What is Interval?
The fixed time gap between consecutive executions of a scheduled job.
Definition
An interval is the recurring time period between one execution and the next. A 15-minute interval means the job runs at :00, :15, :30, and :45 past each hour. Intervals in cron are expressed using the step operator (/) — for example, */15 in the minute field. Unlike fixed-delay scheduling, cron intervals are clock-aligned: a "every 15 minutes" job starts at the top of the hour, not 15 minutes after creation.
Simple Analogy
Like a metronome ticking at a steady beat — the interval is the gap between ticks, and each tick triggers your job to run.
Why It Matters
Choosing the right interval balances responsiveness against resource consumption. A monitoring ping every minute catches outages quickly but generates 1,440 requests per day. Every 5 minutes reduces that to 288 while still detecting issues within 5 minutes. Understanding intervals helps you make this tradeoff consciously.
How to Verify
Check your cron expression's step values. "*/5 * * * *" is a 5-minute interval. Use the Cron Explainer to see consecutive run times and verify the gap matches your intent. In CronJobPro, the job detail page shows the interval between runs.
Common Mistakes
Confusing "every 15 minutes" with "15 minutes after the job finishes." Cron intervals are clock-aligned, not completion-based. Setting an interval shorter than the job's execution time, causing overlapping runs. Using "*/7" and expecting runs exactly 7 minutes apart (it resets each hour: :00, :07, :14, :21, :28, :35, :42, :49, :56, then :00 again — a 4-minute gap).
Best Practices
Choose intervals that divide evenly into 60 for the minute field (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30) to get consistent spacing. If your job takes longer than the interval, enable concurrency protection to prevent overlaps. Monitor actual execution times to ensure your interval is appropriate.
Cron Expression Explainer
Explain a cron expression
Try it free →Frequently Asked Questions
What is Interval?
An interval is the recurring time period between one execution and the next. A 15-minute interval means the job runs at :00, :15, :30, and :45 past each hour. Intervals in cron are expressed using the step operator (/) — for example, */15 in the minute field. Unlike fixed-delay scheduling, cron intervals are clock-aligned: a "every 15 minutes" job starts at the top of the hour, not 15 minutes after creation.
Why does Interval matter for cron jobs?
Choosing the right interval balances responsiveness against resource consumption. A monitoring ping every minute catches outages quickly but generates 1,440 requests per day. Every 5 minutes reduces that to 288 while still detecting issues within 5 minutes. Understanding intervals helps you make this tradeoff consciously.
What are best practices for Interval?
Choose intervals that divide evenly into 60 for the minute field (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30) to get consistent spacing. If your job takes longer than the interval, enable concurrency protection to prevent overlaps. Monitor actual execution times to ensure your interval is appropriate.
Related Terms
Schedule
A defined plan that determines when and how often a job runs.
Recurrence
The repeating pattern that defines how a schedule cycles over time.
Cron Expression
A string of five fields that defines when a scheduled job should run.
Schedule Overlap
When a new job execution starts before the previous one has finished running.
Execution Duration
The measured wall-clock time from when a job starts running to when it finishes.