ISO Standards

ISO-8601 calendar system

The ISO-8601 calendar system, also known as the International Standard Organization (ISO) 8601 Data and time - Representation and exchange, is an international standard for the representation of dates and times. It defines a well-defined, unambiguous way to exchange date and time information across different countries and cultures, avoiding confusion and misinterpretation.

Key characteristics of the ISO-8601 calendar system:

• Basic format: The basic format for representing a date is YYYY-MM-DD, where:

  • YYYY represents the four-digit year (e.g., 2024 for the current year)

  • MM represents the two-digit month (01 for January, 02 for February, etc.)

  • DD represents the two-digit day of the month (01 for the first day, 31 for the last day, etc.)

• Time representation: Time is typically represented in 24-hour format using hours-minutes-seconds notation, separated by colons (e.g., 15:08:23).

• Optional components: The standard allows for optional components like:

  • Milliseconds: Can be added after seconds with a decimal point (e.g., 15:08:23.123).

  • Timezone offset: Can be specified using the Z character for UTC or the plus/minus symbol followed by the offset in hours and minutes (e.g., 2024-03-05T15:08:23+05:30 for a time 5 hours and 30 minutes ahead of UTC).

• Week dates: The standard also defines a format for representing dates based on the week number and day of the week (e.g., 2024-W10-5 for the fifth day of the tenth week in 2024).

• Ordinal dates: Dates can be represented based on the day of the year (e.g., 2024-064 for the 64th day of 2024).

Benefits of using ISO-8601:

• Universality: It's an internationally recognized standard, avoiding confusion and ensuring accurate data exchange across borders.

• Machine-readable: The structured format makes it easy for computers to parse and interpret dates and times.

• Sorting: Dates in ISO-8601 format can be easily sorted chronologically due to their numerical representation.

Examples:

• Date only: 2024-03-05 (today's date)

• Date and time: 2024-03-05T15:08:23 (today's date and time at 3:08 PM)

• Date and time with timezone: 2024-03-05T15:08:23Z (today's date and time in UTC)

• Date and time with offset: 2024-03-05T15:08:23+05:30 (today's date and time 5 hours and 30 minutes ahead of UTC)