Developer

Time Zone Converter

Compare up to four time zones side-by-side with a live 24-hour grid. Search by city, country, IANA ID, or abbreviation (GMT, NPT, IST, EST…), star favorites, and pick a meeting time that works everywhere.

Tool Summary Answer Block

This tool accepts structured input and returns deterministic output in the browser with no server upload.

Tool name: Time Zone Converter
Input intent: Provide source content to transform, validate, or analyze.
Output intent: Receive normalized output suitable for copy, reuse, or debugging.
Example input: GMT ↔ NPT
Example output: GMT 09:00 → NPT 14:45 (same day)

Tool Introduction

Tool Overview

The time zone converter helps you plan calls, releases, and travel across regions without doing the math in your head. Type Kathmandu, Nepal, NPT, or Asia/Kathmandu — they all resolve to the same zone. Add up to four cities and the tool draws a 24-hour strip for each one, anchored to the reference zone's local day. Click any hour cell to mark a meeting time and instantly see what it lands on in every other zone (and whether it crosses a day boundary). Everything is computed in your browser using the IANA database via the standard Intl APIs, so daylight-saving transitions are handled correctly and no data leaves your device. Favorite zones, your home zone, your last comparison, and your 12h/24h preference are saved in cookies on this device — clear cookies to reset.

Use Cases

Schedule a meeting between teammates in Kathmandu (NPT) and London (GMT/BST).
Coordinate a release window across IST and EST without arithmetic.
Plan a call that respects working hours in three or four offices at once.
Quickly check what time it is in any major city before sending a message.

Input/Output Examples

Nepal is UTC+5:45, an unusual 45-minute offset.

Input Intent

GMT ↔ NPT

Output Intent

GMT 09:00 → NPT 14:45 (same day)

India is UTC+5:30; New York is UTC−5 (or UTC−4 during DST).

Input Intent

IST ↔ EST

Output Intent

IST 21:00 → EST 10:30 (same day)

Many Sydney mornings are still the previous calendar day in New York.

Input Intent

Sydney ↔ New York

Output Intent

Sydney Mon 09:00 → New York Sun 17:00

FAQ

Does it handle daylight saving time?+

Yes. Offsets and abbreviations come from the IANA tz database via the browser's Intl API, which knows DST rules and historical changes for every supported zone.

Why does an hour sometimes show '+1d' or '−1d'?+

When a zone is far enough ahead or behind the reference zone, the same instant falls on the next or previous calendar day. The day badge tells you so you do not book Monday in one city and accidentally land on Tuesday in another.

Where are my favorites stored?+

In a cookie on this device only. Nothing is sent to a server. Clear your browser cookies for this site to reset favorites and preferences.

Can I compare more than four zones?+

Four is the cap to keep rows readable on phones and laptops. Remove a zone first if you want to swap one in.

What does the 'reference' label mean?+

The top zone defines which local day the 24-hour grid is anchored to. Reorder rows with the up/down arrows to make a different zone the reference.