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Time Zone Calculator

Convert times between time zones. Enter a date and time, select source and target zones, and see the converted result instantly.

: :
From: (UTC-5) Eastern Time (US/Canada)
2:26:00 PM
14:26:00
Fri, Mar 27, 2026
UTC-5
To: (UTC+9) Tokyo, Seoul
4:26:00 AM
04:26:00
Sat, Mar 28, 2026
UTC+9
Time Difference+14 hours
Day Change+1 day (next day)
From OffsetUTC-5
To OffsetUTC+9

How Time Zones Work

The Earth is divided into time zones based on longitude. Each zone is defined as an offset from UTC (Coordinated Universal Time). Moving east adds hours; moving west subtracts them.

Conversion formula: Target Time = Source Time + (Target Offset - Source Offset)

Major Time Zones

AbbreviationNameUTC OffsetMajor Cities
HSTHawaii Standard-10Honolulu
PST/PDTPacific-8 / -7Los Angeles, Seattle
MST/MDTMountain-7 / -6Denver, Phoenix
CST/CDTCentral-6 / -5Chicago, Houston
EST/EDTEastern-5 / -4New York, Toronto
GMT/BSTGreenwich / British Summer+0 / +1London, Dublin
CET/CESTCentral European+1 / +2Paris, Berlin, Rome
ISTIndia Standard+5:30Mumbai, Delhi
CSTChina Standard+8Beijing, Shanghai
JSTJapan Standard+9Tokyo, Osaka
AEST/AEDTAustralian Eastern+10 / +11Sydney, Melbourne
NZST/NZDTNew Zealand+12 / +13Auckland, Wellington

Daylight Saving Time (DST)

Many regions shift clocks forward by 1 hour in spring and back in fall. During DST, the effective offset changes:

  • US Eastern: EST (UTC-5) → EDT (UTC-4) from March to November
  • UK: GMT (UTC+0) → BST (UTC+1) from March to October
  • No DST: Hawaii, Arizona, Japan, China, India, and most equatorial countries

Quick Reference: Time Differences from UTC

When it's noon (12:00) UTC...Local Time
Los Angeles (PST)4:00 AM
New York (EST)7:00 AM
London (GMT)12:00 PM
Dubai (GST)4:00 PM
Mumbai (IST)5:30 PM
Tokyo (JST)9:00 PM
Sydney (AEST)10:00 PM

Tips for Working Across Time Zones

  • Schedule in UTC: When coordinating across zones, agreeing on UTC avoids confusion
  • Use 24-hour format: Eliminates AM/PM ambiguity across cultures
  • Note the date: Large offsets can shift the date — 10 PM Monday in New York is 12 PM Tuesday in Tokyo
  • Account for DST: Check whether DST is active in both locations at the time of your event
  • International Date Line: Crossing UTC+12/UTC-12 changes the calendar date by one day

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Frequently Asked Questions

How does the time zone calculator work?

Enter a date and time, select the source time zone ("From") and the target time zone ("To"). The calculator converts by finding the UTC equivalent of the source time, then adding the target zone offset.

What is UTC?

UTC (Coordinated Universal Time) is the global time standard. All time zones are defined as offsets from UTC. For example, Eastern Time is UTC-5 and Tokyo is UTC+9, meaning Tokyo is 14 hours ahead of Eastern Time.

Does this account for daylight saving time?

This calculator uses fixed UTC offsets and does not automatically adjust for daylight saving time. If DST is in effect, select the appropriate offset manually (e.g., EDT is UTC-4, EST is UTC-5).

Why do some time zones have half-hour offsets?

Several regions use non-integer offsets: India (UTC+5:30), Nepal (UTC+5:45), Iran (UTC+3:30), Newfoundland (UTC-3:30), and others. These arose from historical, political, and geographical decisions.

What happens when the conversion crosses midnight?

The calculator shows the correct date and indicates the day change. For example, 11 PM in New York (UTC-5) is 12 PM the next day in Tokyo (UTC+9).

How many time zones are there?

There are 38 distinct UTC offsets in use, ranging from UTC-12 (Baker Island) to UTC+14 (Line Islands). Some offsets like UTC+5:45 (Nepal) and UTC+8:45 (Eucla, Australia) are unique to single regions.