Timezone Converter

Timezone Converter — Convert, Find Best Meeting Time & Unix Timestamp

Converting time zones sounds simple until you're scheduling a call with teammates in New York, London, and Tokyo and realize the only "reasonable" hour for all three might not exist. This free timezone converter handles the hard part: it shows every city's current time, highlights when everyone's available with a color-coded heatmap, generates a shareable link your team can open to see the time in their own timezone, and converts Unix timestamps to human-readable dates — all in one place, no signup required.

Whether you're a developer reading API logs with epoch timestamps, a remote team lead scheduling a weekly standup, or a traveler calculating arrival times across continents, this tool was built for your exact use case.

How to Use the Timezone Converter

Converting times across cities takes a few seconds:

1. Add your cities — click "Add City" and search by city name or timezone abbreviation (EST, CET, BRT, JST). Up to 6 cities can be added simultaneously.
2. Choose a date — the date picker at the top lets you check times for any day, which matters for daylight saving transitions where the offset shifts by an hour.
3. Click a time slot in the heatmap — the Best Meeting Time Finder shows 24 color-coded cells: green means all cities are within 9am–6pm working hours, yellow means most are available, red means someone is sleeping. Click any cell to instantly see what time it is in every city at that UTC hour.
4. Share the link — after selecting a time, click "Share Meeting Link" to copy a URL that encodes all your cities and the selected hour. Anyone who opens it sees the conversion in their own context.

Timezone Conversion Examples

Unix timestamp examples:

1714521600  →  May 1, 2024  00:00:00 UTC
             →  Apr 30, 2024 20:00:00 EDT (UTC−4)
             →  May 1, 2024  09:00:00 JST (UTC+9)

1714521600000  (milliseconds in JavaScript — divide by 1000 for seconds)

What Are Time Zones and Why Do They Matter?

A time zone is a region of the globe that observes a uniform standard time offset from UTC (Coordinated Universal Time). There are 24 primary time zones, ranging from UTC−12 to UTC+14, though some zones use 30-minute or 45-minute offsets (India at UTC+5:30, Nepal at UTC+5:45).

The key complication is Daylight Saving Time (DST): roughly 70 countries shift their clocks forward by one hour in spring and back in autumn. This means the offset between two cities can change by one or two hours depending on the time of year — and the transition dates differ between countries. The US switches in early March and November; Europe switches in late March and October. During the "transition window" of a few weeks, common pairs like New York–London have an unusual 4-hour difference instead of the usual 5.

Brazil is a notable exception: it suspended Daylight Saving Time in 2019. BRT (Brasília Time, UTC−3) is now fixed year-round for most of the country.

Common Use Cases

• Remote team standups: A team with members in San Francisco, New York, London, and Berlin needs a 9am–5pm window that works for all four. The heatmap immediately shows that 3pm London (10am NY, 7am SF, 4pm Berlin) is optimal — and generates a shareable link so each person sees the time in their local timezone.
• Developer API debugging: When an API returns 1714521600, the Unix integration panel immediately shows the human-readable date and time in UTC and your local timezone. The millisecond (×1000) / seconds toggle handles the JavaScript vs. Unix convention difference.
• International event announcements: Announcing a product launch or live stream at "3pm PT" and linking the timezone converter means your global audience sees the correct local time without manual calculation.
• Traveler jet-lag planning: Picking the right departure and arrival times across continents involves knowing what time your body thinks it is vs. destination local time — adding both cities answers this instantly.
• Freelancer invoicing: Understanding overlap with clients in different time zones helps set office hours that maximize synchronous communication.

Frequently Asked Questions

What time is 3pm EST in London?

3pm EST (UTC−5, US East Coast in winter) equals 8pm GMT (UTC+0) in London in winter. In summer, the US switches to EDT (UTC−4) and the UK switches to BST (UTC+1), so 3pm EDT equals 8pm BST — still a 5-hour difference, but both offsets changed. During the transition weeks in March and October, the difference can temporarily be 4 or 6 hours. This converter uses the specific date to apply the correct DST offset automatically.

What is a Unix timestamp and how do I convert it?

A Unix timestamp is the number of seconds elapsed since January 1, 1970, 00:00:00 UTC — called the Unix epoch. It is timezone-independent: 1714521600 means the same moment everywhere, regardless of local time. JavaScript uses milliseconds instead of seconds (Date.now() returns 13 digits), so you divide by 1000 to get Unix seconds. The Unix Integration panel on the right shows the current timestamp live and lets you copy it with one click.

Does this converter handle Daylight Saving Time correctly?

Yes. The tool uses the native Intl.DateTimeFormat API, which applies the correct DST rules for each IANA timezone (e.g., America/New_York, Europe/London). When you change the date, the offset label on each city card updates to reflect the DST status on that specific date. The heatmap also recalculates for the selected date.

Does Brazil have Daylight Saving Time?

No — Brazil suspended Daylight Saving Time in 2019. BRT (Brasília Time, UTC−3) is the fixed year-round timezone for most of Brazil, including São Paulo, Rio de Janeiro, and Brasília. Before 2019, clocks advanced to BRST (UTC−2) during summer months. Some Brazilian states use different offsets: AMT (Amazon Time, UTC−4) covers Amazonas and Mato Grosso; ACT (Acre Time, UTC−5) covers Acre; Fernando de Noronha uses UTC−2.

What is the difference between UTC, GMT, and EST?

UTC (Coordinated Universal Time) is the primary global time standard — it has no DST and serves as the reference point for all other zones. GMT (Greenwich Mean Time) is UTC+0, used in the UK during winter; in summer the UK switches to BST (UTC+1). EST (Eastern Standard Time) is UTC−5, used on the US East Coast in winter; in summer it becomes EDT (UTC−4). Saying "EST" in summer is technically wrong — the correct shorthand is "ET" (Eastern Time) when you don't want to specify Standard vs. Daylight.

Resources

• IANA Time Zone Database — The authoritative source for all timezone data used by operating systems and browsers worldwide.
• MDN — Intl.DateTimeFormat — Documentation for the native JavaScript API this tool uses for DST-aware timezone conversions.
• timeanddate.com — DST World Map — Comprehensive map showing which countries observe DST and their transition dates.
• Timestamp Converter — Convert Unix timestamps to human-readable dates and back, with timezone offset support and live epoch counter.