ReckonBoxHow the time zone converter works
A time zone converter takes one moment written as a wall-clock reading in one place and shows the same moment everywhere else, by applying each zone's offset from UTC on that date. Set a date, a time and a source zone, add as many destination zones as you need, and every reading comes back with its UTC offset, its date, and a note if it lands on the day before or after.
The date field is doing more work than it looks. Offsets are not fixed properties of a place: they move when a country shifts its clocks, so 9:00 in London converts differently in January and in July. This tool looks up the offset for the exact date you enter, using the time zone database your browser already carries, so daylight saving is handled without a setting you could get wrong.
Why do two sites give different India to US time differences?
Because they're describing different halves of the year without saying so. Measured against true Eastern Standard Time, India runs 10 hours 30 minutes ahead of New York. From March to November, though, New York is on Eastern Daylight Time and the gap closes to 9 hours 30 minutes. Both numbers are correct; neither is complete on its own.
Checking the top results for that query on 18 July 2026 turned up exactly this split. One well-known converter reported the gap as 9.5 hours, another as 10:30, and only one of the three bothered to mention India's UTC offset at all. None of them explained the discrepancy, which leaves a reader with two contradictory answers and no way to tell which applies to their meeting.
| Season | New York clock | Gap to India |
|---|---|---|
| Winter (November to March) | Eastern Standard Time, UTC-05:00 | 10 hours 30 minutes |
| Summer (March to November) | Eastern Daylight Time, UTC-04:00 | 9 hours 30 minutes |
So 7:00 am in New York is 5:30 pm in India in January, and 4:30 pm in July. Book a recurring call in February and it silently moves an hour for one side in March.
Does India observe daylight saving time?
India Standard Time sits at UTC+5:30 for the whole year, and Indian clocks never move for daylight saving. That single fact explains every seasonal wobble in an India to US or India to Europe schedule: the movement always comes from the other end. Savvy Time states it plainly, and it's the piece the two biggest pair pages leave out.
Plenty of the world sits still like this. The half-hour offset is worth a look too, since India is one of a handful of places that isn't a whole number of hours from UTC, and Nepal goes further at UTC+5:45.
When do the clocks change?
Clock changes happen on dates set by each jurisdiction, not on a single worldwide day. In 2026 the United States and Canada moved forward from 02:00 to 03:00 on Sunday 8 March and go back from 02:00 to 01:00 on Sunday 1 November. Most of Europe moved forward on Sunday 29 March and returns on Sunday 25 October, with the UK shifting from 01:00 to 02:00.
| Region | 2026 forward | 2026 back |
|---|---|---|
| United States and Canada | Sunday 8 March | Sunday 1 November |
| Most of Europe | Sunday 29 March | Sunday 25 October |
Three weeks separate the US and European spring changes, which is the window when a London to New York call drifts by an hour before settling back. The southern hemisphere runs opposite: New Zealand and Australia shift in April and September, so an Australian summer is a European winter.
What is the IANA time zone database?
The IANA Time Zone Database, known as tz or zoneinfo, records the history of local time around the world, including UTC offsets and daylight-saving rules. Release 2026c was published on 8 July 2026. It's maintained under procedures set out in BCP 175, and it keeps being republished because governments keep changing zone boundaries, offsets and clock rules.
That's the case against hardcoding. A converter carrying a fixed table of offsets is accurate only until the next country amends its law, and it can't be right in both March and July for anywhere that observes summer time. One top-ranked time zone calculator says outright that it doesn't consider daylight saving in its calculations, which makes it wrong for roughly half the year for any zone that observes it, even while the same page carries a long explainer about what daylight saving is.
Why zone names beat abbreviations
Abbreviations look friendly and are genuinely ambiguous. IST is India Standard Time and also Irish Standard Time. CST covers the US Central zone, China and Cuba. Picking one from a list gives you no way to know which country you just selected.
The database names an Area and a Location instead, like Asia/Kolkata or America/New_York, so exactly one place is described. There's a wrinkle worth knowing: the list a browser reports still files some cities under names they've moved on from, so India appears as Asia/Calcutta, Ukraine's capital as Europe/Kiev, and Myanmar's city as Asia/Rangoon. Both spellings resolve to the same moment, so this page shows the current name, which is the one you'd actually search for.
What this converter does not do
It converts an instant precisely and stops there. Finding an hour that suits everyone across three continents is a meeting planner's job, and the dedicated planners do it well. It also keeps to modern dates, since the database's record of local time before 1970 is documented as best-effort only.
Dates far in the future are computed on today's rules and should be read that way, because a government can change its daylight saving law with a few months' notice. For arithmetic on plain clock times with no zones involved, the time calculator is the tool, and for totting up a week of shifts the hours calculator takes over.
Frequently asked questions
How does a time zone converter work? A time zone converter turns a wall-clock reading in one place into the same moment somewhere else, by applying each zone's offset from UTC on that date. This tool reads those offsets from the IANA time zone database your browser carries, so a date in March and a date in July can give different answers whenever a zone shifts its clocks.
What is the time difference between India and New York? India is 10 hours 30 minutes ahead of New York in winter and 9 hours 30 minutes ahead in summer. The gap moves because New York switches to daylight time while India never changes its clocks, so 7:00 am in New York is 5:30 pm in India in January but 4:30 pm in July.
Why do two websites give different India to US time differences? Because they are answering about different halves of the year without saying so. Against true Eastern Standard Time the gap with India is 10 hours 30 minutes, but from March to November New York runs on Eastern Daylight Time and the gap is 9 hours 30 minutes. A converter that ignores daylight saving prints one figure all year and is wrong for about half of it.
Does India observe daylight saving time? No. India Standard Time sits at UTC+5:30 for the whole year and Indian clocks never move for daylight saving. That is why every seasonal change in an India to US or India to Europe gap comes from the other country moving, never from India.
When do the clocks change in 2026? In the United States and Canada clocks went forward from 02:00 to 03:00 on Sunday 8 March 2026 and go back from 02:00 to 01:00 on Sunday 1 November 2026. Most of Europe moved forward on Sunday 29 March 2026 and returns on Sunday 25 October 2026, with the UK shifting from 01:00 to 02:00. The southern hemisphere runs the opposite way, so New Zealand and Australia shift in April and September.
What is the IANA time zone database? The IANA Time Zone Database, often called tz or zoneinfo, records the history of local time worldwide including UTC offsets and daylight-saving rules, and release 2026c was published on 8 July 2026. It exists because governments keep changing zone boundaries, offsets and clock-change rules, so any converter that hardcodes offsets goes stale the moment a country amends its law.
Why use names like Asia/Kolkata instead of abbreviations like IST? Abbreviations are ambiguous: IST means India Standard Time and also Irish Standard Time, and CST covers the United States Central zone, China and Cuba. The IANA identifiers name an Area and a Location, such as Asia/Kolkata or America/New_York, so there is exactly one place being described. The abbreviation appears in the result as a label only.
Can I convert a date far in the future? Yes, though the answer uses the clock-change rules in force today. Governments alter daylight saving rules with little notice, so a conversion for a date years ahead is a projection on current law and can move if a country changes its mind.