How to Convert Time Zones: Schedule Meetings Across the World

Guides · Calculator · Updated 2026

Scheduling a call between Delhi and New York is a headache if you forget one thing: Daylight Saving Time (DST). India doesn’t observe DST, but the US, UK, and many other countries do — which means the IST‑to‑EST offset shifts from 10.5 to 9.5 hours depending on the month. Manually calculating the correct time is error‑prone. A time zone converter that uses the IANA time zone database and your browser’s built‑in Intl API can do it flawlessly and automatically. Here’s how to use ours and why it always gets DST right.

Why time zone math is tricky

There are over 500 time zones in the IANA database. Each one has its own history of offsets, DST start/end rules, and political changes. For instance, India Standard Time (IST) is always UTC+5:30. Eastern Standard Time (EST) is UTC−5:00 in winter, but Eastern Daylight Time (EDT) is UTC−4:00 in summer. The switch happens on the second Sunday of March and the first Sunday of November — dates that no human should have to memorise. Our tool delegates all that complexity to the Intl.DateTimeFormat API, which is updated automatically by browser vendors when time zone rules change.

Step‑by‑step: convert between time zones

  1. Open the Time Zone Converter tool.
  2. Select the date and time using the datetime‑local input (it defaults to your current local time).
  3. Choose the source time zone from the searchable dropdown. For example, type “Kolkata” to find Asia/Kolkata (IST). Choose the target zone — say, “America/New_York” (EST/EDT).
  4. The converted date and time appears instantly, including the hour difference (e.g., “+9.5 hours”).
  5. Use the quick‑pair buttons for common combinations: IST→EST, IST→GMT, EST→IST, GMT→IST, IST→AEST. For any other combination, the searchable dropdown lists all IANA time zones.
💡 Tip: When inviting a colleague in another time zone, always include the UTC offset or both local times in the invite. “10 AM IST / 11:30 AM EST” avoids confusion. Use the converter to double‑check, especially during DST transition weeks.

Real‑world example: IST to EST

Let’s say you want to schedule a meeting for 8:00 PM IST on July 3rd. In the summer, New York is on EDT (UTC−4:00), so the time difference is 9 hours and 30 minutes. 8:00 PM IST = 10:30 AM EDT the same day. In winter (EST), the difference becomes 10 hours and 30 minutes, shifting the meeting to 9:30 AM. The converter shows this in one step; no manual calendar math needed.

Frequently Asked Questions

What is the difference between UTC and GMT?

In practice, they are the same. UTC (Coordinated Universal Time) is the modern standard, while GMT is a time zone (UTC+0). Most people use them interchangeably.

Does the converter support half‑hour and 45‑minute offsets?

Yes. The Intl API handles all non‑standard offsets, including Nepal (UTC+5:45), India (UTC+5:30), and Chatham Islands (UTC+12:45).

Why does the hour difference sometimes show a fraction?

Because not all time zones are whole hours apart. For example, IST is +5.5 hours from UTC. The converter displays exact decimal differences.

Can I use this for recurring meeting planning?

Yes, but you’ll need to re‑check DST transitions. The converter is excellent for one‑off checks and for setting up a recurring calendar event at the correct local time.

Is it free and private?

Yes — the tool runs entirely in your browser, free, with no sign‑up and nothing uploaded to a server.

Try the Time Zone Converter
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