About this tool
A time zone converter shows the same instant in time across different parts of the world. Every city on Earth measures time relative to Coordinated Universal Time (UTC), and that offset shifts depending on geographic location and whether daylight saving time is in effect.
This tool lets you add as many cities as you need, then compare them on a single 24-hour timeline. Scrub through the day to see what 9 AM in New York looks like in London, Tokyo, or Sydney. Cross-day badges automatically flag when a time falls on a different calendar date in another zone — a common source of meeting confusion.
How to use it
- 1Click "Add timezone" and search for a city or region (e.g. "Tokyo", "America/Chicago").
- 2Use the scrub slider to move through the day. All cities update simultaneously.
- 3Pick a reference date to see how times behave across DST transitions or weekends.
- 4Click "Copy shareable link" to send the current view to a colleague — they will see the exact same setup.
Common use cases
- Scheduling international meetings across two or more offices
- Coordinating with remote teammates in different countries
- Planning customer calls or webinars for a global audience
- Confirming flight arrival times in the destination timezone
- Watching live sports, conferences, or product launches happening abroad
- Checking when family or friends overseas are likely to be awake
How it works
The browser uses the Intl.DateTimeFormat API to compute each zone's current UTC offset, including DST adjustments that the underlying IANA timezone database supplies.
When you change the time on one zone, the tool converts your local time to UTC and then projects it back into every other zone — so the displayed times always represent the same moment in absolute time.
Frequently asked questions
How accurate is this converter?
The tool uses the IANA timezone database that ships with your browser, the same source operating systems use. It accounts for DST transitions, historical offset changes, and politically defined time zones.
Why do some cities show "+1d" or "-1d" next to them?
That badge means the local date is one day ahead of or behind the reference zone. Without it, you might book a Monday 11 PM meeting in Los Angeles thinking it is a Monday in Tokyo — but Tokyo is already on Tuesday afternoon.
Can I save my favorite timezones?
Yes. The cities you select are encoded in the URL, so you can bookmark the page or share the link. Every visit will restore your exact setup.
Does it handle daylight saving time correctly?
Yes. DST transitions are built into the IANA timezone data, so if you scrub the timeline across a "spring forward" or "fall back" moment, you will see the offset change in real time.
What is the difference between UTC and GMT?
For everyday purposes they are the same. UTC is the modern atomic-clock-based standard; GMT is the older astronomical standard tied to the Royal Observatory in Greenwich. Time zones are technically defined as offsets from UTC.