JST to IST Converter

The Torii-Gate Offset Dial

Common Tokyo Times

One-click presets for office hours, market opens, and family-call windows.

JST → IST Conversion Table

Need the reverse direction? Try the CET to IST converter or browse all Time & Date tools.

The Conversion Formula

Reference: JST & IST Facts

No saved conversions yet. Tap "Save to History" to remember up to six Tokyo–India mappings.

How to Convert JST to IST

1. Enter the Tokyo time (JST) in the time field beside the torii-gate dial, or tap a preset like "Tokyo 9:00 AM".
2. Read the India clock on the right of the dial — it automatically shows the time 3 hours 30 minutes earlier.
3. Check the day-rollover flag under the bullet train. If the India time crossed midnight, it shows "previous day" or "next day".
4. Use "Use my current time as JST" to map this very moment from Tokyo to India, handy during a live call.
5. Tap "Save to History" to keep up to six conversions for comparison; clear them anytime.

Why a Tokyo–India Time Converter Exists

In 2026, a product manager in Bengaluru coordinating a release with a partner team in Tokyo opens a calendar at 9:00 AM Japan Standard Time and needs to know, without arithmetic mistakes, that her counterparts in India are at 5:30 AM — still asleep. JST to IST exists for exactly that friction: India Standard Time runs precisely 3 hours and 30 minutes behind Japan Standard Time, every single day of the year, because neither country observes daylight saving time. This calculator turns that fixed −3:30 offset into a live torii-gate dial linking a Tokyo clock to an India clock.

Japan Standard Time (JST) is UTC+9, fixed by the Meiji government in 1888 when Japan adopted the 135° east meridian running through Akashi, near Kobe, as its national standard. Japan briefly experimented with daylight saving time under the Allied occupation between 1948 and 1951, but abandoned it; since 1951 JST has been a single, year-round offset with no summer shift. That permanence is why a Tokyo-to-India conversion never needs an asterisk for the season.

India Standard Time (IST) is UTC+5:30, anchored to the 82.5° east meridian that passes through Mirzapur in Uttar Pradesh, near Allahabad (Prayagraj). India adopted a single national time zone in 1906 and formalised IST at independence in 1947. The half-hour offset — shared with Sri Lanka and, in 45-minute form, with Nepal — is what makes the JST-to-IST gap an unusual 3 hours and 30 minutes rather than a round number, a detail that trips up anyone doing the mental math in whole hours.

The 3.5-hour gap shapes the working overlap between the two countries. When Tokyo opens at 9:00 AM, India is at 5:30 AM; when Tokyo closes at 6:00 PM, India is at 2:30 PM. The practical sweet spot for a live call is the Tokyo afternoon — 2:00 PM to 6:00 PM JST maps to 10:30 AM to 2:30 PM IST, comfortably inside India's morning. Indian IT services firms such as TCS, Infosys, and Wipro, all of which run large Japan-facing delivery centres, build their shift rosters around precisely this window.

The offset also matters for finance. The Tokyo Stock Exchange opens at 9:00 AM JST (5:30 AM IST) and the Nikkei 225's morning session is well underway before the National Stock Exchange of India even rings its 9:15 AM IST bell. Traders watching both markets keep a JST-to-IST converter open so the −3:30 shift never costs them a fill. The bullet-train metaphor on this page is deliberate: the Tōkaidō Shinkansen, which opened for the 1964 Tokyo Olympics, runs on a timetable so precise that average delays are measured in seconds — a fitting symbol for a fixed, never-drifting time offset.

Because both JST and IST are DST-free, this converter is one of the few timezone tools that needs no seasonal logic at all. Whether you are scheduling a December video call or an August one, Tokyo stays exactly 3 hours and 30 minutes ahead of Mumbai, Delhi, Bengaluru, Chennai, Hyderabad, and Kolkata. The only thing that ever changes is the date rollover: a late-night Tokyo time can land on the previous calendar day in India. The dial above flags that crossing whenever it happens.