Exact local time now
Check the time in another city
The time tools you need for your daily workflow
A tool for every minute
Free utilities for everyday time questions — what time it is somewhere else, how many days until a deadline, exactly how old someone is, what a Unix timestamp means, or what the weather's doing right now.
Local Zone Time
Live time in major cities on every continent, plus a 110-city directory with local weather.
Time Zone Converter
Convert any time between two zones — daylight saving is handled automatically.
Meeting Planner
Add up to five cities and find the hours that overlap for everyone.
Flight Arrival Calculator
Enter your departure time and flight length to get the local arrival time, DST and date-line aware.
Date Calculator
Days, weeks, months, and years between any two dates, plus add-or-subtract days.
Business Days
Count working days between two dates, or add and subtract them, skipping weekends and holidays.
Age Calculator
Exact age in years, months, and days — and how long until the next birthday.
Age Difference
The exact age gap in years, months, and days between two people or two dates.
Countdown Timer
Count down to any date and time, and share the countdown with a link.
Days Until Christmas
How many days remain until the next 25 December, with the exact date displayed.
Week Number
Today's ISO 8601 week number, how it's calculated, and a full-year week table.
Unix Timestamp
Turn epoch seconds into a readable date and back — with the current timestamp live.
Time around the world
Current time in popular cities
Live local time, UTC offset and daylight saving details for each city.
- New York
- London
- Tokyo
- Los Angeles
- Toronto
- Paris
- Dubai
- Sydney
- Singapore
- Chicago
- Boston
- Denver
- Mexico City
- Santo Domingo
- Buenos Aires
- São Paulo
- Madrid
- Milan
- Berlin
- Istanbul
- Moscow
- Cairo
- Johannesburg
- Mumbai
- Bangkok
- Shanghai
- Hong Kong
- Seoul
- Auckland
Time difference between cities
Two cities side by side: how many hours apart they are right now, and how daylight saving changes the gap.
- New York vs London
- Los Angeles vs Tokyo
- New York vs Toronto
- Milan vs New York
- Tokyo vs Seoul
- New York vs Los Angeles
- Sydney vs London
- Paris vs New York
- Chicago vs Tokyo
- Toronto vs London
- London vs Dubai
- Mumbai vs New York
- Singapore vs London
- Mexico City vs New York
- Santo Domingo vs New York
- Buenos Aires vs New York
- Dubai vs Mumbai
- Dubai vs Istanbul
- Cairo vs London
- Shanghai vs London
- Hong Kong vs Singapore
- Bangkok vs Sydney
Why another time site?
Most time websites bury a thirty-second answer under pop-ups, autoplaying video, and pages of boilerplate. WatchTime Online takes the opposite approach. Each tool lives on its own fast, single-purpose page. The calculation runs in your browser, nothing you type is sent to a server, and the explanation under each tool tells you how the math actually works — so you can sanity-check the result instead of taking it on faith.
That last part matters more than it sounds. Date arithmetic is full of traps: months have four different lengths, leap years skip most century years but not all of them, and daylight saving time means one day a year has 23 hours and another has 25. A calculator that hides its method can quietly get these wrong. Every page here documents the rules it follows — ISO 8601 week numbering, calendar-month age counting, IANA time zone data — so the results are reproducible anywhere.
Where a rule needs more room than a tool page allows, there's a longer write-up in the guides: how time zones actually work, why daylight saving time breaks schedules, the leap year rule and its exceptions, and how ISO week numbering decides which week is week 1. Newer guides cover reading flight times across time zones, scheduling meetings across cities, counting days between dates, how age is calculated, Unix time and the International Date Line.
Who runs WatchTime Online
The site is built and maintained by Milton S., an independent web designer and developer based in Massachusetts who also does graphic design. It started from a small annoyance — every time-and-date tool I tried buried a thirty-second answer under pop-ups and filler — so I built the versions I wanted to use myself. Every tool is written and tested here, and corrections are welcome: the about page has the full story and the contact page reaches me directly.
Common questions
Is the clock on this page accurate?
The clock reads your own device's system time, which on any modern phone or computer is synchronized over the internet (via NTP) and is typically accurate to well under a second. If the clock looks wrong, your device's time zone or clock settings are the place to fix it.
Do the tools store what I enter?
No. Every calculator runs entirely in your browser using JavaScript. Dates, birthdays, and timestamps you type are never transmitted or stored. See the privacy policy for details on the analytics and advertising cookies the site itself uses.
Which time zone database do the tools use?
The world clock and zone converter rely on your browser's built-in implementation of the IANA time zone database — the same reference data used by operating systems worldwide. That means daylight saving rules and historical offset changes are handled by data that your browser vendor keeps up to date.
Can I use these tools on my phone?
Yes. Every page is a lightweight, responsive page with no app to install. Bookmark the tool you use most; it will load in under a second on a typical connection.