AWS Cron Expression Helper
Build and explain AWS EventBridge/CloudWatch-style cron expressions, which use a different 6-field format from standard Linux cron.
Build an AWS-style cron expression for an EventBridge or CloudWatch scheduled rule - this format has real differences from standard Linux cron.
AWS cron expressions have 6 fields (adding Year) and require exactly one of Day-of-Month / Day-of-Week to be ? - this tool enforces that automatically.
For a standard 5-field Linux/Unix cron expression instead (crontab, systemd timers), see the Cron Expression Builder.
How Is AWS Cron Different from Linux Cron?
AWS EventBridge/CloudWatch cron expressions use 6 fields instead of Linux cron's 5 - adding a Year field - in the order minute hour day-of-month month day-of-week year. Critically, AWS requires exactly one of day-of-month or day-of-week to be a ? (question mark), since specifying both as a value simultaneously isn't allowed.
Why Use This Tool?
Pasting a standard 5-field Linux cron expression into an EventBridge rule will simply be rejected - the extra Year field and the day-of-month/day-of-week ? requirement are AWS-specific rules this tool applies automatically.
How to Use It
- Build your schedule using the minute/hour/day fields - the tool handles the day-of-month/day-of-week
?requirement for you. - Review the generated 6-field expression and its plain-English explanation.
- Copy it into your EventBridge rule's schedule expression (wrapped as
cron(...)).
Limitations
This covers AWS's cron() schedule expression syntax specifically - EventBridge also supports a simpler rate() expression (e.g. rate(5 minutes)) for basic fixed-interval schedules, which is a separate, simpler syntax not generated here.