Crontab Explainer
Paste any standard 5-field cron expression — minute, hour, day of month, month, day of week — and read a plain sentence describing its schedule, including comma lists, ranges, and step values.
Overview
Cron expressions are compact by design, which makes an unfamiliar one hard to read at a glance — especially once ranges (`1-5`), lists (`1,15,30`), and steps (`*/15`) are combined in the same field. This tool parses the expression field by field and explains it in a sentence, so you can confirm what an existing crontab entry, CI schedule trigger, or inherited script actually does before you rely on it.
This is a parser, not a builder — it explains an expression you already have rather than helping you construct one from scratch. Use the Cron Expression Generator for that direction instead.
Examples
A simple daily schedule
0 9 * * *
Runs at 09:00, every day.
A step value with a weekday range
*/15 9-17 * * 1-5
Runs every 15 minutes, during hour 9 through 17, on Monday through Friday.
How It Works
- Paste a standard 5-field cron expression (minute, hour, day of month, month, day of week).
- Click Explain.
- Read the plain-English description of when the schedule fires.
Use Cases
Reviewing an inherited crontab
Understand exactly what a schedule someone else wrote actually does before changing or removing it.
Double-checking a CI/CD schedule trigger
Confirm a GitHub Actions `schedule:` cron or similar scheduler config fires when you expect.
Tips
- When both Day of month and Day of week are restricted to specific values at the same time, standard cron treats them as OR, not AND — the description spells this out explicitly whenever it applies.
- Step values (`*/15`) and ranges (`1-5`) can be combined in the same field (`1-30/5`) — this tool explains that combination as a single clause.
FAQ
No. The expression is parsed and explained entirely in your browser.
No, this explains standard 5-field cron (minute, hour, day of month, month, day of week), the format used by crontab and most schedulers.
Asterisks (every value), specific numbers, comma-separated lists (1,15,30), ranges (1-5), and step values (*/15 or 1-30/5), including combinations of the above within one field.
Use the Cron Expression Generator for that — it builds a valid expression from dropdowns instead of parsing free text.