Every minute
Useful for quick jobs, but expensive if the task is heavier than expected.
* * * * * Dates & Time 7 min read 2026-03-15
Cron Expression Explained with Practical Examples
Learn how cron syntax works, read common schedules, and verify the next run times before deploying jobs.
Intro
Cron is compact, powerful, and easy to misread. A single expression can silently run too often, not often enough, or at the wrong local time.
The safe workflow is to translate the expression into plain language and inspect upcoming run times before shipping it.
What is it?
A cron expression is a compact schedule format used to define recurring execution times for jobs and automation.
Depending on the environment, cron strings can have five fields, six fields, or special syntax extensions.
Why it matters
- Production jobs often fail because the schedule itself was misunderstood.
- Small syntax mistakes can create outages, duplicate work, or missed cleanups.
- Readable schedule previews reduce deployment risk significantly.
Examples
Every day at midnight
A common batch-processing schedule.
0 0 * * *Common mistakes
- Confusing day-of-month and day-of-week fields.
- Assuming all cron implementations support the same syntax.
- Forgetting that timezone configuration can change the effective schedule.
- Deploying a cron string without previewing the next run dates.
Use the tool
Ready to try Cron Parser?
Preview upcoming runs for a cron expression.
Open full tool pageFAQ
Why does a valid cron expression still run at the wrong time?
The syntax may be correct but evaluated in a different timezone than expected, or by an engine with slightly different cron rules.
Should I trust memory for cron syntax?
No. Preview the schedule every time. Cron mistakes are cheap to check and expensive to debug later.