Cron Expression Parser
Paste a cron expression and get a field-by-field explanation plus the next five run times in your local timezone. Runs in your browser.
Private by construction. The conversion happens in this page's JavaScript. Nothing you paste here leaves your machine, and the tool keeps working with the network unplugged.
Paste any standard five-field crontab expression and get two things: a field-by-field breakdown of what each part means, and the next five times it will actually fire, computed in your local timezone. Steps (*/15), ranges (9-17), lists (1,15), and names (mon-fri, jan) are all supported. The parser also flags cron's most misunderstood rule: when both the day-of-month and day-of-week fields are restricted, standard cron fires when either matches — an OR, not the AND almost everyone expects. Schedules that look right but fire on the wrong days are usually this rule.
Questions this tool gets asked
What do the five fields mean?
In order: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-7, where both 0 and 7 mean Sunday). Each field takes numbers, ranges, lists, steps, or * for every value.
Why does my job run on days I didn't expect?
Almost always the OR rule: if you restrict both day-of-month and day-of-week (say “1 * * 1” hoping for Mondays that are the 1st), standard cron fires on the 1st OR on Mondays. Restrict only one of the two fields, or guard inside the script.
Are the next-run times in my timezone?
Yes - they are computed with your browser's local clock. Remember the server running the actual crontab uses its own timezone, which on most servers is UTC.
Does this support 6-field (seconds) or @daily syntax?
No. Six-field expressions are Quartz/Spring syntax, not crontab, and @daily-style shortcuts vary by implementation. Translate them to five fields (@daily is “0 0 * * *”) and paste that.