Cron Expression for Every 3 Hours

0 */3 * * *

At 0 minutes past the hour, every 3 hours. Refreshing third-party feeds that update a few times a day.

Field-by-field breakdown

FieldValueAllowed rangeMeaning
Minute00–59at minute 0
Hour*/30–23every 3 hours
Day of month*1–31every day of the month
Month*1–12every month
Day of week*0–6 (Sunday = 0)every day of the week

Next 5 runs (your time zone)

Calculating upcoming runs…

Cron uses the time zone of the machine or scheduler that runs it, which is often UTC on servers.

How to use this schedule

crontab

0 */3 * * * /path/to/script.sh >> /var/log/job.log 2>&1

Kubernetes CronJob

apiVersion: batch/v1
kind: CronJob
metadata:
  name: my-job
spec:
  schedule: "0 */3 * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: my-job
              image: busybox
              command: ["sh", "-c", "echo running"]
          restartPolicy: OnFailure

GitHub Actions

on:
  schedule:
    - cron: '0 */3 * * *'  # UTC

Frequently Asked Questions

What is the cron expression for every 3 hours?

Use "0 */3 * * *". In plain English: At 0 minutes past the hour, every 3 hours.

What does "0 */3 * * *" mean?

Minute: at minute 0; Hour: every 3 hours; Day of month: every day of the month; Month: every month; Day of week: every day of the week.