Cron Expression Parser (Cron to English)

Cron expressions are compact but hard to read. This parser explains a crontab or Quartz expression in plain English and lists its next run times in the time zone you choose, flagging any run that falls in an hour skipped or repeated by a daylight-saving change. It understands ranges, steps, lists, month and weekday names, the @ macros and the Quartz L, W, # and ? markers, and names the field when something is wrong.

How to use this tool

1. Paste the expression: 5 fields for crontab, or 6–7 for Quartz (seconds first, optional year).
2. Set the start date, time and the time zone the scheduler runs in.
3. Read the English description and the dialect it was read as.
4. Check the next run times and any daylight-saving warnings in the table.

Formula

Crontab fields are minute (0–59), hour (0–23), day of month (1–31), month (1–12 or JAN–DEC) and day of week (0–7, where 0 and 7 are Sunday, or SUN–SAT). Quartz puts seconds first, numbers weekdays 1 (Sunday) to 7 (Saturday), allows a year field, and needs "?" in one day field.

Following Vixie cron, if both day fields are restricted the job runs when either matches; if either starts with "*", both must match. Quartz adds L (last day, or last given weekday as 6L), L-3 (three days before the last), W (nearest weekday) and # (the nth weekday, as 2#2).

Example

30 9 * * 1-5 reads "At 09:30, on Monday through Friday"; from 1 January 2026 (a Thursday) it next runs that same morning. The Quartz expression 0 15 10 ? * 6L runs at 10:15 on the last Friday of each month — 30 January 2026 first.