What is the First Day of the Week?

The first day of the week depends on culture, religion, and regional norms. In many Western calendars Sunday comes first. In ISO 8601 and much of Europe, Monday does.

About 55% of the world's population starts the week on Sunday, while about 44% starts on Monday.

Approximate share of population by common calendar convention. Local practice can differ from official business standards.

Why is Sunday the first day of the week?

Sunday-first calendars grew out of older religious and cultural traditions that still shape wall calendars in parts of the Americas and elsewhere.

• Roman tradition.Roman naming of the days placed the Sun's day at the head of the seven-day cycle that later spread through Europe.
• Christian practice.Sunday is observed as the Lord's Day in much of Christianity, which reinforced Sunday as a weekly starting point on many calendars.
• Hebrew calendar context. In the Hebrew week, Sunday follows the Sabbath (Saturday), so Sunday is day one of the new week in that tradition.

What is the first day of the week biblically?

In Jewish and Christian readings of Genesis, creation is told as evening-and-morning days, and the seventh day is set apart as rest. Christian tradition later marked Sunday (the day of the resurrection) as the first day of the week in worship and calendar practice. That religious framing is one reason Sunday-first calendars remain common, even where Monday starts the workweek.

Why is Monday the first day of the week?

The international standard ISO 8601 defines Monday as day 1 of the week. Business software, EU calendars, and week-number systems usually follow it so week 1 and week boundaries stay consistent across countries.

• Standardization. One shared rule for dates, week numbers, and data exchange.
• Workweek alignment. Monday matches how most offices start the working week in Europe and many other regions.

Which countries start the week on Sunday?

Sunday-first calendars are common in the United States, Canada, and many places where consumer calendars still print Sunday in the left column. In some of those same countries, workplaces may still treat Monday as the start of the workweek. The printed calendar and the office week are not always the same thing.

Which countries start the week on Monday?

Most of the European Union, China, Japan, Russia, and countries that adopt ISO 8601 for official or business calendars treat Monday as the first day. Australia and New Zealand generally follow Monday-first rules in modern standards even where older consumer habits vary.

Does the first day change the weekday name?

No. A given date is always the same weekday. What changes is which day begins the seven-day block, and that affects week numbers and “week of” date ranges. If you need week numbers, see our week number calculator.