Cron Expression Parser
Translate a cron expression into plain English and preview its next run times.
Translate a Cron Expression into Plain English
Cron’s five fields are compact but easy to misread, and the cost of a mistake is disproportionate: a job that was meant to run monthly running every minute can take down a database, and one meant to run nightly that silently never fires can go unnoticed for weeks.
This parser expands each field into the exact values it matches, describes the schedule in plain English, and calculates the next five run times against your local clock. Seeing real dates is the fastest way to confirm an expression does what you intended.
Key features
- Plain-English description — the whole schedule in one readable sentence.
- Next five run times — real dates and times, computed from now.
- Field-by-field expansion — every field shown with the exact values it matches.
- Full syntax support — ranges, lists, steps, wildcards and the
@dailystyle shorthands. - Impossible schedules detected — an expression that can never fire is reported rather than looping forever.
- Common presets — one click for hourly, daily, weekday and every-fifteen-minute schedules.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Cron Expression Parser
- Enter a cron expression
Five fields: minute, hour, day of month, month, day of week. Shorthands like <code>@daily</code> are expanded for you. - Read the description
The banner states in plain English exactly when the job runs. - Check the next run times
Five real dates in your local timezone — the quickest sanity check there is. - Review the field breakdown
Each field is expanded to the values it matches, which makes an over-broad wildcard obvious.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Developer |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
What do the five cron fields mean?
In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12) and day of week (0–6, where both 0 and 7 are Sunday). An asterisk means every value for that field.
What does */15 mean?
Every fifteenth value from the start of the range. In the minute field that is minutes 0, 15, 30 and 45 — so four times an hour, not "every 15 minutes from now".
What happens if both day-of-month and day-of-week are set?
In standard Unix cron the job runs when <em>either</em> matches, not both — a frequent and surprising source of extra runs. This parser shows the next run times so the behaviour is visible rather than assumed.
Does cron handle timezones and daylight saving?
Standard cron runs in the server’s local timezone, so a job scheduled at 02:30 may run twice or not at all on clock-change days. The preview here uses your browser’s timezone — check your server’s setting before relying on it.