Timezone Compare: A Simple Tool for Remote Teams

The Problem with Timezones

Working with remote teams across different timezones can be challenging. Whether you're scheduling meetings with colleagues in different countries or trying to figure out the best time to deploy code that won't disrupt users, timezone math is something we all deal with.

I often found myself:

Opening multiple world clock apps
Calculating time differences manually
Missing meetings because of timezone confusion
Wondering "What time is it for my teammate in Austin right now?"

So I built a simple tool to solve this: Timezone Compare.

Features

The timezone compare tool includes:

Real-Time Clock Display

Each timezone shows a live clock that updates every second, so you always see the current time in each location.

Pre-configured Cities

I've included the cities I work with most frequently:

Jakarta (GMT+7) - Where I'm based
Austin, Texas (GMT-6) - Central Time
Ukraine (Kyiv) (GMT+2) - Eastern European Time

Plus popular locations like New York, London, Tokyo, Singapore, and more.

Automatic Time Difference Calculation

When you add multiple cities, the tool automatically calculates the time difference between them. This makes it easy to see:

How many hours ahead/behind each location is
Which teammates are in the same working hours
The best time for team meetings

Clean, Responsive Interface

The tool uses a card-based layout that adapts to mobile, tablet, and desktop screens. Each timezone card shows:

City name
Current time (HH:MM:SS format)
Current date
GMT offset
IANA timezone identifier
Time differences from other selected timezones

How to Use It

Using the timezone compare tool is straightforward:

Visit the tool: Navigate to /playground/timezone-compare
Add cities: Select a city from the dropdown menu
Click "Add City": The timezone card appears with real-time updates
Compare times: Each card shows the time difference from previously added cities
Remove cities: Click the X button on any card (except the last one)

Use Cases

Here are some practical scenarios where this tool helps:

Scheduling Meetings

You're in Jakarta (18:00) and need to schedule with:
- Austin colleague (05:00, -13 hours)
- Ukraine teammate (12:00, -6 hours)

Best meeting time: Jakarta 15:00 = Austin 02:00 ❌ = Ukraine 09:00 ✅
Better option: Jakarta 20:00 = Austin 07:00 ✅ = Ukraine 14:00 ✅

Deployment Planning Check when different regions are in low-traffic hours to schedule deployments without disrupting users.

Remote Team Awareness Keep the tool open to always know what time it is for your teammates. This helps avoid messaging someone at 2 AM their time!

Technical Implementation

The tool is built with:

Next.js 14 with App Router
React Hooks for state management (useState, useEffect)
Intl.DateTimeFormat API for timezone conversions
Tailwind CSS for styling

Key technical features:

Timezone Handling

const formatter = new Intl.DateTimeFormat('en-US', {
  timeZone: tz.timezone,
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
  hour12: false,
})

The browser's Intl.DateTimeFormat API handles all timezone conversions accurately, accounting for daylight saving time changes automatically.

Real-time Updates

useEffect(() => {
  const updateTimes = () => {
    // Update all times
  }
  updateTimes()
  const interval = setInterval(updateTimes, 1000)
  return () => clearInterval(interval)
}, [timezones])

A setInterval updates all clocks every second, and cleanup happens on component unmount.

Time Difference Calculation

const getTimeDifference = (tz1: TimeZone, tz2: TimeZone): string => {
  const diff = tz2.offset - tz1.offset
  const hours = Math.floor(Math.abs(diff))
  const minutes = Math.abs((diff % 1) * 60)
  const sign = diff > 0 ? '+' : '-'
  return `${sign}${hours}${minutes > 0 ? `:${minutes}` : ''} hours`
}

Building with AI Assistance

This tool was built with help from GitHub Copilot and AI-powered development tools. Here's how AI assisted in the development process:

Code Generation

AI helped generate boilerplate code and common patterns:

React component structure with TypeScript types
State management hooks (useState, useEffect)
Tailwind CSS utility classes for styling
Time formatting and calculation logic

Problem Solving

When I encountered challenges, AI provided solutions:

Timezone conversion: Suggested using Intl.DateTimeFormat API instead of manual calculations
Performance optimization: Recommended cleanup in useEffect to prevent memory leaks
Type safety: Helped define proper TypeScript interfaces for timezone data

Best Practices

AI pointed out improvements I might have missed:

Proper cleanup of setInterval on component unmount
Accessibility considerations (aria-labels for remove buttons)
Responsive design patterns for mobile/tablet/desktop
Error handling for invalid timezone data

Time Savings

What would have taken several hours of research and trial-and-error was completed much faster with AI assistance. This let me focus on:

User experience design
Selecting the right cities for pre-configuration
Testing the tool with real-world scenarios
Writing this documentation

The Human Touch

While AI is incredibly helpful, the important decisions were still human:

Feature selection: Which cities to include based on my actual team locations
UI/UX design: The card-based layout and color scheme matching my site theme
Use case identification: Real problems I face daily with timezone coordination
Code review: Understanding every line of AI-generated code before using it

AI is a powerful tool, but it's just that—a tool. The vision, problem-solving, and quality control still come from the developer.

Future Improvements

Some ideas for future enhancements:

Custom Timezones: Allow users to add any IANA timezone, not just pre-configured cities
Saved Preferences: Remember selected timezones using localStorage
Meeting Scheduler: Highlight optimal meeting times based on work hours
Shareable Links: Generate URLs with pre-selected timezones
12/24 Hour Format Toggle: User preference for time display
Dark/Light Theme: Match the site's theme switching

Why Build This?

You might wonder, "Aren't there dozens of timezone tools already?" Absolutely! But building your own tools has benefits:

Customization: I can add exactly the cities I need
Learning: Great practice with Intl API and React hooks
Integration: Lives alongside my other tools in the playground
No Ads: Clean, distraction-free interface
Control: I own the code and can modify it anytime

Try It Out

Head over to /playground/timezone-compare and give it a try. Whether you're coordinating with remote teams, planning international travel, or just curious about what time it is around the world, I hope you find it useful!

Found a bug or have a feature request? Let me know!

Related Tools

Check out other tools in the Playground:

JSON Beautifier: Format and validate JSON data
More tools coming soon...

Resources

IANA Time Zone Database
MDN: Intl.DateTimeFormat
World Time Buddy - Another great timezone tool