Cron expression: every 3 hours

Open in the Cron Expression Generator →

What 0 */3 * * * means

Cron reads five fields from left to right: minute, hour, day of the month, month and day of the week. For every 3 hours they are:

Next runs

Calculated in your browser for your time zone. On a server, cron uses the server’s time zone (often UTC).

1. Enable JavaScript to see the next run times.

Typical uses

• Syncing inventory
• Running crawlers

Good to know

Runs at 00:00, 03:00, 06:00 … 21:00 — 8 times a day.

Use it in crontab, GitHub Actions, Kubernetes and Node.js

crontab (crontab -e):

0 */3 * * * /usr/local/bin/my-job.sh >> /var/log/my-job.log 2>&1

GitHub Actions (times are UTC):

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

Kubernetes CronJob:

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

Node.js (node-cron):

import cron from 'node-cron';
cron.schedule('0 */3 * * *', () => {
  // your job
});

Related schedules

• Every hour — 0 * * * *
• Every 2 hours — 0 */2 * * *
• Every 4 hours — 0 */4 * * *
• Every 6 hours — 0 */6 * * *
• Every 12 hours — 0 */12 * * *