Cron Expression Parser & Builder
What is Cron Expression Parser & Builder
A cron expression is a five-field string used by Unix-like schedulers (and tools like crontab, Kubernetes CronJobs, and CI pipelines) to define when a job should run: minute, hour, day of month, month, and day of week. This tool works both ways. Paste an expression and it translates the cryptic syntax into a plain-English sentence and lists the next five run times in UTC. Or use the field builder to assemble a valid expression from scratch — the two views stay in sync as you edit either side.
How to use
- Type or paste a cron expression such as 0 9 * * 1-5 into the input field.
- Read the plain-English meaning and check the next five scheduled run times below it.
- Edit any of the five builder fields (minute, hour, day, month, weekday) to construct an expression piece by piece.
- Click an example chip to load a common schedule, then adjust it to fit your needs.
When to use it
Wrote 0 3 * * * for a nightly database backup and want to be sure it does what you think? Paste it in and you will see it reads "at 03:00", with the next runs landing at 3 AM each day. Need to skip weekends later? Change the last field to 1-5 and the preview updates to show runs only Monday through Friday.
Frequently asked questions
What do the five fields in a cron expression mean?
From left to right: minute (0–59), hour (0–23), day of the month (1–31), month (1–12), and day of the week (0–6, where 0 and 7 both mean Sunday). An asterisk (*) in any field means "every" value for that field.
What do the special characters like * / - and , mean?
An asterisk (*) matches every value. A slash defines a step, so */15 means every 15th value. A hyphen defines a range, so 9-17 means 9 through 17. A comma lists specific values, so 1,15,30. These can be combined, for example 0-30/10.
Which timezone are the next run times shown in?
All calculated run times are shown in UTC. Most cron daemons run in the server's local timezone, so if your server is not on UTC, adjust accordingly. Showing UTC keeps the results unambiguous regardless of where you are.
How are day-of-month and day-of-week combined?
This parser follows standard Vixie-cron rules: if both the day-of-month and day-of-week fields are restricted (not *), a run fires when either one matches. If only one is restricted, only that one needs to match.
Does this support seconds or non-standard cron syntax?
No. This tool handles the classic five-field cron format (minute, hour, day, month, weekday). It does not parse the optional six-field format with a leading seconds column used by some schedulers like Quartz.
Can I share this tool with my inputs pre-filled?
Yes. The URL updates automatically as you type. Copy it from the address bar or use the Share button — anyone who opens the link will see your exact inputs ready to go.
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