Time difference from Hyderabad:
London, New York and Dubai

The fixed offsets behind every conversion

Every time zone is a number of hours and minutes ahead of or behind UTC. India Standard Time, used in Hyderabad and throughout the country, is UTC+5:30, a half-hour offset that nearly never changes because India does not use daylight saving time.

London alternates between Greenwich Mean Time (UTC+0) in winter and British Summer Time (UTC+1) in summer. New York uses Eastern Standard Time (UTC−5) in winter and Eastern Daylight Time (UTC−4) in summer. Dubai runs on Gulf Standard Time, UTC+4, with no daylight saving.

Because India holds still, the whole change in the time gap comes from the other side. This is why the difference to Hyderabad varies by exactly one hour for London and New York and not at all for Dubai.

Why India's offset ends in half an hour

India Standard Time is built on the 82.5° east meridian. Earth turns 15 degrees every hour, so 82.5 ÷ 15 = 5.5 hours ahead of UTC, which is where the +5:30 comes from. A single time zone covers the whole country, from Gujarat to Arunachal Pradesh, so Hyderabad's clocks match Delhi's and Chennai's exactly.

That half-hour matters when you convert. London is ahead of or behind UTC by a whole hour, so the gap carries the 30 minutes along. Many people remember 'five and a half' for winter London and forget to subtract an hour in summer.

The arithmetic: subtract the gap

To convert, subtract the gap from the Hyderabad time. If subtraction crosses midnight, the destination date is the previous day. To go the other way, add the gap to the destination time.

Worked example: a call at 8:00 pm Hyderabad time

Now the reverse. A 9:00 am meeting in New York in summer is 9:00 + 9:30 = 18:30 in Hyderabad. In winter the same 9:00 am New York slot is 19:30 IST, so a recurring meeting seems to move an hour twice a year for the India side, even though the New York clock never changed.

Midnight crossings are the trap. A 3:00 am IST start is 17:30 in New York the previous day (3:00 − 9:30 = −6:30, which is 17:30 on the day before), so the date as well as the time needs checking.

A shortcut for London is to remember the winter value, 5:30, and subtract another hour from the gap whenever the UK is on summer time. For New York, start from 10:30 and take away an hour from the second Sunday in March until the first Sunday in November.

When the gaps change in 2026

Daylight saving transitions are governed by local law, so the dates differ between the UK and the US and can be amended. For 2026 they are:

The US starts on the second Sunday of March and ends on the first Sunday of November. The UK and EU start on the last Sunday of March and end on the last Sunday of October. In the weeks between, one side is on summer time and the other is not, so the gaps are different from both the usual summer and usual winter.

• 8–28 March 2026: New York is on EDT but London is still on GMT, so India to New York is 9:30 but India to London is 5:30.
• 25 October – 1 November 2026: London is back on GMT but New York is still on EDT, so the India to London gap is 5:30 while New York stays at 9:30.

Check those windows before scheduling a recurring call. A weekly meeting that was fine in February can land an hour earlier or later for just three weeks.

Finding a slot that works for all four cities

Hyderabad and Dubai are only 1:30 apart, so their working days almost coincide. London sits between them and New York. The comfortable window for a four-way call is narrow: in summer, 9:00 am in New York is 2:00 pm in London, 5:00 pm in Dubai and 6:30 pm in Hyderabad. In winter the same New York 9:00 am is 2:00 pm in London, 6:00 pm in Dubai and 7:30 pm in Hyderabad.

For India and the UK alone, the mid-afternoon IST hours work: 3:00 pm to 6:00 pm IST is 10:30 am to 1:30 pm in London in summer, and 9:30 am to 12:30 pm in winter. For India and New York, evenings in India are the only fair option: 7:00 pm to 10:00 pm IST is 9:30 am to 12:30 pm in New York in summer.

Mistakes that cause missed calls

• Assuming the gap to the US or UK is constant. It differs by an hour between summer and winter.
• Forgetting that India has no DST, and so trusting a rule such as 'India is 5 hours ahead of London' all year.
• Using the wrong abbreviation. EST is winter only; during summer New York is on EDT, and many people write ET for both.
• Ignoring the date when the converted time falls after midnight or before it.
• Not checking the transition weeks in March and in late October, when US and UK clocks are out of step.

A converter does the arithmetic, but it still helps to know the rule behind the number. If a tool returns a gap that surprises you, compare it with the table above before you act on it.