What This Calculator Does

This time zone converter translates a specific date and time from one IANA time zone to another. It displays the converted time along with the UTC offset for both the source and destination zones. The converter handles daylight saving time transitions automatically using the comprehensive IANA time zone database.

Inputs Explained

Date & Time: The date and time you want to convert, entered in your local datetime format (YYYY-MM-DDTHH:MM).
From Zone: The source time zone — the zone the entered date and time currently represents.
To Zone: The destination time zone — the zone you want to convert to.

How It Works

The converter uses the Luxon date-time library, which internally references the IANA Time Zone Database (also known as the Olson database or tzdata). When you select a "From" zone and a "To" zone, Luxon interprets your input datetime in the source zone, converts it to UTC internally, and then converts from UTC to the destination zone. This two-step process through UTC ensures accurate conversion even when daylight saving transitions differ between zones.

Formula Used

Converted Time = Input Time − Source UTC Offset + Destination UTC Offset
(Internally: Input → UTC → Destination zone)

Time Zone Converter

Convert date and time between different locations.

Step-by-Step Example

Input: January 31, 2026, 10:00 AM

From Zone: America/New_York (UTC−05:00 in January, Eastern Standard Time)

To Zone: Asia/Kolkata (UTC+05:30, India Standard Time)

Step 1: Convert 10:00 AM EST to UTC → 10:00 + 5:00 = 15:00 UTC.

Step 2: Convert 15:00 UTC to IST → 15:00 + 5:30 = 20:30 IST.

Result: 8:30 PM on January 31, 2026 in India (same day, 10.5 hours ahead).

Use Cases

Meeting scheduling: Find a mutually convenient time for participants across different continents.
Remote work coordination: Know when colleagues in other time zones start and end their workday.
Travel planning: Check what time it will be at your destination when you depart or arrive.
Broadcasting and live events: Convert event start times for a global audience.
International finance: Coordinate trading activities across markets that operate in different time zones.

Assumptions and Limitations

The converter uses the IANA time zone database, which is updated several times per year. Very recent legislative changes to daylight saving rules may not yet be reflected.
Daylight saving time is handled automatically — the offset applied depends on the specific date entered, not just the zone name.
Some time zones have half-hour or 45-minute offsets (e.g., India at UTC+05:30, Nepal at UTC+05:45).
Historical time zone data before 1970 may be less reliable. For conversions involving dates before 1970, results should be treated as approximate.
The zone list is populated from your browser's Intl API. Rare or deprecated zone names may not appear.

Frequently Asked Questions

Does the time zone converter handle daylight saving time?

Yes. The converter uses the IANA time zone database via the Luxon library, which contains historical and future daylight saving time rules for every region worldwide. When you enter a date, the converter automatically applies the correct offset for that specific date and zone, whether standard time or daylight saving time is in effect.

What is the IANA time zone database?

The IANA time zone database, also called tzdata or the Olson database, is the most widely used source of time zone and DST data worldwide. It is maintained by the Internet Assigned Numbers Authority and is updated several times per year. It is used by Linux, macOS, Java, PHP, Python, and most other software systems.

How do I convert UTC to my local time?

Select 'UTC' as the From Zone and your local time zone as the To Zone. Enter the UTC time you want to convert, then click Convert Time. The result will show the equivalent time in your local zone with the correct offset applied.

Why do some time zones have half-hour or 45-minute offsets?

Some countries adopted offsets that do not align with whole hours. India uses UTC+05:30, Iran uses UTC+03:30, and Nepal uses UTC+05:45. These offsets are historical and political decisions, not based on strict geographic longitude. The converter handles all such non-standard offsets correctly.

Can I convert times for a future date?

Yes, you can enter any future date and time. The converter will apply the DST rules that are currently expected for that date. However, if a government changes its DST policy before that date, the prediction could become inaccurate until the IANA database is updated.

What happens during a daylight saving time transition?

During a 'spring forward' transition, one hour is skipped — times in that gap do not exist. During a 'fall back' transition, one hour is repeated — times in that overlap could refer to either standard or daylight time. The converter resolves these ambiguities using the Luxon library's default behavior.

How many time zones are there in the world?

The IANA database defines over 400 time zone identifiers, but many are aliases. In practice, there are roughly 38 distinct UTC offsets in use worldwide, ranging from UTC−12:00 to UTC+14:00. The number changes slightly as countries modify their offset or DST rules.

Is there a time zone called GMT and is it the same as UTC?

GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) are often used interchangeably for everyday purposes. Technically, UTC is the modern standard maintained using atomic clocks, while GMT is the older astronomical time standard. For practical civilian purposes, they have the same offset of zero hours.

Sources and References

IANA Time Zone Database — The authoritative source for global time zone data used by the Luxon library in this converter.
RFC 6557 – Procedures for Maintaining the Time Zone Database — IETF standard documenting the maintenance procedures for the IANA tz database.
Luxon Documentation — The JavaScript date-time library used for zone conversions and DST handling.
National Institute of Standards and Technology – Time Zones — NIST reference on UTC and time distribution.
Schema.org FAQPage Specification — Structured data specification for the FAQ markup on this page.