The 7 Days of the Week
The seven days of the week are Sunday, Monday, Tuesday, Wednesday, Thursday, Friday and Saturday — the order used on US calendars. The international standard ISO 8601 starts the week on Monday (day 1) and ends it on Sunday (day 7). Today is Thursday, November 5, 2026.
Updated · By the YearlyCalendar.org team
The days of the week in order
ISO 8601, the international date standard, numbers the days from Monday = 1 to Sunday = 7. US calendars show Sunday in the first column.
| Day | ISO 8601 number | Position on US calendars | Abbr. | Short |
|---|---|---|---|---|
| Sunday | 7 | 1 | Sun | Su |
| Monday | 1 | 2 | Mon | Mo |
| Tuesday | 2 | 3 | Tue | Tu |
| Wednesday | 3 | 4 | Wed | We |
| Thursday | 4 | 5 | Thu | Th |
| Friday | 5 | 6 | Fri | Fr |
| Saturday | 6 | 7 | Sat | Sa |
Where the names of the days come from
| Day | Old English | Named after | Latin | French | Spanish |
|---|---|---|---|---|---|
| Sunday | Sunnandæg | the Sun | dies Solis | dimanche | domingo |
| Monday | Mōnandæg | the Moon | dies Lunae | lundi | lunes |
| Tuesday | Tīwesdæg | Tiw (Norse Týr), a Germanic god of war, matched with Mars | dies Martis | mardi | martes |
| Wednesday | Wōdnesdæg | Woden (Norse Odin), chief of the Germanic gods, matched with Mercury | dies Mercurii | mercredi | miércoles |
| Thursday | Þunresdæg | Thunor (Norse Thor), god of thunder, matched with Jupiter | dies Iovis | jeudi | jueves |
| Friday | Frīgedæg | Frige (Norse Frigg), wife of Woden, matched with Venus | dies Veneris | vendredi | viernes |
| Saturday | Sæternesdæg | Saturn, the Roman god | dies Saturni | samedi | sábado |
The seven-day week named after the seven classical planets — the Sun, the Moon, Mars, Mercury, Jupiter, Venus and Saturn — spread through the Roman Empire. Germanic peoples replaced most of the Roman gods with their own: Tiw for Mars, Woden for Mercury, Thunor for Jupiter and Frige for Venus. That is why English uses Norse and Germanic names, while French and Spanish keep the Roman ones (mardi, martes for Mars). Saturday is the only English weekday named after a Roman god. In French and Spanish, Sunday comes from Latin dies Dominicus, “the Lord's day”, and Saturday from “Sabbath”.
Which day does the week start on?
Calendars in different countries start the week on different days. The defaults below come from the Unicode CLDR locale data that phones, computers and web browsers use to lay out calendars:
- Sunday: United States, Canada, Mexico, Brazil, Japan, South Korea, India, Israel, the Philippines, South Africa and Saudi Arabia.
- Monday: the United Kingdom, Ireland, Germany, France, Spain, Italy, the Netherlands, Russia, Turkey, China, Australia, New Zealand and the United Arab Emirates.
- Saturday: Egypt, Iran, Iraq, Jordan, Kuwait, Qatar, Oman, Bahrain, Syria, Libya, Algeria, Afghanistan and Sudan.
- Friday: the Maldives.
ISO 8601 weeks always run Monday to Sunday, and ISO week numbers follow that rule — see the current week number.
How many of each weekday in 2026 and 2027
| Weekday | 2026 | 2027 |
|---|---|---|
| Sundays | 52 | 52 |
| Mondays | 52 | 52 |
| Tuesdays | 52 | 52 |
| Wednesdays | 52 | 52 |
| Thursdays | 53 | 52 |
| Fridays | 52 | 53 |
| Saturdays | 52 | 52 |
A year has 52 full weeks plus 1 day (2 in a leap year), so one or two weekdays occur 53 times. 2026 has 53 Thursdays because it starts on a Thursday and ends on one; 2027 has 53 Fridays.
Frequently asked questions
Why are there seven days in a week?
The seven-day week comes from the ancient Near East. The Jewish week ends with the Sabbath on the seventh day, and Hellenistic astrology linked each day to one of the seven classical planets. The planetary week spread through the Roman Empire, and in AD 321 Emperor Constantine made Sunday an official day of rest.
How is a weekday written in an ISO week date?
As year, week and day number: January 1, 2027 is written 2026-W53-5, meaning day 5 (Friday) of ISO week 53 of 2026.
Which days are weekdays?
In the United States, weekdays are Monday to Friday and the weekend is Saturday and Sunday. 2026 has 261 weekdays and 104 weekend days.