JST to GMT Converter

Japan Standard Time → Greenwich Mean Time · JST is 9 hours ahead of GMT

JST
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GMT
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JST and GMT are the same time

JST to GMT Conversion Table

JSTGMT
12:00 AM12:00 AM
1:00 AM1:00 AM
2:00 AM2:00 AM
3:00 AM3:00 AM
4:00 AM4:00 AM
5:00 AM5:00 AM
6:00 AM6:00 AM
7:00 AM7:00 AM
8:00 AM8:00 AM
9:00 AM9:00 AM
10:00 AM10:00 AM
11:00 AM11:00 AM
12:00 PM12:00 PM
1:00 PM1:00 PM
2:00 PM2:00 PM
3:00 PM3:00 PM
4:00 PM4:00 PM
5:00 PM5:00 PM
6:00 PM6:00 PM
7:00 PM7:00 PM
8:00 PM8:00 PM
9:00 PM9:00 PM
10:00 PM10:00 PM
11:00 PM11:00 PM

Green rows = business hours overlap (9:00 AM – 6:00 PM JST)

Major JST Cities
  • Tokyo
  • Osaka
  • Kyoto
  • Yokohama
  • Sapporo
  • Fukuoka
Major GMT Cities
  • London
  • Dublin
  • Lisbon
  • Reykjavik
  • Accra
  • Abuja
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JST vs GMT — Tokyo to London

JST (UTC+9) — Japan has no DST, always UTC+9. GMT (UTC+0) — UK winter time. London shifts to BST (UTC+1) from late March to late October.

In UK winter: JST is 9 hours ahead. In UK summer (BST): JST is 8 hours ahead. The Tokyo–London overlap is narrow — Tokyo afternoons (5–9 PM JST) reach London at 8 AM–12 PM GMT.

This corridor matters for finance: Tokyo Stock Exchange (9 AM–3 PM JST) closes before the London Stock Exchange opens (8 AM GMT / 5 PM JST). There is a brief 2-hour overlap when Tokyo is in its afternoon session and London has just opened.

Frequently Asked Questions

How many hours is JST ahead of GMT?

JST (Japan Standard Time, UTC+9) is 9 hours ahead of GMT (UTC+0). Japan does not observe Daylight Saving Time, so this gap is fixed year-round. However, the UK observes BST (UTC+1) in summer (late March–late October), making JST only 8 hours ahead of London time during those months.

What is 9 AM JST in GMT?

9:00 AM JST (Tokyo) is 12:00 AM GMT (midnight) the same day. For scheduling: a 9 AM Tokyo meeting starts at midnight in London (winter/GMT) or 1:00 AM BST (summer). The practical overlap window is very limited — Tokyo afternoon (5:00–8:00 PM JST) = London morning (8:00–11:00 AM GMT).

What is the best time to call London from Tokyo?

The best window to call London (GMT) from Tokyo (JST) in winter is 5:00–9:00 PM JST = 8:00 AM–12:00 PM GMT. In UK summer (BST, UTC+1), Tokyo must call between 6:00–10:00 PM JST to reach London at 9:00 AM–1:00 PM BST. Tokyo afternoons are the only viable overlap window.

Is GMT the same as UTC?

GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) are effectively identical for everyday use — both are UTC+0. The technical difference is that UTC is the international time standard maintained by atomic clocks, while GMT is a time zone used by the UK and West Africa in winter. For time conversion purposes, GMT = UTC.