crontool
Paste a schedule, read it in English, see the next runs.

Cron Expression: Every 20 Minutes

The expression is */20 * * * *. Paste it above to read it in English and preview the next run times. Below: how the step works and the variations people ask for.

The expression

*/20 * * * * runs a job every 20 minutes: at :00, :20 and :40 past every hour.

Field by field

*/20 is a step in the minute field — every 20th minute of 0–59. The trailing * * * * leave hour, day, month and weekday open, so it fires all day.

Same as 0,20,40

*/20 * * * * and 0,20,40 * * * * are identical. The list form is handy when you want irregular offsets like 5,25,45.

How many times it fires

3 times an hour, 72 times a day.

FAQ

How many times a day does */20 * * * * run?

72 times — 3 times per hour across 24 hours.

Is */20 the same as 0,20,40?

Yes, for the minute field they are identical.

How do I offset it to :05, :25, :45?

Use 5,25,45 * * * * — the step form always starts at 0.