Your local time
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 current time in major cities across every continent, with dates and UTC offsets.
Time Zone Converter
Convert any time between two zones — daylight saving is handled automatically.
Date Calculator
Days, weeks, months, and years between any two dates, plus add-or-subtract days.
Age Calculator
Exact age in years, months, and days — and how long until the next birthday.
Countdown Timer
Count down to any date and time, and share the countdown with a link.
Unix Timestamp
Turn epoch seconds into a readable date and back — with the current timestamp live.
Week Number
Today's ISO 8601 week number, how it's calculated, and a full-year week table.
Stopwatch
A big, precise stopwatch with lap times that stays correct even in a background tab.
Born on What Day
The day of the week for any date of birth — and your birthday's weekday this year.
Age Difference
The exact age gap in years, months, and days between two people or two dates.
Days Until Christmas
How many days remain until the next 25 December, with the exact date displayed.
Meeting Planner
Add up to five cities and find the hours that overlap for everyone.
Embed Widget
A live clock you can drop into your own site — pick a city, theme, and size.
Business Days
Count working days between two dates, or add and subtract them, skipping weekends and holidays.
Weather
Current conditions, an hourly outlook, and a 7-day forecast for any city or your location.
Bedtime Calculator
Find the best time to sleep or wake up based on 90-minute sleep cycles.
Busy Score
Add up today's commitments and get a 0-100 score for how packed your day is.
Daily Time Audit
See exactly how your 24 hours split across sleep, work, screen time, and more.
Habit Clock
Run a short timed habit session and keep a daily streak going.
Routine Builder
Plan your day block by block on a visual timeline and spot overlaps early.
Flight Arrival Calculator
Enter your departure time and flight length to get the local arrival time, DST and date-line aware.
Time Puzzle
A daily guess-the-city-time game with a streak to keep going.
Daily Fact
A new time zone fact every day, worth a quick look each morning.
Daily World Briefing
Hottest and coldest cities, longest and shortest day, tonight's moon, and upcoming DST changes.
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.
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.