Cron Expression Parser Online — Decode Cron & See Next Run Times
Paste any cron expression and decode it into a plain-English description plus the next several scheduled run times in your local timezone. Use it to audit existing crontabs, debug a scheduler that fires at the wrong moment, or learn cron syntax by example. The parser runs locally in your browser.
Features
Human-readable description
Translate `0 9 * * 1-5` into "At 09:00 AM, Monday through Friday" instantly.
Next run times
See the next 5–10 firing times in your local timezone — verify the schedule before trusting it.
Error explanations
Invalid expressions get a precise error message pointing to the field at fault.
No network calls
Expressions are parsed locally — paste sensitive scheduler config without worry.
How to parse a cron expression online
Decode any cron expression in two steps.
- Paste your expressionDrop a five-field cron expression (e.g. `*/15 * * * *`) into the input.
- Read the descriptionThe plain-English sentence updates as you type. Invalid expressions display a precise error.
- Inspect upcoming runsBelow the description, the next scheduled run times are listed in your timezone.
Examples
Decode a typical schedule
Input
*/15 9-17 * * 1-5
Output
At every 15th minute past every hour from 9 through 17, Monday through Friday. Next runs: 2026-05-21 09:00 2026-05-21 09:15 2026-05-21 09:30
Decode a monthly schedule
Input
0 0 1 * *
Output
At 12:00 AM, on day 1 of the month. Next runs: 2026-06-01 00:00 2026-07-01 00:00 2026-08-01 00:00
Frequently Asked Questions
- What cron format does this support?
- Standard Unix-style five-field cron (minute, hour, day-of-month, month, day-of-week). Six-field Quartz expressions are partially supported.
- Why does my expression show different next-run times than my server?
- Timezones. The preview uses your browser's local timezone. Servers often run in UTC, so a schedule that says "9:00" in the description may fire at a different wall-clock time on the server.
- Are seconds supported?
- Standard Unix cron does not support seconds. If your expression has 6 fields with a leading seconds field, switch to Quartz mode.
- What does `L`, `W`, or `#` mean in cron?
- `L` = last (day of month or week), `W` = nearest weekday, `#` = nth occurrence of a weekday in the month. These are Quartz extensions and are not part of standard Unix cron.
- Can the parser show past run times?
- Not currently. The next-run list looks forward. For historical "did this fire" debugging, check your scheduler's execution logs.