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Cron Expression Parser

Split a standard five-field cron expression into minute, hour, day-of-month, month, and weekday explanations.

Exactly five cron fields Wildcards, steps, ranges, and lists described Readable field-by-field output Common daily and weekday summaries
Parses standard five-field cron syntax. Quartz, Jenkins, AWS/EventBridge, seconds fields, and platform-specific extensions may use different rules.
INPUT Cron expression *
0 chars0 words0 lines
Ctrl / ⌘ + Enter
Cron explanation
About the tool

What Cron Expression Parser does

Cron Expression Parser separates a standard five-field cron expression into minute, hour, day-of-month, month, and day-of-week components. It describes wildcards, step values, ranges, lists, and plain numeric values so a compact schedule is easier to review.

For example, */15 9-17 * * 1-5 means a minute step of 15, hours 9 through 17, every day of the month, every month, and weekdays 1 through 5. The exact moments and timezone still depend on the scheduler that executes the expression.

This parser is intentionally limited to five fields. Quartz, Jenkins, AWS EventBridge, systemd timers, and other platforms may use different field counts, special tokens, or day-of-week numbering.

Five-field cron expression parser showing minute hour day month and weekday components
Read each five-field cron component separately before deploying the schedule.

How to use

  1. Paste the expression. Use minute, hour, day of month, month, and day of week in that order.
  2. Remove command text. Paste only the schedule fields, not the shell command from a crontab line.
  3. Run the parser. The output describes every field and recognizes a small number of common patterns.
  4. Check platform rules. Verify ranges, names, special characters, and day-of-week numbering in the destination documentation.
  5. Confirm timezone behavior. Cron expressions normally contain no timezone, so the scheduler configuration determines when they run.
Built for the task

Why use Cron Expression Parser?

Focused controls, predictable output, and a workflow designed around this exact transformation.

01

Field-by-field explanation

Review minute, hour, day-of-month, month, and weekday independently.

02

Common syntax hints

See readable descriptions for wildcards, steps, numeric ranges, and comma-separated lists.

03

Source remains visible

Compare the original expression with the explanation without rewriting it.

04

Dialect warnings

The guide distinguishes standard five-field cron from platform-specific variants.

Useful answers

Questions about Cron Expression Parser

Practical details about input, output, privacy, limits, and the best way to use this tool.

01 What order do the five cron fields use?

The order is minute, hour, day of month, month, and day of week.

02 Does this parser support a seconds field?

No. It expects exactly five fields. Six- or seven-field dialects must be checked with their platform documentation.

03 What does an asterisk mean?

An asterisk means every allowed value for that field, subject to the scheduler implementation.

04 What does */15 mean?

It is a step expression meaning every 15 values in that field. In the minute field, it commonly selects minutes 0, 15, 30, and 45.

05 Which timezone does cron use?

The expression itself usually carries no timezone. The operating system, container, control panel, or managed scheduler supplies it.

06 Are weekday numbers universal?

No. Many implementations use 0 or 7 for Sunday and 1 for Monday, but platform rules differ.

07 Does parsing prove the schedule is valid?

No. The tool explains five tokens; the destination scheduler remains authoritative for supported ranges and extensions.

08 Can I paste a complete crontab line?

Paste only the five schedule fields. Do not include the command, environment assignment, or username column.

The five fields in a cron expression

A standard cron schedule places five whitespace-separated fields before the command. The minute field normally selects 0–59, the hour field 0–23, the day-of-month field 1–31, the month field 1–12, and the day-of-week field a platform-defined representation of Sunday through Saturday.

The parser labels these positions but does not know the command, server timezone, missed-run policy, or scheduler extensions. Keep those operational settings beside the expression in project documentation.

Wildcards, steps, ranges, and lists

* selects all allowed values. A step such as */10 selects every tenth value. A range such as 9-17 selects the values from 9 through 17, while a list such as 1,3,5 selects specific values. Combinations and named months or weekdays may be supported, but the exact grammar belongs to the destination implementation.

A readable explanation can still hide an invalid range. For example, a day-of-month value may be impossible for a particular month. Test real execution dates when calendar behavior matters.

Timezone and daylight saving time

Five-field cron syntax does not normally state a timezone. A schedule such as 0 9 * * * means 09:00 in the timezone used by the scheduler. Containers, hosting panels, WordPress jobs, CI services, and managed clouds can use different defaults.

Daylight-saving transitions may skip a local time or cause it to occur twice. For billing, notifications, backups, or data imports, document whether the job must follow local civil time or a fixed UTC time.

Standard cron and platform-specific dialects

Quartz often adds seconds and optional year fields. AWS EventBridge uses its own six-field expression and special rules. Jenkins supports hashed scheduling tokens. Some Unix implementations accept names such as MON or JAN, while others have narrower syntax.

Do not convert between these systems by field count alone. Compare every token with the official documentation for the exact runtime and version.

Cron deployment checklist

  • Confirm the field count and scheduler dialect.
  • Verify the configured timezone.
  • Check day-of-month and day-of-week interaction.
  • Test month-end and daylight-saving cases.
  • Define overlap, retry, timeout, and missed-run behavior.
  • Monitor at least the first production executions.

Related Trexmi tools

Create a schedule with Cron Expression Generator or convert exact instants with Timestamp Converter.

Authoritative reference

For the traditional utility and crontab model, review the POSIX crontab specification. Platform documentation remains authoritative for extensions.