Timezone Converter

WHAT IT DOES

Timezone Converter shows you the current time in multiple timezones simultaneously, making it easy to coordinate with people around the world. The tool displays a list of timezones with their current time, date, and UTC offset. You can add any city or timezone with a custom UTC offset, and remove timezones you don't need. The clocks update every second in real time. The tool supports 12-hour and 24-hour time formats, shows or hides the date, and auto-detects your local timezone. Daylight saving time is automatically handled for named timezones.

WHERE IT RUNS

The extension runs entirely within your browser's local environment using the BotGentz framework. All time calculations, timezone conversions, and clock rendering occur on your machine without any network requests. No time data, timezone preferences, or user activity is ever transmitted, uploaded, or stored externally. The tool works on any website and respects the browser's security boundaries, operating within the isolated extension sandbox. Timezone conversion uses the browser's Intl.DateTimeFormat API and JavaScript Date objects.

HOW TO USE

Click the extension toolbar icon to open the Timezone Converter panel. The panel shows a list of timezones with their current time, date, and UTC offset. Use the "Add Timezone" section to add a new timezone: enter a label (e.g., "Tokyo") and a UTC offset (e.g., 9 for UTC+9), then click "Add". Use the preset buttons to quickly add common timezones like London, New York, Tokyo, and Sydney. Click the "✕" button next to any timezone to remove it. Toggle "12-hour format" to switch between 12-hour and 24-hour time display. Toggle "Show date" to show or hide the date below each time. Toggle "Auto-detect timezone" to use your browser's detected timezone. Click "Refresh" to manually update all clocks. Click "Reset to Defaults" to restore the default timezone list. The clocks update every second automatically.

THE TIMEZONE ENGINE — WHY IT WORKS

Most timezone converters rely on fixed offsets or external APIs that require network requests. This tool uses the browser's built-in Intl.DateTimeFormat API with the timeZone option, which provides accurate timezone conversions using the system's timezone database. For named timezones (e.g., "America/New_York"), the API automatically handles daylight saving time transitions. For custom timezones with fixed UTC offsets, the tool uses a fallback calculation that adds the offset to the current UTC time. The engine renders each timezone's time using toLocaleString with the appropriate timeZone, ensuring accuracy. The auto-detect feature uses Intl.DateTimeFormat().resolvedOptions().timeZone to get the user's current timezone. The clock updates every second using setInterval, with the interval stored for cleanup on page unload. This combination of native API usage and fallback calculations provides accurate timezone conversion without any external dependencies.

THE PANEL

The Timezone Converter panel is fully draggable by its title bar and remembers its position on screen per website. It snaps to the edges of your browser window for clean alignment. Collapse the panel to a compact icon strip using the minimize button, restoring it with a single click. Resize the panel by dragging any edge or corner; the clock list and controls adjust proportionally. Press the Escape key to close the panel instantly. The panel maintains independent state for each browser tab, allowing you to view timezones in multiple tabs simultaneously.

PLEASE NOTE

This extension requires the free BotGentz extension framework to be installed and enabled. Named timezones (e.g., "America/New_York") should use IANA timezone database names for best results. Custom timezones with fixed offsets do not account for daylight saving time changes. The tool uses your system's timezone database; timezone data may vary between browsers and operating systems. All time data is processed locally and is never transmitted, logged, or shared. The extension requests no network permissions and functions entirely offline. The source code is fully auditable and available for review.