Week Number Calculator
Find the current week number or the week number for any specific date according to ISO 8601 standard.
Select Date
Week Number
ISO Week Number
W5
There are 52 or 53 weeks in a year according to ISO standard.
ISO Week Number
ISO 8601 is the international standard for week numbers. Week 1 is the week with the first Thursday of the Gregorian year.
Frequently Asked Questions
How many weeks in a year?
Most years have 52 weeks, but some have 53 weeks depending on the calendar alignment.