Clocks, Timers and Cron Schedules
These tools tell, measure and schedule time: a world clock for comparing cities, a stopwatch and a countdown timer with fullscreen displays, an analog or digital wall clock, and a cron expression validator that explains a schedule in plain English and lists its next five runs. Remote teams, presenters, teachers, coaches and developers setting up scheduled jobs use them.
5 free tools · no sign-up · no ads
All Time Utilities (5)
World Clock
View time in multiple timezonesStopwatch
Start, pause and reset stopwatch with a fullscreen displayCountdown Timer
Large screen countdown timer perfect for events, presentations, and meetingsOnline Clock
Beautiful analog and digital clock with fullscreen modeCron Expression Validator
Validate and explain cron expressions
Which tool do I need?
See the time in Tokyo and New York before booking a call
Add cities to the world clock and drag them into order. Each tile shows its live time and date.
Time a talk or exam on a big screen
Set a countdown and switch to fullscreen, or show the fullscreen clock so everyone can see the time.
Measure how long a task takes
Start, pause and reset the stopwatch, which reads to hundredths of a second.
Check a crontab line before deploying it
Paste the five-field expression to see a plain-English description and the next five run times.
About Time Utilities
The four clocks and timers are display tools. Put the countdown on a projector for a workshop time box, run the stopwatch for a timed exercise, or leave the online clock fullscreen on a spare monitor. The world clock answers the scheduling question before a call across time zones. The cron validator belongs to the same theme from a developer's side: it shows when a crontab line or CI schedule will actually fire. For converting Unix timestamps, see Converters, and for date arithmetic and business-day counts, see Calculation Tools.
Everything runs in your browser, which sets the limits. Timers stop if you close or reload the tab, and a sleeping computer delays alerts. The stopwatch measures from timestamps, so it stays accurate in a background tab. The countdown makes no sound of its own beyond a system notification. The cron validator shows next runs in your browser's time zone, while most servers and GitHub Actions run cron in UTC.
Guides
- Stopwatches, Countdown Timers and Clocks in the Browser: Why Time DriftsWhy setInterval timers run slow in background tabs, how timestamp-based stopwatches and deadline-based countdowns fix it, and how world clocks get DST right.
- Time Zones for Developers: Offsets, DST and IANA Zone NamesA UTC offset is not a time zone. How the IANA database works, what happens to 02:30 on a DST night, and the rules that keep scheduling code out of trouble.
- Crontab Syntax & Cron Expressions: The Complete GuideA visual cheat sheet plus real-world examples for reading, writing, and debugging cron expressions — with an interactive validator to test them instantly.
Frequently asked questions
Which time zone does a cron schedule run in?
The time zone of the machine or service running it. Linux cron uses the server's zone, and GitHub Actions schedules run in UTC unless you set a time zone, so check which applies before writing the expression.
Why do meeting times shift around daylight saving changes?
Because regions change their clocks on different dates, and some never do. For a few weeks each spring and autumn the gap between two cities can be an hour different from usual.
Can I leave a browser clock running on a wall display?
Yes. Open the clock in fullscreen and set the operating system not to sleep or dim the screen, since browsers may let a static page go dark.
Is a browser stopwatch accurate enough for timing races?
For casual timing, yes: it measures from timestamps and reads to hundredths. Human reaction time on the buttons is a bigger error than the clock, so use dedicated equipment for official results.