glunty Cron Next Run Times Calculator
Enter a cron expression and preview its upcoming run times. Fully client-side, nothing uploaded.
- Runs in your browser
- No sign-up
- No watermark
- No installs
What this tool does
A cron expression says when a scheduled job should run, but it does not tell you the actual dates and times it will fire. This tool takes a standard 5-field cron expression and computes the next several run times, reading the clock the moment you press the button. It walks forward one minute at a time from the current local time and lists each upcoming match as a readable date and time. Everything runs in your browser; your cron expression never leaves the page.
How to use it
Type or paste a cron expression into the box. The five fields, in order, are minute
(0 to 59), hour (0 to 23), day-of-month (1 to 31), month (1 to 12 or JAN to DEC), and
day-of-week (0 to 7 where 0 and 7 are Sunday, or SUN to SAT). Pick how many upcoming
runs you want (up to 10) and press Show next runs. Example:
0 0 * * * lists the next few midnights, and */15 * * * *
lists times fifteen minutes apart. The listed times use your local time zone.
Common use cases
- Sanity-checking that a new cron job will fire when you expect before you deploy it.
- Answering "when does this actually run next?" for a schedule someone else wrote.
- Confirming a "0 0 * * *" is daily midnight, not hourly, by seeing the real dates.
- Spotting an impossible schedule (like February 30) that would never fire at all.
- Documenting the next occurrences of a job in a runbook or change ticket.
Common pitfalls
- Day-of-month vs day-of-week. When both fields are restricted
(neither is
*), standard cron fires when either matches, not both. This tool follows that OR rule, so you may see more days than you intended. - Time zone. A cron expression carries no time zone of its own; it runs in the time zone of the machine it lives on. This preview uses your browser local zone, so if your server runs in UTC the real fire times will differ.
- Impossible expressions. Combinations like
0 0 30 2 *never match a real date. The search is capped at about two years, after which the tool reports that no runs were found instead of hanging.
Frequently asked questions
- Which time zone are the run times shown in?
- The upcoming run times are computed and displayed in your browser local time zone, the same zone your operating system reports. A real cron daemon runs in the time zone of the server it lives on, which is often UTC. If your server is not in your local zone, the actual fire times will be shifted. Use the time zone converter to translate a run time from one zone to another.
- How are the next run times calculated?
- The tool starts at the next whole minute after the current time and steps forward one minute at a time, checking each minute against the parsed cron fields. Every minute that matches is added to the list until it has collected the number you asked for. The search is capped at about two years, so an impossible expression stops instead of looping forever.
- What does the day-of-month OR day-of-week rule mean?
- When both the day-of-month field and the day-of-week field are restricted (neither is a star), standard cron fires when EITHER field matches, not only when both match. So 0 0 1 * 1 runs on the 1st of every month AND on every Monday. This tool follows that OR rule, which is why a schedule can list more days than you might first expect. To require both conditions, restrict one field and check the other inside your job.
- Why do I see no upcoming runs?
- Some cron expressions can never match a real calendar date, for example 0 0 30 2 * asks for the 30th of February. When nothing matches within the two-year search window, the tool reports that no runs were found rather than freezing. Re-check the day-of-month and month combination if you expected results.
- What cron syntax does this support?
- It handles the standard 5 fields: minute, hour, day-of-month, month, and day-of-week. Each field accepts a star, single values, lists such as 1,15,30, ranges such as 1-5, and steps such as */15 or 1-30/5. Month names (JAN to DEC) and day names (SUN to SAT) are accepted, and both 0 and 7 mean Sunday. It does not handle seconds, @daily style aliases, or special names like L and W.
- Does this send my cron expression anywhere?
- No. Parsing and all date math run entirely in your browser with plain JavaScript. Nothing is uploaded and there are no network requests while the tool works. You can confirm this by opening DevTools and watching the Network tab while you preview a schedule.
Cite this tool
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Citations use 2026 as the publication year. Access date is left as a fillable placeholder where the citation style expects one.