The first day of the week varies depending on cultural, religious, and international standards:
- According to the international standard ISO 8601, Monday is considered the first day of the week. This standard is widely used in Europe and many other parts of the world for business and official purposes
- In many countries, especially in the United States, Canada, and the United Kingdom, Sunday is traditionally regarded as the first day of the week. This is rooted in religious traditions, where Sunday is considered the Lord's Day in Christianity, following the Sabbath (Saturday) as the seventh day
- The choice between Sunday and Monday as the first day often reflects cultural and religious practices. For example, Sunday is the first day in many Abrahamic traditions, while Monday marks the start of the workweek in industrialized societies
In summary, Monday is the first day of the week according to the international ISO standard, while Sunday is considered the first day in many religious and cultural contexts, especially in North America and parts of the Christian world
