How to Enable Week Numbers in Software & Programming

Unlock hidden time settings in your favorite tools. Comprehensive guides on how to enable, calculate, and display ISO 8601 week numbers across different platforms.

Week numbers are a standard way of referencing time in business operations, logistics, and project management across Europe and Asia. However, many US-centric software applications disable this feature by default or hide it deep within configuration menus.

Whether you are trying to configure your personal iPhone calendar, writing a SQL query for a report, or setting up a project timeline in Excel, the specific steps to retrieve the ISO Week Number vary significantly.

The guides below provide the exact steps, formulas, and code snippets required to display the correct week number in the most popular software and programming languages used today.

← Back to Current Week Number

Calendar Apps

Spreadsheets

Programming

Databases

Frequently Asked Questions

Why don't my calendar apps show week numbers by default?

Most calendar applications (like iOS Calendar or Outlook) prioritize daily and monthly views for general consumers. Week numbers are primarily used in business and academic settings, so they are often hidden inside 'Advanced' or 'View' settings to keep the interface clean.

Which week numbering system should I select in settings?

For international business and most modern use cases, you should select 'ISO 8601'. This system ensures that Week 1 is the week containing the first Thursday of the year, and weeks always start on Monday.

Can I get week numbers in Excel without complex formulas?

Yes. While older versions required complex math, modern Excel supports the function =ISOWEEKNUM(date), which automatically calculates the correct standard week number.

Do mobile phones support week numbers?

Yes. Both iPhone (iOS) and Android (Google Calendar) have native settings to toggle week numbers on. They appear as small gray numbers usually on the left side of the calendar view.

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