EventBridge Cron Expression Validator
Paste an AWS EventBridge schedule expression — cron(…), rate(…) or, for EventBridge Scheduler, at(…) — to validate it, read it in plain English and see the next 5 runs. Scheduled rules run in UTC; for EventBridge Scheduler, pick the schedule's timezone. Switch to Convert for the Unix cron or Quartz version.
Scheduler
Field rules follow the EventBridge scheduled-rule reference (a legacy feature; AWS recommends EventBridge Scheduler).
cron(minute hour day-of-month month day-of-week year) or rate(value unit) — always UTC, Sunday = 1
UTC (fixed for EventBridge rules)
Runs are listed after this time. Empty = now.
✓ Valid for EventBridge rule
At 10:00.
Next 5 runs
| # | Local (UTC) | UTC | DST |
|---|
- ℹ DST: Scheduled rules always run in UTC, so a clock change never skips or repeats a run; the local time of each run moves by an hour instead.
Latest DevOps articles
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A practical reference for cron expressions with common examples, field breakdown, and mistakes to avoid — for Unix cron, GitHub Actions, Kubernetes CronJobs, and AWS EventBridge.
What is an EventBridge cron expression?
Amazon EventBridge schedules accept two formats. A cron expression is written cron(minutes hours day-of-month month day-of-week year): six required fields, no seconds, and a year at the end. A rate expression is written rate(value unit) with minute(s), hour(s) or day(s). Like Quartz, EventBridge needs ? in one of the two day fields and numbers Sunday as 1.
The tool runs in your browser; nothing you type is sent to a server or to AWS.
How to use
- Paste the expression with or without the
cron(…)wrapper, or arate(…)expression. - Errors name the field and the rule that failed.
- Pick EventBridge rule (always UTC) or EventBridge Scheduler (choose a timezone). A valid cron expression shows a plain-English description and the next 5 runs; runs in a skipped or repeated DST hour are marked. A rate expression shows its interval, since it has no fixed clock times.
- Choose Convert for the Unix cron or Quartz version.
Fields and wildcards
| Field | Allowed values |
|---|---|
Minutes | 0-59, with , - * / |
Hours | 0-23, with , - * / |
Day-of-month | 1-31, with , - * ? / L W |
Month | 1-12 or JAN-DEC, with , - * / |
Day-of-week | 1-7 or SUN-SAT (1 = Sunday), with , - * ? L # |
Year | 1970-2199, with , - * / |
Examples
| Expression | Meaning |
|---|---|
cron(0 10 * * ? *) | At 10:00 UTC every day. |
cron(0 18 ? * MON-FRI *) | At 18:00 UTC, Monday through Friday. |
cron(0 8 1 * ? *) | At 08:00 UTC on the 1st of every month. |
cron(0/15 * * * ? *) | Every 15 minutes. |
cron(0/5 8-17 ? * MON-FRI *) | Every 5 minutes from 08:00 to 17:55 UTC on weekdays. |
cron(15 10 ? * 6L 2026) | At 10:15 UTC on the last Friday of each month in 2026. |
rate(5 minutes) | Every 5 minutes from when the rule is created. |
rate(1 day) | Once a day from when the rule is created. |
Common mistakes
- Copying a crontab line.
0 9 * * 1-5has 5 fields and uses Sunday = 0. The EventBridge version iscron(0 9 ? * 2-6 *)— and it runs at 09:00 UTC, not server time. The Cron Converter does this and flags the timezone. - Copying a Quartz expression. Drop the seconds field and add a year:
0 0 12 ? * MON-FRIbecomescron(0 12 ? * MON-FRI *). - rate(1 hours) or rate(5 minute). The unit must be singular for 1 and plural above 1.
Moving existing schedules to AWS? Read Migrating cron schedules to Databricks (Quartz) and EventBridge.
FAQs
What timezone do EventBridge cron expressions use?
EventBridge scheduled rules evaluate cron expressions in UTC, so cron(0 9 * * ? *) runs at 09:00 UTC. EventBridge Scheduler, the newer service AWS recommends for schedules, evaluates cron and at() expressions in the timezone you set on the schedule. Choose the EventBridge Scheduler profile and a timezone to see local and UTC run times.
Why is my EventBridge cron expression invalid?
The most common causes: only 5 fields (EventBridge needs 6, ending with the year), * in both day fields (one must be ?), a seconds field copied from Quartz, or Sunday written as 0 (EventBridge uses 1-7 with Sunday = 1).
What is the difference between cron() and rate()?
cron() runs at clock times, such as 10:00 UTC every day. rate() runs at a fixed interval counted from when the rule is created, such as rate(5 minutes). Use the singular unit for a value of 1 (rate(1 hour)) and the plural above 1 (rate(2 hours)).
How does EventBridge Scheduler handle daylight saving time?
AWS documents that when clocks go forward, a cron run whose local time does not exist is skipped, and when clocks go back the schedule runs only once. Scheduled rules run in UTC, so they never skip or repeat; their local time moves by an hour instead. The run list marks runs that fall in a skipped or repeated hour.
Can EventBridge run a schedule every 30 seconds?
No. EventBridge cron has no seconds field, and AWS does not support expressions that lead to rates faster than 1 minute.
Can I use more than one # in day-of-week?
No. With # you can define only one expression in the day-of-week field, so 3#1,6#3 is invalid. Create a second rule for the other day.