Cron Expression Decoder
Translate a cron expression into plain English, field by field.
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
- 1Paste your cron expression — five fields separated by spaces.
- 2Read the plain-English description and the per-field breakdown.
- 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