Does 0 */2 * * * run at exactly midnight?

Yes — step values in the hour field start from 0, so */2 always includes hour 0 (midnight) as its first match, then every 2 hours after.

How do I run every 2 hours starting from 1 AM instead?

Use a range with a step: 0 1-23/2 * * * produces 1 AM, 3 AM, 5 AM, and so on — odd hours instead of even ones.

Is every 2 hours a good interval for health checks?

It's on the slower end for health checks — most uptime monitoring wants 1–5 minute intervals to catch outages quickly. Every 2 hours suits periodic maintenance more than availability monitoring.

Cron: Every 2 Hours

0 */2 * * * fires twelve times a day, on the even hour — 00:00, 02:00, 04:00, and so on through 22:00. Since 2 evenly divides 24, this step value produces a genuinely consistent, rolling interval, unlike odd step values such as 45 minutes.

0 */2 * * *

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Examples & Variations

0 */2 * * *

Every 2 hours, all day

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0 8-20/2 * * *

Every 2 hours, 8 AM–8 PM only

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0 1-23/2 * * *

Every 2 hours, odd hours instead (1, 3, 5...)

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Common Mistakes

Assuming */2 in the hour field starts counting from deploy time — like all step values, it's anchored to hour 0 (midnight), not to whenever the cron entry was created.
Using 2-hour polling for something that needs faster feedback — this interval suits periodic sync and light maintenance, not anything user-facing that needs near-real-time updates.
Forgetting that 0 */2 * * * still fires overnight — add an hour range (like 8-20/2) if the job should only run during waking hours.

Best Practices

This is a solid default for moderate-cost jobs that don't need hourly freshness — cache refreshes, periodic exports, or non-urgent sync tasks.
Combine with an hour range to restrict to business hours if the job supports a feature nobody uses overnight.
If two different jobs both run every 2 hours, offset one to odd hours (1-23/2) so they don't compete for the same resources simultaneously.

Frequently Asked Questions

Does 0 */2 * * * run at exactly midnight?: Yes — step values in the hour field start from 0, so */2 always includes hour 0 (midnight) as its first match, then every 2 hours after.
How do I run every 2 hours starting from 1 AM instead?: Use a range with a step: 0 1-23/2 * * * produces 1 AM, 3 AM, 5 AM, and so on — odd hours instead of even ones.
Is every 2 hours a good interval for health checks?: It's on the slower end for health checks — most uptime monitoring wants 1–5 minute intervals to catch outages quickly. Every 2 hours suits periodic maintenance more than availability monitoring.

Related Tools

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Cron: Every 45 Minutes

*/45 * * * * does NOT run every 45 minutes on a rolling basis — it only matches minutes 0 and 45. See why, and how to actually get even 45-minute spacing.

Cron: Every 3 Hours

The cron expression for every 3 hours is 0 */3 * * *, firing 8 times a day. See examples, mistakes, and best practices for this schedule.

Cron: Every 4 Hours

The cron expression for every 4 hours is 0 */4 * * *, firing 6 times a day. See examples, mistakes, and best practices for this schedule.