Developer4 min read
Cron Expression Parser - How to Read and Write Cron Schedules
Cron expressions control scheduled tasks on Linux servers, cloud platforms (AWS EventBridge, GCP Cloud Scheduler), and CI/CD pipelines. But cron syntax is cryptic - even experienced developers struggle to read 0 6 * * 1-5 at a glance. A cron parser translates the expression into plain English and shows upcoming execution times.
Cron Expression Format
A standard 5-field cron expression:
| Field | Allowed Values | Special Characters |
|---|---|---|
| Minute | 0-59 | * , - / |
| Hour | 0-23 | * , - / |
| Day of month | 1-31 | * , - / ? L W |
| Month | 1-12 or JAN-DEC | * , - / |
| Day of week | 0-6 or SUN-SAT | * , - / ? L # |
Common Cron Expressions
* * * * *- every minute0 * * * *- every hour (at minute 0)0 6 * * *- every day at 6:00 AM0 6 * * 1-5- weekdays at 6:00 AM*/15 * * * *- every 15 minutes0 0 1 * *- first day of every month at midnight0 0 * * 0- every Sunday at midnight30 4 * * 1- every Monday at 4:30 AM
Special Characters
*- any value (every minute, every hour, etc.),- list:1,15means the 1st and 15th-- range:1-5means 1 through 5/- step:*/10means every 10th;0-30/5means 0,5,10,15,20,25,30?- no specific value (day fields only, when you specify one day field and want "any" in the other)L- last (last day of month, or last Saturday)W- nearest weekday to the given day#- nth day:6#3means the 3rd Friday
Free Online Cron Parser
Use SnapSum Cron Parser to translate cron expressions into human-readable descriptions and see upcoming execution times.
- Enter any cron expression and get a plain-English description
- Shows the next 5-10 execution dates and times
- Supports 5-field (standard) and 6-field (with seconds) formats
- Validates your expression and highlights errors
Step-by-Step: Parse a Cron Expression
- Open Cron Parser.
- Enter your cron expression (e.g.,
0 9 * * 1-5). - Read the plain-English description: "At 09:00, Monday through Friday."
- Check the next execution times to verify correctness.
6-Field Cron (with Seconds)
Some platforms (AWS EventBridge, Spring, Quartz) use a 6-field cron with a seconds prefix. Example: 0 0 6 * * ? means "every day at 6:00:00 AM." The parser detects and handles both formats.