The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization since 1988 and, before that, it was defined in ISO 2015 since 1971.

How many weeks are in a year?

A calendar year consists of 52 weeks, 365 days in total.

How many weeks are left in the year?

One of our most popular questions, how many weeks left this year! There are 8 weeks and 2 days left until the end of 2021 (until 31st December 2021). Also – find out how many days left this year. Add this to your own 2021 Countdown.