Cron → Natural Language

Someone left 30 4 * * 6 in the crontab and then left the company. Before you touch that server, you need to know whether it fires on Saturday or on Sunday. Paste the five fields here and the expression turns into a sentence you can read at a glance. Worth knowing up front: the sentence comes out in Portuguese, because the weekday and month names in this tool are only defined in that language.

The day-of-week field uses 0 for Sunday and 6 for Saturday, which is where people coming from another convention slip. There is a second trap almost no cron translator mentions: when you fill in both day-of-month and day-of-week, Linux cron runs on either match, not on both at once. So 0 0 13 * 5 fires on every 13th and also on every Friday. The generated sentence lists both pieces separated by a comma, which can read like a single condition.

It handles the asterisk, ranges like 1-5, lists like 1,3,5 and steps like */15. It does not handle names (MON and JAN come out exactly as typed), shortcuts like @daily, a step inside a range (1-5/2 shows up raw) or the sixth seconds field used by Quartz and Spring. It does no range checking either: 99 99 * * * happily becomes 99:99. And it translates rather than simulates, so it never lists upcoming runs. Everything happens in your browser.