ToolsEveryday

Timestamps & cron

Convert a Unix timestamp or a date between formats and time zones. Paste a cron schedule to see what it means and exactly when it will run next, clock changes included.

Runs entirely in your browser

Timestamp

Now

Cron schedule

Cron expression

Five fields: minute, hour, day of month, month, day of week. Six fields put seconds first. Shortcuts like @daily work, and so does a whole crontab line: the command is ignored.

Time zone the schedule runs in

Show

Starting from

Leave empty for now, or enter a date and time (read in the schedule's time zone) to see runs around a clock change.

How this works

Everything happens in this page's JavaScript, on your device. Nothing is sent to abbott.cloud or anywhere else, so the request log below stays empty.
Numbers are Unix time: the count since 00:00:00 UTC on 1 January 1970, ignoring leap seconds (POSIX). Unless you choose a unit, it's worked out from the number's size: under 10¹¹ is seconds, then milliseconds, microseconds and nanoseconds, each covering the years 1973 to about 5138.
Time zone rules come from your browser's own copy of the IANA time zone database, through the Intl API, so they're as up to date as your browser.
For cron, the page steps through the calendar in the schedule's time zone, matches each field, and turns every matching clock time into a real moment.

Clock changes: run times follow cronie (the cron on Fedora, Red Hat and others, built on Vixie cron). When clocks go forward, a fixed-time job due in the skipped hour runs straight after the change, and a job with * in its minute or hour field skips that hour. When clocks go back, a fixed-time job runs once and a * job runs in both copies of the hour. Changes of 3 hours or more aren't caught up. With CRON_TZ= in the line, cronie skips missing times and runs repeated ones twice.

What's kept: nothing. What you type is copied into this page's address so you can bookmark or share the result, but it isn't stored.

Limitations:

Dates use the Gregorian calendar, extended back before 1582, and old dates use whatever local time your browser's data has for them.
Other schedulers, such as systemd timers, Kubernetes CronJobs and cloud schedulers, can handle clock changes differently.
Quartz's year field and AWS's six-field format aren't supported.

Code: time.js (this page), lib/timefmt.js (parsing, time zones and formats), lib/cron.js (cron parsing, descriptions and run times).