Zone-to-Zone Converters
These pages answer "what time is it there?" for one corridor at a time — and, just as important, explain when the answer changes. Every number on them is computed for the exact date from the IANA time zone database; the figures on this index are as of September 2026.
Why abbreviations need a page each
Three letters are a poor name for a time zone, for two reasons. The first is ambiguity. On this site IST means India Standard Time, but the same letters also mean Irish Standard Time and Israel Standard Time. CST here is Central Standard Time (North America); the letters also mean China Standard Time and Cuba Standard Time. And GMT is usually typed to mean London time, even though London does not keep GMT all year — it moves to BST (British Summer Time) while daylight saving is active. The letters are also used for UTC±0 kept year-round, which London does not do.
Second, an abbreviation does not encode daylight-saving rules. A zone that observes daylight saving has two of them — EST/EDT, CST/CDT, MST/MDT, PST/PDT, GMT/BST, CET/CEST, and AEST/AEDT — and people write the standard one all year regardless of which is in force. So "EST" in the everyday sense means New York time, whichever of EST or EDT the clocks are currently showing. A converter that took "EST" literally would be wrong for the whole of the daylight-saving season.
That is why each corridor gets a page of its own. Every page states the exact IANA zone behind
each abbreviation — IST is Asia/Kolkata, EST is
America/New_York, GMT is Europe/London — so you can check it is the meaning
you had in mind, and the converter applies that zone's real rules to the date you enter.
Four kinds of corridor
What makes a pair interesting is whether the gap between its two zones is one number or several. The engine behind these pages scans a full year ahead from the build date, samples the real offset of both zones day by day, and bisects every change down to the minute. From that scan it sorts each corridor into one of four regimes.
Fixed. Neither side shifts its clocks — or, in a degenerate case, the shifts cancel exactly — so the gap is one number all year. There is nothing to watch.
One side shifts. Exactly one of the two zones observes daylight saving. The gap therefore takes two values a year, and it moves on that zone's transition dates — dates chosen by the shifting side, not the one that stays put. If you live on the fixed side, the change arrives on someone else's calendar and is easy to miss.
Both shift together. Both zones observe daylight saving and switch on the same dates, so the two shifts cancel and the gap never moves. As of September 2026, PST to EST, CST to EST, MST to EST, and CET to GMT below are examples.
Both shift on different dates. Both zones observe daylight saving, but under different calendars. When both sides shift in the same half of the year, the shifts cancel for most of it. But between one side's switch and the other's, the gap holds a value it holds only inside these mismatch windows. These windows are short — the engine reports the briefest one for each such pair — and they are the ones that break recurring meetings: a weekly call that has been right for months is suddenly out by one full clock change for the length of the mismatch window, then quietly right again.
The extreme case is a pair split across the hemispheres, where daylight saving runs in opposite halves of the year: one side springs forward while the other falls back. As of September 2026, AEST to EST is in that position, and the gap takes 3 distinct values across the year rather than two.
Not every gap is a whole number of hours, either. As of September 2026, EST is 9:30 hours behind IST, PST is 12:30 hours behind IST, and GMT is 4:30 hours behind IST. Each converter carries the minutes through, so a half-hour or 45-minute zone is never rounded away.
The corridors
16 corridors, grouped by regime. The gap shown is the value in force as of September 2026; where it varies, the range across the year ahead is given too. Follow a link for the live converter, the exact instants at which the gap moves, and the working-hours overlap for that pair.
Fixed gap (0)
No corridor on this list is classified this way as of September 2026.
One side shifts (8)
- IST to EST India and the US East Coast. As of September 2026, EST is 9:30 hours behind IST. Changes between 10:30 hours behind and 9:30 hours behind; the EST side is the one that shifts.
- IST to PST India and the US West Coast. As of September 2026, PST is 12:30 hours behind IST. Changes between 13:30 hours behind and 12:30 hours behind; the PST side is the one that shifts.
- IST to GMT India and the United Kingdom. As of September 2026, GMT is 4:30 hours behind IST. Changes between 5:30 hours behind and 4:30 hours behind; the GMT side is the one that shifts.
- UTC to EST Server time and the US East Coast. As of September 2026, EST is 4 hours behind UTC. Changes between 5 hours behind and 4 hours behind; the EST side is the one that shifts.
- JST to EST Tokyo and New York. As of September 2026, EST is 13 hours behind JST. Changes between 14 hours behind and 13 hours behind; the EST side is the one that shifts.
- PHT to PST Manila and the US West Coast. As of September 2026, PST is 15 hours behind PHT. Changes between 16 hours behind and 15 hours behind; the PST side is the one that shifts.
- GST to EST Dubai and New York. As of September 2026, EST is 8 hours behind GST. Changes between 9 hours behind and 8 hours behind; the EST side is the one that shifts.
- SGT to GMT Singapore and London. As of September 2026, GMT is 7 hours behind SGT. Changes between 8 hours behind and 7 hours behind; the GMT side is the one that shifts.
Both shift together (4)
- PST to EST The two coasts of the United States. As of September 2026, EST is 3 hours ahead of PST. The gap holds all year.
- CST to EST US Central and US Eastern. As of September 2026, EST is 1 hour ahead of CST. The gap holds all year.
- MST to EST US Mountain and US Eastern. As of September 2026, EST is 2 hours ahead of MST. The gap holds all year.
- CET to GMT Central Europe and the United Kingdom. As of September 2026, GMT is 1 hour behind CET. The gap holds all year.
Both shift, on different dates (4)
- GMT to EST London and New York. As of September 2026, EST is 5 hours behind GMT. Changes between 5 hours behind and 4 hours behind; the briefest run lasts about 7 days at 4 hours behind.
- GMT to PST London and the US West Coast. As of September 2026, PST is 8 hours behind GMT. Changes between 8 hours behind and 7 hours behind; the briefest run lasts about 7 days at 7 hours behind.
- CET to EST Central Europe and the US East Coast. As of September 2026, EST is 6 hours behind CET. Changes between 6 hours behind and 5 hours behind; the briefest run lasts about 7 days at 5 hours behind.
- AEST to EST Sydney and New York. As of September 2026, EST is 14 hours behind AEST. Changes between 16 hours behind and 14 hours behind; the briefest run lasts about 20 days at 15 hours behind; 3 distinct values in the year ahead.
Any other pair
This list is short on purpose: each corridor is one that people search for by abbreviation. For any two cities, the Time Zone Converter translates a date and time between them, DST-correct for that date and with the day change flagged. For a group spread across several zones, the Meeting Planner lines everyone's working hours up side by side. And every city has its own page — for example New Delhi, New York, and London — with a live clock, its current offset, and its next clock change. Each corridor page links to the anchor city on each side that has one.
Frequently asked questions
Does "EST" mean the same thing all year?
No. EST is the standard-time name for New York time; while daylight saving is active the same zone is written EDT (Eastern Daylight Time). People type "EST" year-round regardless, so every converter here reads it as the IANA zone America/New_York and applies whichever of EST or EDT is in force on the date you enter.
Which IST and which CST do these pages mean?
IST here is India Standard Time (Asia/Kolkata); the same letters also mean Irish Standard Time and Israel Standard Time. CST here is Central Standard Time (North America) (America/Chicago); the letters also mean China Standard Time and Cuba Standard Time. Every corridor page names the exact IANA zone behind each abbreviation so you can check it is the meaning you had in mind.
Why does the IST to EST gap change during the year?
As of September 2026, EST is 9:30 hours behind IST. Changes between 10:30 hours behind and 9:30 hours behind; the EST side is the one that shifts. Only the EST side observes daylight saving, so the gap takes 2 values in the year ahead and moves only on EST's transition dates — the other side's calendar plays no part.
Why does the PST to EST gap stay the same all year?
As of September 2026, EST is 3 hours ahead of PST. The gap holds all year. Both sides observe daylight saving and switch at the same instants by the same amount, so the two shifts cancel and the gap never moves.
Why does the GMT to EST gap change during the year?
As of September 2026, EST is 5 hours behind GMT. Changes between 5 hours behind and 4 hours behind; the briefest run lasts about 7 days at 4 hours behind. Both sides observe daylight saving but switch on different dates. Between one side's switch and the other's only one shift has happened, so the gap briefly holds a value it holds only inside these mismatch windows.
Which corridors have no working-hours overlap?
The corridor pages assume a 9:00–17:00 working day on both sides. That is a convention, not a fact about anyone's actual hours — the Meeting Planner lets you set real ones. On that assumption, as of September 2026, IST to EST, IST to PST, GMT to PST, AEST to EST, JST to EST, PHT to PST, and GST to EST have no overlap at all: the whole of one side's day falls outside the other's.
Every figure on this page was computed at build time (September 2026) from the IANA time zone database; none is typed in by hand. The corridor converters run locally in your browser from its own time zone data, and nothing you enter is transmitted. See the methodology page.