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Cron Expression Decoder

Translate a cron expression into plain English, field by field.

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RAW INPUT
DECODED

Output appears here as you type — decoded on your device.

Input is processed on your device. Nothing you paste is sent anywhere.

What is the Cron Expression Decoder?

A cron expression decoder translates the five space-separated fields of a crontab schedule — minute, hour, day of month, month and day of week — into a plain-English description of when the job actually runs.

A cron expression is terse by design: five fields, each accepting a value, a range (9-17), a list (1,3,5), a step (*/5) or a wildcard. Once you combine them the meaning stops being obvious, and a schedule that reads fine is often not what the author intended.

The classic mistake is 0 0 * * 1-5 versus 0 0 1-5 * *: the first runs at midnight on weekdays, the second at midnight on the first five days of every month. The other is the day-of-month / day-of-week interaction — when both are restricted, cron runs the job if either matches, not both, so 0 0 1 * 1 fires on the first of the month and on every Monday.

Extensions vary by implementation. Vixie cron accepts @daily and @reboot; Quartz adds a seconds field at the front and a year field at the end; Kubernetes CronJob follows standard five-field syntax and runs in UTC unless a time zone is set. Reading the decoded description is faster and safer than reasoning it out.

Cron Expression Decoder at a glance

Fields
minute hour day-of-month month day-of-week
Ranges
0–59 · 0–23 · 1–31 · 1–12 · 0–6 (Sunday = 0)
Step syntax
*/5 means every 5 units of that field
DOM + DOW
If both are restricted, either match triggers the job

How to use the Cron Expression Decoder

  1. 1Paste your cron expression — five fields separated by spaces.
  2. 2Read the plain-English description and the per-field breakdown.
  3. 3Check the time zone your scheduler uses; cron does not assume UTC everywhere.

When you would reach for it

  • Confirming a crontab line does what the comment above it claims.
  • Reviewing a Kubernetes CronJob schedule before deploying it.
  • Auditing inherited scheduled jobs whose intent is no longer documented.

Cron Expression Decoder — frequently asked questions

Last reviewed · questions or corrections: contact@decoder.tools