Time formats

ISO 8601's repeating intervals format was developed to provide a standardized way to represent recurring time periods, ensuring clear communication across different systems and cultures.

The format is:

R[n]/[start]/[end]

• R[n]: Indicates repetition. "R" stands for "repeat" and "[n]" is the number of repetitions. If "[n]" is omitted, the interval repeats indefinitely.

• [start]: The beginning of the interval in standard date-time format.

• [end]: The end of the interval, either as a date-time or a duration.

Example: R5/2023-08-10T10:00:00Z/2023-08-10T11:00:00Z means an event starts at 10:00 UTC on August 10, 2023, ends at 11:00 UTC the same day, and repeats 5 times.

Most usual use cases

Scenario	Format	Description
Once	yyyy-mm-ddThh:mm:ssZ	yyyy-mm-dd: Represents the date, August 10, 2023. T: Separator between the date and time. hh:mm:ssZ: Specifies the event occurs at 06:00 UTC.
Every day at the same time	R/Thh:mm:ssZ/P1D	R: Indicates the event repeats. T: Separator between the date and time. hh:mm:ssZ: Specifies the event occurs at 06:00 UTC. /: Separator between the start time and the duration. P1D: Indicates the duration between each repetition is 1 day.
At exact days of the week on specific time	R/Mon,Wed,FriThh:mm:ssZ/P1W	R: Indicates the event repeats. Mon,Wed,Fri: Represents the days Monday, Wednesday, and Friday. T: Separator between the date and time. hh:mm:ssZ: Specifies the event occurs at 06:00 UTC. P1W: Indicates the duration between each repetition is 1 week.
Same day at several months at the same time	R/Jan,Apr,Jul-10T06:00:00Z/P3M	R: Indicates the event repeats. Jan,Apr,Jul: Represents the months January, April, and July. -10: Specifies the 10th day of those months. T: Separator between the date and time. hh:mm:ssZ: Specifies the event occurs at 06:00 UTC. P3M: Indicates the duration between each repetition is 3 months.
Several different days in any selected month at the same time	R/Jan-05,10,Apr-05,10,Jul-05,10Thh:mm:ssZ	R: Indicates the event repeats. Jan-05,10,Apr-05,10,Jul-05,10: Represents the 5th and 10th days of January, April, and July. T: Separator between the date and time. hh:mm:ssZ: Specifies the event occurs at 06:00 UTC.

Other configuration

Use case		Description
Change time zone	2023-08-10T06:00:00+02:00	UTC Time: 2023-08-10T06:00:00Z: This represents 6:00 AM on August 10, 2023, in UTC. Time Zone Offset: Positive Offset (ahead of UTC): 2023-08-10T06:00:00+02:00 - This represents 6:00 AM on August 10, 2023, in a time zone that is 2 hours ahead of UTC (e.g., Central European Time during daylight saving). Negative Offset (behind UTC): 2023-08-10T06:00:00-05:00 - This represents 6:00 AM on August 10, 2023, in a time zone that is 5 hours behind UTC (e.g., Eastern Standard Time).
Repeat task	R5/2023-08-10T06:00:00Z/P1D	This means the event starts at 6:00 AM UTC on August 10, 2023, and repeats daily 5 times.