Learn cron syntax through interactive lessons, challenging quizzes, and real-time visual timelines.
Cron expressions have 5 fields separated by spaces. Each field controls when a job runs.
| Field | Allowed Values | Special Characters | Example |
|---|---|---|---|
| Minute | 0–59 | * , - / | */15 = every 15 min |
| Hour | 0–23 | * , - / | 9-17 = 9 AM to 5 PM |
| Day of Month | 1–31 | * , - / | 1,15 = 1st and 15th |
| Month | 1–12 | * , - / | */3 = every 3 months |
| Day of Week | 0–6 (Sun–Sat) | * , - / | 1-5 = Mon–Fri |
* — Every ValueThe asterisk means "every possible value" for that field.
* * * * * → Every minute of every hour, every day.
30 * * * * → Minute 30 of every hour (1:30, 2:30, 3:30…)
0 * * * * → Top of every hour (1:00, 2:00, 3:00…)
, — List of ValuesSeparate individual values with commas.
0 9,12,18 * * * → At 9:00, 12:00, and 18:00 every day.
0 0 1,15 * * → Midnight on the 1st and 15th of every month.
0 0 * * 0,6 → Midnight every Saturday and Sunday.
- — Range of ValuesDefine a continuous range between two values.
0 9-17 * * * → Every hour from 9 AM to 5 PM.
0 0 * * 1-5 → Midnight Monday through Friday.
30 1-3 * * * → 1:30, 2:30, and 3:30 AM every day.
/ — Step ValuesSkip values in steps. */N means "every Nth value."
*/15 * * * * → Every 15 minutes (0, 15, 30, 45).
0 */2 * * * → Every 2 hours (0:00, 2:00, 4:00…).
0 0 */3 * * → Every 3 days at midnight.
Mix special characters for precise schedules.
30 9 * * 1-5 → 9:30 AM Monday–Friday.
0 */6 * * 1-5 → Every 6 hours on weekdays (0:00, 6:00, 12:00, 18:00).
15,45 8-18 * * 1-5 → :15 and :45 past each hour, 8 AM–6 PM, weekdays.
0 0 1 1,7 * → Midnight on Jan 1st and Jul 1st.
Test your knowledge with 20 questions across three difficulty levels.
Choose difficulty:
Type any cron expression and see its next 5 fire times on a visual timeline.
See when your cron expression fires next.
20-question quizzes across three difficulty levels. Multiple choice and free-form answer types to solidify your cron knowledge.
See the next 5 fire times for any cron expression rendered on an interactive timeline. Instantly verify your expressions are correct.
Your quiz scores are saved in your browser so you can track improvement over time. See your best scores per difficulty level.
Step-by-step lessons covering wildcards, commas, ranges, steps, and complex combined expressions. Learn at your own pace.
Online cron expression editor and validator.
Official crontab documentation and reference.
*), the cron fires when either condition matches. For example, 0 0 1 * 5 fires at midnight on the 1st of the month and every Friday. To fire only on the 1st when it's a Friday, some cron implementations use the ? character.Enter your email to receive weekly cron tips and quiz challenges.
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