IST to GST time converter

How far apart are Kolkata and Dubai?

Dubai is 1 hour 30 minutes behind Kolkata all year, whether Kolkata is on IST and Dubai on GST. Both cities change their clocks on the same dates, so the gap never moves for more than a few hours at a time — see below.

2026

2027

IST to GST hour table

Every hour of a Kolkata day, read across to Dubai . A row marked +1 day is already tomorrow there; −1 day is still yesterday.

The clock names under each heading are the ones in force at either end of the year. For a half-hour time or a third city, use the timeline above: every clock moves to the instant you pick.

Working across Kolkata and Dubai

Dubai is an hour and a half behind India, and it always is. The United Arab Emirates keeps UTC+4 with no daylight saving and never has had any; India keeps UTC+5:30 and has not changed its clocks since the 1940s. So a 9am start in Dubai is 10:30am in Mumbai, a 9am start in Mumbai is 7:30am in Dubai, and neither of those numbers moves in March or October. The whole Gulf — Abu Dhabi, Muscat — shares Dubai's clock; Riyadh, Doha, Kuwait and Bahrain are an hour further back at UTC+3, so add a Gulf city in the tool above rather than assuming they match.

With such a small, steady gap the clock is not the hard part of working across this pair. The working week is. Since January 2022 the UAE's official week has been Monday to Friday with a half day on Friday, which lines it up with India for the first time — before that it was Sunday to Thursday, and a good deal of the advice still online about "Dubai's weekend" describes the old arrangement. Saudi Arabia and most of the rest of the Gulf still work Sunday to Thursday. The tool above tints Saturdays and Sundays in each city's row; it does not know about Friday half days, so check the invite.

The working-hour overlap is the largest on this site. A nine-to-six day in Dubai runs from 10:30am to 7:30pm in India, so the two offices share seven and a half hours, from 10:30am to 6pm Indian time. Indian teams supporting Gulf customers typically start a little later and finish a little later to cover Dubai's afternoon; Gulf teams rarely need to adjust at all. The cost of this pair shows up in the calendar week rather than the clock: a Thursday-afternoon request from Riyadh lands at the start of a Saudi weekend that India does not share.

GST is the abbreviation the Gulf uses for its own time, and it is not the only thing those letters mean — outside the Middle East GST is often read as a tax, and in tzdata the same offset is simply labelled +04. Nobody in Dubai writes "Gulf Standard Time" on an invite; they write "Dubai time" or "UAE time", which is why those phrases work in the search box above. IST, on the Indian side, is the genuinely ambiguous one, standing also for Israel Standard Time and Irish Standard Time; a Gulf company with Israeli or Irish partners should say "India time" in full.

Because the difference is only ninety minutes the calendar date agrees in both cities except in the last hour and a half before midnight in India, when Dubai is still on the day before. A "midnight IST" release is 10:30pm in Dubai, same date. If the time you are holding is a Unix timestamp, it has no time zone until you give it one — decode it in the epoch converter first, then read it here.

Sources

The offsets, dates and hour tables above are computed when this page is built, from the time zone rules your browser itself ships. The rules come from:

• IANA Time Zone Database — the rules every browser ships
• ECMA-402 — the Intl.DateTimeFormat standard these figures are computed with