Week start by country

How week starts differ around the world

ISO 8601 defines Monday as the first day of the week, and that convention is the safest default for international schedules, week numbers, payroll exports, and analytics. It is especially common across Europe and in many business systems because ISO weeks also define week 1 by the first Thursday of the year, avoiding short partial weeks at New Year.

Country conventions still vary. The United States, Canada, Mexico, Israel, Saudi Arabia, India, Japan, South Korea, Singapore, and several countries in the Americas and Asia use Sunday as the first day in CLDR. Iran, Afghanistan, Bahrain, Qatar, Kuwait, Oman, Jordan, Iraq, Egypt, Algeria, and several other jurisdictions use Saturday. That is why a calendar grid, spreadsheet export, or recurring report can look shifted even when every date is technically correct.

This table follows the Unicode Common Locale Data Repository rather than local anecdotes. CLDR's supplemental weekData is the canonical source used by many internationalization libraries; countries not listed with a specific first-day override inherit the global Monday default. Source: Unicode CLDR supplementalData.xml.