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Cron Reference

Every 12 Hours

Runs twice per day at midnight and noon.

Cron Expression

0 */12 * * * Test in tool

Every 12 hours

Expression Breakdown

Minute Hour Day Month Weekday
0 */12 * * *
0 every 12 any any any

Next 5 Scheduled Runs

  • Sunday, June 14 2026 at 12:00 AM
  • Sunday, June 14 2026 at 12:00 PM
  • Monday, June 15 2026 at 12:00 AM
  • Monday, June 15 2026 at 12:00 PM
  • Tuesday, June 16 2026 at 12:00 AM

Times are relative to the server's local clock at page load.

Common Use Cases

  • Twice-daily digest emails
  • TLS/SSL certificate status checks
  • Large data export jobs

How to Install

Linux / macOS (crontab)

Run crontab -e and add this line:

0 */12 * * * /path/to/your/script.sh

Python (APScheduler / cron-style)

scheduler.add_job(my_func, 'cron',
    minute='0',
    hour='*/12',
    day='*',
    month='*',
    day_of_week='*')

GitHub Actions (schedule)

on:
  schedule:
    - cron: '0 */12 * * *'

Frequently Asked Questions

What does 0 */12 * * * mean?
Fires at 00:00 and 12:00 every day — exactly twice per day.
How do I run a job at 6 AM and 6 PM?
Use 0 6,18 * * * to specify both hours explicitly.