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Timezone Converter

Time & Speed

Convert time between any two timezones instantly — IST, UTC, EST, GMT, SGT, JST, and 20+ more. Handles DST automatically. Free, in-browser, no sign-up.

Reviewed by the thecalcu.com team · Last updated July 2, 2026

04 Aug 2026, 04:29:00 am GMT-4
ISO 86012026-08-04T04:29:00
UTC04 Aug 2026, 08:29:00 am UTC

What is a Timezone?

A Timezone Converter takes a date and time in one timezone and shows the equivalent moment in another timezone. The underlying time (the UTC moment) does not change, only the local clock representation changes based on the timezone offset.

Timezones are defined by offsets from UTC, ranging from UTC−12 to UTC+14. India Standard Time (IST) is UTC+5:30. When it is 12:00 noon in Mumbai, it is simultaneously 6:30 AM in London (UTC+0 in winter), 1:30 AM in New York (UTC−5 in winter), and 3:30 PM in Singapore (UTC+8). The converter handles all of these translations, including Daylight Saving Time adjustments, automatically.

The converter covers 25 timezones across Asia, Europe, the Americas, and the Pacific, with particular emphasis on zones relevant to Indian users: IST, GST (Dubai), SGT (Singapore), JST (Tokyo), and the major US time zones. DST transitions are handled automatically via the browser's IANA timezone database, you do not need to know whether a date falls in summer or winter time.

For converting Unix timestamps (epoch seconds) to human-readable dates, use the Unix Timestamp Converter. For time duration conversions (hours to minutes, etc.), use the Time Converter.

Why Use a Timezone Converter?

International scheduling requires knowing not just the offset between two timezones but also whether DST is in effect for that specific date. The difference between IST and New York is 9 hours 30 minutes in summer (when the US observes EDT) but 10 hours 30 minutes in winter (when it observes EST). Getting this wrong means missing or double-booking a meeting.

A timezone converter eliminates the mental arithmetic entirely, enter the time, pick the source and target zones, and read the result.

Who Should Use This Converter?

IT and software teams, scheduling standups, releases, or incident calls across globally distributed teams in India, the US, Europe, and Southeast Asia.

Business travellers and expatriates, checking what time a flight, train, or appointment in another timezone corresponds to back home.

Freelancers and remote workers, confirming meeting times sent by international clients, converting deadlines, and ensuring deliveries align with the client's working hours.

Students applying abroad, checking application deadlines, exam registration windows, and university webinar times relative to IST.

Finance and trading desks, monitoring market opening and closing times (NYSE, LSE, BSE, SGX, TSE) in IST.

What Does the Timezone Converter Give You?

  • Converted local time, the date and time in the target timezone, including the timezone abbreviation
  • ISO 8601, the datetime in the target timezone in YYYY-MM-DDTHH:mm:ss format (for use in APIs, calendars, and code)
  • UTC equivalent, the underlying UTC moment (useful for logging and database storage)

The ⇄ button swaps the source and target timezones without re-entering the time.

How to use this Timezone calculator

  1. Enter the Date & Time in the input field, it defaults to the current local time.
  2. Select the From timezone, the zone the entered time is in.
  3. Select the To timezone, the zone you want to convert to.
  4. The converted time appears instantly below, with ISO and UTC outputs.
  5. Click ⇄ to reverse the conversion (swap From and To).
  6. Copy the ISO 8601 output for use in calendar invites, code, or email.

Formula & Methodology

UTC conversion: Given a datetime and source timezone, the browser's Intl.DateTimeFormat API resolves the IANA timezone rules for that specific date (accounting for DST transitions) to compute the UTC offset. The converter applies this offset to find the underlying UTC timestamp.

Display conversion: The UTC timestamp is then formatted in the target timezone using Intl.DateTimeFormat with timeZone: targetTz, producing the local time representation including the correct DST-adjusted offset.

Common IST conversions (winter, no DST):
| IST (UTC+5:30) | UTC | ET (UTC−5) | PT (UTC−8) | SGT (UTC+8) | JST (UTC+9) |
|---|---|---|---|---|---|
| 9:00 AM | 3:30 AM | 10:30 PM (prev) | 7:30 PM (prev) | 11:30 AM | 12:30 PM |
| 12:00 PM | 6:30 AM | 1:30 AM | 10:30 PM (prev) | 2:30 PM | 3:30 PM |
| 6:00 PM | 12:30 PM | 7:30 AM | 4:30 AM | 8:00 PM | 9:30 PM |
| 10:00 PM | 4:30 PM | 11:30 AM | 8:30 AM | 12:30 AM (+1) | 1:30 AM (+1) |

Frequently Asked Questions

The converter uses the browser's built-in Intl.DateTimeFormat API, which applies the IANA timezone database. This means DST transitions are handled automatically, entering a date in summer will use the correct DST offset for that timezone, and entering a winter date will use the standard offset. You do not need to manually account for DST.
IST stands for India Standard Time, the timezone used across all of India (UTC+5:30). India does not observe Daylight Saving Time, so the offset is fixed year-round. IST is one of the few timezones with a half-hour offset, most timezones use whole-hour offsets. Nepal (UTC+5:45) is the only major timezone with a 45-minute offset.
UTC (Coordinated Universal Time) is the primary international time standard against which all other timezones are expressed as positive or negative offsets. It is the successor to GMT for most practical purposes. UTC is preferred in databases, APIs, logs, and server communications because it is unambiguous, it never changes for DST.
Timezones that observe Daylight Saving Time shift their UTC offset by one hour between winter and summer. US Eastern Time is UTC−5 in winter (EST) and UTC−4 in summer (EDT). The label shows both values. The converter calculates the correct offset for the specific date and time you enter.
India Standard Time (IST, UTC+5:30) is 10 hours 30 minutes ahead of US Eastern Time in winter and 9 hours 30 minutes ahead in summer. A 9:00 AM ET meeting is 7:30 PM or 6:30 PM IST depending on the season. Early morning US time (7–9 AM ET) overlaps with IST business hours (5–7 PM IST) and is the most practical window for international calls.
The converter includes 25 major timezones covering Asia, Europe, the Americas, and the Pacific. These cover the timezones most relevant to Indian users doing international work. For a niche timezone not in the list, use the UTC offset of that timezone to calculate manually from the UTC output shown.
No. All conversions run entirely in your browser using the browser's built-in Intl.DateTimeFormat API. No datetime or location data is sent to a server.
GMT (Greenwich Mean Time) and UTC are effectively the same for most purposes and share the same offset (UTC+0). The technical difference is that GMT is a timezone that can be adjusted for DST (in the UK, it becomes BST at UTC+1 in summer), while UTC is an atomic time standard that never adjusts. In common usage, GMT and UTC are interchangeable for the UTC+0 offset.
Singapore Standard Time (SGT) is UTC+8. IST is UTC+5:30. The difference is 2 hours 30 minutes, Singapore is ahead. So 9:00 AM IST = 11:30 AM SGT. Enter the IST time in the converter with 'From' set to Asia/Kolkata and 'To' set to Asia/Singapore to get the exact converted time.
Dubai and the UAE use Gulf Standard Time (GST), which is UTC+4. There is no Daylight Saving Time in the UAE. IST (UTC+5:30) is 1 hour 30 minutes ahead of Dubai time. A flight departing Mumbai at 2:00 AM IST lands in Dubai (local time) at 3:30 AM GST, no DST adjustment needed.
When converting across large timezone differences, the local date in the target timezone may differ from the source date. For example, 11:00 PM IST on Thursday converts to 12:30 PM ET on Thursday (US Eastern, UTC−5:30 difference = 10.5 hours behind). But 1:00 AM IST on Friday would convert to 2:30 PM ET on Thursday, the previous calendar day.
Also known as
IST to EST convertertime zone converterIST to UTCconvert time zonesIndia time to US timeworld clock converterUTC to local timemeeting time zone converterGMT to ISTPST to EST