Cron Expression Explainer
Paste a five-field Unix crontab line, or six fields with seconds first. See which calendar fields match and the next dozen fire times on this device.
Tool input stays in your browserDid you know · Encoding
Base64 padding uses = to round the output to a multiple of four characters.
Five fields (minute hour day month weekday) or six with seconds first. Next runs use this browser's local timezone, and refresh every second.
Schedule
you editPick a preset or write a cron expression.
Next runs
read onlyComputed in this browser's local timezone.
Reading this browser's timezone…
Unix fields, local clock
Standard crontab order is minute, hour, day-of-month, month, day-of-week. A sixth field on the left is seconds. Lists, ranges, and steps (*/15, 1-5) work. Month and weekday names such as MON and JAN are accepted. Sunday is 0 or 7.
When both day-of-month and day-of-week are restricted, a date matches if either field matches — classic Vixie cron, not Quartz AND. ? is treated as *. Macros such as @daily are not expanded. Next runs are computed in this browser's timezone, not UTC, unless the device is set to UTC.
Why it stays private
Job names and production cadences often leak environment shape. Parsing and the next-run walk run locally. Nothing is sent.
Cron FAQ
Cron expression meaning, next run time, five vs six fields, and weekday vs day-of-month.
What is a cron expression?
A cron expression is a compact schedule used by cron daemons: five fields for minute, hour, day-of-month, month, and weekday. This explainer also accepts a sixth seconds field on the left.
How do I see the next cron run time?
Paste the expression. The table lists the next twelve matching instants in this browser’s local timezone, plus ISO 8601. From now refreshes the origin time.
Why do day-of-month and weekday both match?
When both fields are restricted, Unix cron fires if either matches (OR), not only when both match. That is Vixie behaviour, not Quartz.
Are @daily and Quartz cron supported?
Macros such as @daily are not expanded. Quartz 7-field expressions and L/W/# tokens are not implemented. Stick to five- or six-field Unix cron.
Is the cron parser private?
Yes. Explanation and next-run calculation run locally. Production schedules are not uploaded.