India, UK and US East Coast team clock

When is everyone in?

The tables below assume a nine-to-six day in each city and count, for every hour of Kolkata's day, how many of the 3 offices are inside theirs. That is an assumption, printed so you can see it — not a recommendation, because nothing here knows anyone's real hours. There is one table per arrangement of the clocks, because 3 different arrangements occur during 2026.

The arrangements, with dates

Kolkata on IST, London on BST, New York on EDT

29 Mar – 25 Oct 2026. Never all 3 at work in a nine-to-six day; at most 2 of 3, at 2:00pm – 6:00pm, 7:00pm – 11:00pm Kolkata time.

Kolkata on IST, London on GMT, New York on EST

1 Jan – 8 Mar 2026; 1 Nov – 31 Dec 2026. Never all 3 at work in a nine-to-six day; at most 2 of 3, at 3:00pm – 6:00pm, 8:00pm – 12:00am Kolkata time.

Kolkata on IST, London on GMT, New York on EDT

8 Mar – 29 Mar 2026; 25 Oct – 1 Nov 2026. Never all 3 at work in a nine-to-six day; at most 2 of 3, at 3:00pm – 6:00pm, 7:00pm – 12:00am Kolkata time.

Shaded cells are inside that city's nine-to-six; a highlighted row has every office in. For a different working day or another city, use the timeline above — the daylight colour on each band is the same question answered by the sun.

Working across Kolkata, London, New York

Most of the world's offshore software delivery runs on this triangle, and the reason it works is not that the three cities overlap — they mostly do not — but that they hand off. India's day ends as London's afternoon begins; London's afternoon overlaps New York's morning; New York's afternoon runs into an empty evening that India picks up the next morning. The tables below show it exactly: there is no hour in a nine-to-six day when all three are at their desks, but there are three or four in which any two are, and they fall at predictable, different times.

The two handoffs are not symmetrical. India to London is comfortable: London's 9am is mid-afternoon in Bengaluru, so an Indian team has its whole morning to itself and then two to three shared hours before it leaves. London to New York is the best transatlantic overlap there is — New York's entire morning inside London's afternoon. India to New York is the hard edge: a New York 9am is 6:30pm or 7:30pm in India depending on the season, so any standing meeting that includes both is somebody's evening, and it is nearly always India's.

Two of the three cities change their clocks, on different dates, so the whole picture shifts four times a year. The United States moves on the second Sunday in March and the first Sunday in November; the United Kingdom on the last Sunday in March and the last Sunday in October. For the two or three weeks each spring and the one week each autumn in between, London and New York are four hours apart instead of five and every India–US meeting moves by an hour while India–UK ones stay put. The table of periods below prints the dates for this year and next, worked out from your browser's own time zone data rather than remembered.

The date line matters more than it looks on this footprint. "End of day Friday" in New York is Saturday morning in India; a Monday 9am standup in India is Sunday evening in New York. Teams that survive this write deadlines with a city attached and use the timeline above to check what that means for the other two before promising anything.

If the footprint is really Pune and Manchester and Boston, nothing changes — all Indian cities share one clock, all of Great Britain shares London's, and the entire US East Coast shares New York's. Toronto too. Add the exact cities in the tool above if it helps the team recognise itself; the bands will be identical.

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
• GOV.UK — When do the clocks change?
• NIST — Daylight Saving Time rules (United States)
• ECMA-402 — the Intl.DateTimeFormat standard these figures are computed with