Cron expression `*/30 16 16 DEC 0,6` runs every 30 minutes, between 16:00 and 16:59, on day 16 of the month, and on Sunday and Saturday, only in December

Read more in the dedicated guide: Cron every 30 minutes.

What this cron means, field by field

Each field of */30 16 16 DEC 0,6 controls one dimension of the schedule. Hover over any value in the editor above to see its tooltip; the table below summarises the same information.

Field	Value	Means	Range / hint
minute	`*/30`	every 30 minutes	0-59. The minute(s) of the hour the job will fire.
hour	`16`	at hour 16	0-23. The hour(s) of the day the job will fire (0 = midnight, 23 = 11 PM).
day of month	`16`	at day of month 16	1-31. The day(s) of the month. Use * if you want every day.
month	`DEC`	at month DEC	1-12 or JAN-DEC. The month(s). Use * for every month.
day of week	`0,6`	at day of week 0, 6	0-7 or SUN-SAT (0 and 7 both mean Sunday). Use * for every day of the week.

Next 5 runs

Shown in UTC. Change the timezone in the editor.

Next runs · UTC

Sat 5 Dec · 16:00in 80d 0h
Sat 5 Dec · 16:30
Sun 6 Dec · 16:00
Sun 6 Dec · 16:30
Sat 12 Dec · 16:00

Similar cron expressions

Common variations and tweaks of */30 16 16 DEC 0,6.

*/15 16 16 DEC 0,6Every 15 minutes, between 16:00 and 16:59, on day 16 of the month, and on Sunday and Saturday, only in December

Where else this cron could be used

The same expression */30 16 16 DEC 0,6 works in:

Standard Unix crontab (5-field syntax).
AWS EventBridge / Lambda Scheduled (with a 6th field for year, often *).
Vercel cron jobs (declared in vercel.json).
Quartz Scheduler and node-cron, robfig/cron and similar libraries.

Examples

0 18 * * *
Every day at 18:00
0 */5 * * *
Every 5 hours
0 18 * * 1-5
Weekdays at 18:00
0 0 1 * *
Once a month, on the 1st at midnight

Cheatsheet

Full cheatsheet

Field	Req.	Range	Wildcards
minute	yes	0-59	, - * /
hour	yes	0-23	, - * /
day of month	yes	1-31	, - * /
month	yes	1-12 or JAN-DEC	, - * /
day of week	yes	0-6 or names; some dialects use 0-7 or 1-7 — see Dialects	, - * /

Frequently asked questions

What does the cron expression `*/30 16 16 DEC 0,6` mean?

every 30 minutes, between 16:00 and 16:59, on day 16 of the month, and on Sunday and Saturday, only in December.

When does `*/30 16 16 DEC 0,6` run next?

The next runs (UTC): 2026-12-05 16:00; 2026-12-05 16:30; 2026-12-06 16:00; 2026-12-06 16:30; 2026-12-12 16:00.

Is `*/30 16 16 DEC 0,6` a valid cron expression?

Yes - CronTool's parser accepts this expression and the calendar projects future runs successfully.