How to Convert Time Between Time Zones Online

To convert time between zones, enter a source date and time, choose the zone it belongs to, and add one or more target zones — each shows the converted local time, its UTC offset, and a badge when the date rolls over. Daylight saving is applied automatically, so you never add or subtract an hour by hand.

This guide explains how to schedule confidently across continents, why the converted time sometimes lands on a different day, and which zone names to trust when it matters.

Why time zone conversion is harder than it looks

Time zones are not fixed offsets — most shift by an hour twice a year for daylight saving, and the switch dates differ by country and change over time. Abbreviations make it worse: "IST" means both Indian and Irish Standard Time, and "EST" is ambiguous outside North America. For remote teams booking meetings between New York, London, Karachi, Singapore and Sydney, or travellers checking an arrival time, guessing the offset is a recipe for a missed call. A converter that reads the live IANA rules removes that risk.

How to convert time zones in your browser

1. Enter the source date and time you want to convert.
2. Choose the time zone that date and time belongs to.
3. Add one or more target zones with the "Add zone" button.
4. Read each converted time with its UTC offset and a +1 or −1 day badge when the calendar date changes.

UTC, GMT and IANA names explained

A little terminology makes scheduling much clearer:

Term	What it is	Example
UTC	The modern global time standard	UTC+0, never shifts for DST
GMT	Historic name for the same UTC+0 offset	Used interchangeably with UTC
IANA zone	A region whose offset can change	America/New_York (UTC−5 or −4)
Abbreviation	Ambiguous short label	IST, EST — avoid for scheduling

Because the tool uses IANA names like Europe/London or Asia/Kolkata, results are unambiguous and always reflect the correct offset for the exact date you pick.

Key features

• Convert between hundreds of IANA time zones.
• Common zones pinned to the top of every list.
• Automatic daylight saving time handling.
• UTC offset shown for the source and every target zone.
• Day-difference badge when a converted time crosses midnight.
• Compare many zones at once, all processed locally and offline.

Try the Time Zone Converter now — it's free and runs entirely in your browser.

Frequently asked questions

How does the converter handle daylight saving time?

It uses your browser's built-in IANA database, which knows the exact DST start and end dates for every zone and year. The offset shown is correct for the specific date you choose, so no manual adjustment is needed.

What is the difference between GMT, UTC and a time zone?

UTC is the modern global standard and GMT is the historic name for the same UTC+0 offset. A time zone like America/New_York is a region whose offset from UTC shifts with daylight saving — UTC−5 in winter, UTC−4 in summer.

Why does the converted time show a different date?

When the time difference pushes past midnight, the target zone is already on the next day or still on the previous one. The +1 or −1 day badge flags this so you never book a meeting on the wrong date.

Can I convert one time into several zones at once?

Yes. Click "Add zone" to append as many target rows as you need — handy for announcing a single event time to audiences in Europe, Asia and the Americas together.

Which zone names should I use for scheduling?

Prefer IANA names like Europe/London or Asia/Kolkata over abbreviations such as EST or IST, which are ambiguous. This converter uses IANA names exactly, so the results are never in doubt.

Related free tools

• Timestamp Converter — convert between dates and timestamps.
• Unix Timestamp Converter — work with epoch time precisely.
• Countdown Timer — count down to an event across zones.
• Date Difference Calculator — measure the gap between two dates.

Built by ByteVancer

ByteTools is a free product of ByteVancer, a software and web development studio that builds web apps, SaaS platforms and custom software for businesses. If your app needs robust scheduling or time-zone handling, explore ByteVancer's services or get in touch to start a project.