Cron Expression: */15 * * * *
*/15 * * * *
Run every 15 minutes
Field Breakdown
| Value | Field | Meaning |
|---|---|---|
| */15 | minute | every 15 minutes (0,15,30,45) |
| * | hour | every hour |
| * | day | every day |
| * | month | every month |
| * | weekday | every weekday |
*/15 fires at minutes 0, 15, 30, and 45 of every hour — four times per hour, 96 times per day. It's one of the most common intervals for health checks, polling jobs, and cache warming.
# With flock to prevent overlap: */15 * * * * flock -n /tmp/check.lock /usr/local/bin/health-check.sh
Related Expressions
*/15 * * * *
Every 15 minutes
*/10 * * * *
Every 10 minutes
*/20 * * * *
Every 20 minutes
*/30 * * * *
Every 30 minutes
5,20,35,50 * * * *
Every 15 min starting at :05
Common Use Cases
- Health checks
- Certificate expiry monitoring
- Queue depth checks
- API sync jobs
Paste your crontab to visualise every job on a 24-hour timeline — detect overlaps, collisions, and get flock-safe versions.
Open Cron Visualiser →Frequently Asked Questions
Does */15 always start at minute 0?
Yes. */15 fires at minutes 0, 15, 30, and 45 — these are fixed points relative to the hour, not 15 minutes after the job last ran. To start at a different minute, use a list: 5,20,35,50 * * * *.
How many times does */15 run per day?
4 times per hour × 24 hours = 96 times per day.