Timezone Converter & Meeting Planner
Visual timezone comparison with 400+ IANA zones, working hours overlap detection, and calendar export.
How to Use
Compare times across multiple timezones instantly with a visual hour grid. All conversions use your browser's built-in timezone database — no external API calls.
- Your local timezone is auto-detected and shown first. Change the date and time inputs to convert a specific moment.
- Add timezones by typing a city name, country, or IANA identifier (e.g., "Tokyo", "Europe/London") in the search field. Each timezone appears as a row with its current time and a 24-hour grid.
- Read the hour grid: Green cells are working hours (9 AM – 5 PM), dark cells are nighttime, and the highlighted cell shows the current hour. When multiple zones overlap in working hours, a stronger green indicates the ideal meeting window.
- Export to calendar: Click "Export .ICS" to download a calendar event file, or "Google Calendar" to open the event directly in your Google Calendar.
- Copy summary: The copy button creates a plain-text summary of all timezone conversions for pasting into emails or chat.
About This Tool
IANA Timezone Database
This tool uses the IANA Time Zone Database (also known as the Olson database or tz database), the same authoritative source used by operating systems, programming languages, and web browsers worldwide. The database contains over 400 timezone identifiers covering every inhabited region on Earth, including historically significant offset changes. Your browser keeps this database updated automatically with OS and browser updates, so conversions remain accurate even when governments change their timezone rules.
Daylight Saving Time Handling
DST transitions are handled automatically by the browser's Intl.DateTimeFormat API. When you select a future date, the tool calculates the correct offset for that specific date — not the current offset. This matters because a meeting scheduled for July between New York (EDT, UTC-4) and London (BST, UTC+1) has a 5-hour difference, while in January (EST/GMT) it's only 5 hours. The DST badge on each timezone row indicates when daylight saving time is currently in effect.
Non-Standard Offsets
Not all timezones follow whole-hour offsets from UTC. India Standard Time is UTC+5:30, Iran Standard Time is UTC+3:30, Afghanistan is UTC+4:30, Nepal is UTC+5:45, and the Chatham Islands observe UTC+12:45. The Marquesas Islands use UTC-9:30. This tool correctly handles all these fractional offsets, including their DST transitions where applicable.
Working Hours Overlap
The meeting planner feature automatically identifies hours where all selected timezones fall within standard business hours (9 AM – 5 PM). For two zones with a 5-hour difference (e.g., New York and London), the overlap window is typically 3 hours. For zones 12+ hours apart (e.g., New York and Tokyo), there may be zero overlap during standard business hours. The visual grid makes these overlaps immediately obvious without any calculation.
Why Use This Tool
Visual Over Numerical
Most timezone converters show numerical UTC offsets and expect you to do mental arithmetic. Our visual hour grid shows day and night at a glance — you can instantly see that when it's 9 AM in New York, it's 2 PM in London and 11 PM in Tokyo, without converting any numbers. The color-coded grid communicates working hours, nighttime, and meeting overlap windows in a way that raw numbers cannot.
Everything runs 100% client-side using your browser's native Intl API. No external API calls, no server processing, no tracking. The timezone database comes from your operating system and stays current with browser updates.