Time zones aren't arbitrary — they trace back to a real problem railroads created in the 1800s. Before then, towns set their own local time by the sun. That worked fine when travel was slow. But a train schedule falls apart if every station keeps a different clock. Standardizing time across whole regions solved that problem. It's the same basic system every device's clock, including this one, still relies on today. Time zone boundaries and daylight saving rules are tracked in the IANA Time Zone Database. It's the shared reference nearly every computer and phone uses.
World Clock
Compare times around the world
New York
USA
08:02 AM
Thu, Aug 6 · GMT-4
London
UK
01:02 PM
Thu, Aug 6 · GMT+1
Istanbul
Turkey
03:02 PM
Thu, Aug 6 · GMT+3
Tokyo
Japan
09:02 PM
Thu, Aug 6 · GMT+9
About this world clock
Add any city and its live local time appears right away, updating every second. Daylight saving changes are handled automatically for every city on your list, so you never need to adjust anything by hand.
Common uses: scheduling a call across time zones, checking whether a colleague in another city is still in their workday, or simply keeping a few cities you care about visible at a glance.
When a city's local date differs from your device's date — because the time difference crosses midnight — a "Tomorrow" or "Yesterday" badge appears next to its name so the comparison stays unambiguous.
Your selected cities are saved in this browser's local storage, so they're still there next time you visit — nothing is sent to a server or shared across devices.
Everything runs locally in your browser.
How this world clock stays accurate ?
Each city's time on this world clock comes straight from your browser reading that city's correct local time. Every city on your list is always consistent with the others as a result. If it's 9 AM in New York, London correctly shows whatever time it actually is there too. Your saved city list stays on this device. It's ready again next time you visit, with no account needed. If you only need a single city instead of a full list, our clock page can help. It shows just your device's local time, full-screen.
Where time zones actually came from ?
Why the gap between cities isn't always a whole number of hours ?
Most places are a whole number of hours apart, but not all. A handful of regions sit at a 30 or 45-minute offset instead of a full hour. That's just how their local time is defined. This clock handles it exactly the same way as any other city. The correct local time simply appears, with nothing to configure.
Why the time difference between two cities can shift with the seasons ?
Two cities can be a fixed number of hours apart for most of the year. Then the gap briefly shifts by an hour, because countries change their clocks on different dates. Some places don't observe daylight saving at all. Each city card here always shows the real current local time. It's never a fixed number you'd have to remember to adjust. Because of that, these seasonal shifts take care of themselves.
Finding a meeting time across time zones
The easiest way to plan across spread-out time zones is keeping a short list of your collaborators' actual cities. That beats trying to hold every time difference in your head. Add each person's city here. A shared meeting window becomes something you can see at a glance, instead of something you calculate.
Why a city sometimes shows "Tomorrow" or "Yesterday" ?
The world is divided into time zones that add up to a full day. That happens as you travel all the way around the globe. Because of that, some cities are a calendar day ahead of or behind you. That's true even when the time difference itself is small. When that happens, a "Tomorrow" or "Yesterday" badge appears next to the city. That keeps the comparison clear at a glance.
How the browser world clock compares
| This browser world clock | Phone world clock app | Physical multi-zone wall clock | |
|---|---|---|---|
| Install required? | No — opens in browser | Pre-installed on most phones | Purchase, one face per zone |
| Cities trackable at once | Unlimited — add or remove freely | Usually capped around 5–10 | Fixed at purchase |
| Automatic DST handling per city | Yes | Yes | No — manual adjustment |
| Saves your list between visits | Yes, in the browser | Yes, on the device | N/A — always visible |
| Shows date and day offset (yesterday/tomorrow) | Yes | Sometimes | No |
| Cost | Free | Free (built-in) | One-time purchase per face |
Frequently asked questions
How many cities can I add?
Add as many as you like from our list of major world cities — there's no fixed limit. Your list is remembered on this device, so it's ready again next time you open the page.
Why does a city show a "Tomorrow" or "Yesterday" badge?
When the time difference crosses midnight, that city's calendar date is a day ahead of or behind your device's date. The badge makes that instantly clear so you don't schedule a call for the wrong day.
Is the time zone data accurate for daylight saving time?
Yes. We use each city's official IANA time zone, so DST transitions are applied automatically and correctly on the date they take effect in that region — no manual adjustment needed.
Can I remove a city from my list?
Yes — click the remove icon next to any city to take it off your list, then add a different one.
Does this work offline or need an account?
No account is needed, and once the page has loaded it keeps ticking with no network connection required. Your city list is stored only in your browser.
Other time tools
All free, all browser-based. One tap away.
Alarm
One-time or recurring alarm with gentle wake.
Timer
Count down from any duration. Keyboard-friendly.
Stopwatch
Centi-second precision with lap splits.
Countdown
Count down to any future date or event.
Clock
Fullscreen analog or digital clock.
Date Calculator
Find the days between two dates, or add/subtract time.
Age Calculator
Exact age in years, months and days from a birthdate.
Pomodoro
Focus blocks with auto-cycle and tasks.