC+1. For example, when it's 9:00 AM in JST, it's 1:00 AM in GMT. Note that this difference may shift by one hour during daylight saving time transitions if GMT observes DST. Use the conversion table above to see the exact time for each hour of the day.

How do I convert JST to GMT?

To convert JST to GMT, subtract 8 hours from the JST time. For example, 9:00 AM JST is 1:00 AM GMT, and 5:00 PM JST is 9:00 AM GMT. Keep in mind that during daylight saving time transitions, the offset between these timezones may temporarily change by one hour. You can also use the interactive converter above for quick, accurate results.

What time is it in GMT when it's noon in JST?

When it's 12:00 PM (noon) in JST, it's 4:00 AM in GMT. This is because GMT is 8 hours behind JST. Similarly, when it's 6:00 PM in JST, it's 10:00 AM in GMT. During daylight saving time transitions, these times may shift by one hour, so always verify the current offset. The color-coded conversion table above shows every hour mapped between both timezones.

How many hours behind is GMT from JST?

GMT is 8 hours behind JST. This means when it's 9:00 AM in JST, it's 1:00 AM in GMT, and when it's midnight in JST, it's 4:00 PM in GMT. The exact difference can vary by one hour during daylight saving time transitions. The conversion table above provides a complete hour-by-hour mapping.

Is GMT ahead or behind JST?

GMT is behind JST by 8 hours. Clocks in GMT show an earlier time than JST, meaning the day starts later in GMT relative to JST. For example, when it's noon in JST, it's still 4:00 AM in GMT. This gap may change by one hour during DST transitions.

Does JST observe daylight saving time?

No, Japan Standard Time does not observe daylight saving time. The UTC offset of UTC+9 remains the same year-round, making time conversions from JST more predictable. Countries and regions in this timezone keep their clocks unchanged regardless of the season.

Does GMT observe daylight saving time?

Yes, Greenwich Mean Time observes daylight saving time. During DST, the abbreviation changes to BST and clocks move forward by one hour, typically in spring. Clocks then fall back in autumn, returning to standard GMT time. This means the UTC offset for GMT shifts between two values depending on the season. Check our DST change calendar for exact transition dates that may affect your JST to GMT conversions.

What is the best time to call from JST to GMT?

The best time for a call between JST and GMT is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in GMT during their work day, call between 5:00 PM and 1:00 AM your JST time. Avoid calling too early or late, as the 8 hours difference means your evening could be their early morning. Check the color-coded conversion table above — green hours indicate business hours in both zones, making it easy to find the ideal time.

When does daylight saving time change in GMT?

Daylight saving time transitions vary by year and region. Greenwich Mean Time observes DST, which typically shifts clocks forward by one hour in spring ("spring forward") and back in fall ("fall back"). During these transition periods, the time difference between JST and GMT may temporarily change by one hour, which can cause confusion for scheduled meetings or calls. It's important to double-check your conversions around transition dates, especially if the two timezones switch on different dates. Check our DST change calendar for exact transition dates in the current year.

Do JST and GMT ever have the same time?

No, JST and GMT never show the same time because their base UTC offsets are different. However, because GMT observes daylight saving time and JST does not, the time difference between them changes by one hour during DST transitions. This means the gap narrows or widens depending on the season, but the two clocks never align. Always verify the current offset around DST transition dates to avoid scheduling errors.

JST to GMT Converter

Convert Japan Standard Time to Greenwich Mean Time. See the hour-by-hour conversion table below.

Timezone Details

Japan Standard Time

3:53 PM

Saturday, April 4, 2026

JST (UTC+09:00)

Greenwich Mean Time

7:53 AM

Saturday, April 4, 2026

BST (UTC+01:00)

Difference: -8 hours

JST DST: No

BST DST: Yes (BST)

24-Hour Overview

JST — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

BST — 24-hour overview

4p4p

7p7p

10p10p

11p

12a

1a1a

4a4a

7a7a

10a10a

11a

12p

1p1p

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

GMT to JST EST to GMT GMT to EST EST to JST JST to EST PST to GMT GMT to PST PST to JST JST to PST

Cities in These Timezones

JST Cities

Tokyo Osaka Fukuoka

GMT Cities

London Manchester Edinburgh

More Tools

Compare JST & GMT Plan a Meeting (JST & GMT)See on Map

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

Japan Standard Time on Wikipedia Greenwich Mean Time on Wikipedia IANA Time Zone Database