ISO Date and Time

What is the time in the ISO format?

From different national date formats to a standard one

No confusion when expressing date and time

ISO is the acronym for the International Organization for Standardization ( ISO), a worldwide federation of national standards bodies from 172 countries.

The first standard for expressing a calendar date using numbers and if needed, time, was first published in 1988. It went through several versions and the latest one, currently in use, dates back to 2004.

It is a splendid example of bringing various systems under one rule, and providing an answer that can be read both by humans and computers (or should we now say AI?).

How is an ISO Date and Time formatted?

The basic formula is YYYYMMDD, where YYYY stands for year, MM for month and DD for day, with 0 used when the month, for instance, is just one digit. 20240901 in ISO format is 1 September 2024 in a British-style date and September 1 2024 in an American one. If time is required too, a capital T is inserted between the date and the time: 20240901T153000.

Time is expressed as hhmmss, where h is for hours, m stands for minutes and s is for seconds. Affixing a capital letter Z to the time in ISO format indicates that the time is in UTC/GMT+0, such as 20240901T153000Z.

ISO is a non-governmental organization established in 1947. The mission of ISO is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity.

• Official ISO website: www.iso.org
• The World Wide Web Consortium ( W3C ), the organisation that defines web standards, has a note on ISO date and time format
• For a plain Unix-seconds timestamp instead, see the GMT timestamp page.