Day of the Week Calculator
Day of the Week Calculator
The Day of the Week Calculator is a quick and easy tool that tells you which day of the week a specific date falls on. Simply select any date, and the calculator will instantly display the exact day—Monday through Sunday—along with useful details such as:
The day’s position in the year (e.g., 219th day of 2025)
How many days remain in the year
Which occurrence of that weekday it is (e.g., 32nd Thursday of the year)
How many of that weekday are left in the year
This calculator is perfect for:
Planning events and special occasions
Finding the day for historical or future dates
Scheduling work, projects, or travel
Learning fun facts about specific dates
It works for any date in history or the future and follows the Gregorian Calendar system. Whether you’re checking your birthday, a historical event, or a project deadline, this tool gives you an instant answer—fast, accurate, and easy to use.
ISO 8601
The International Organization for Standardization (ISO) created ISO 8601, the global standard for exchanging date and time information. This format is widely used in most developed countries, though not universally adopted.
Under ISO 8601:
Monday is considered the first day of the week.
The standard defines a method for determining the day of the week for any given date.
One well-known algorithm used for this is Zeller’s Congruence, developed by Christian Zeller, which calculates the weekday for a specific date.
Gregorian Calendar
The Gregorian Calendar, introduced by Pope Gregory XIII, is the most widely used calendar in the world today.
It is based on the solar year (time taken for Earth to orbit the Sun, about 365 days) and the lunar cycle (about one month).
Early civilizations used the Sun and Moon to track time, and over time, this evolved into the modern calendar system we use today.
Origin of Day Names
The names of the days of the week mostly come from Roman gods—many of which also gave their names to planets and celestial bodies—dating back to the Hellenistic period (323 BC to 31 BC).
Examples:
Sunday – Named after Sol, the Roman Sun god.
Monday – From Luna, goddess of the Moon.
Tuesday – From Mars, god of war.
Wednesday – From Mercurius (Mercury), messenger of the gods.
Thursday – From Jove (Jupiter), king of the gods.
Friday – From Venus, goddess of love.
Saturday – From Saturnus (Saturn), god of wealth and liberation.
Many cultures adapted these names. For example:
In Japanese, Friday (kin-yōbi) means Venus day.
Tuesday (ka-yōbi) translates to Fire Day, linked to Mars.
In many Indian languages, Thursday is Guruvara, meaning Day of the Guru, associated with Jupiter.
Interesting Facts About Each Day
Monday
Statistically the day most likely for U.S. stock market gains.
Only day of the week that forms an anagram: dynamo.
People tend to complain more—about 34 minutes on Mondays versus 22 minutes on other days.
People typically weigh the most on Mondays.
Sometimes called “suicide day” due to higher reported suicide rates.
Tuesday
Often the most productive workday.
The most job applications are submitted on Tuesdays.
Black Tuesday (Oct 29, 1929) marked the U.S. stock market crash that triggered the Great Depression.
Wednesday
Known as Hump Day in the U.S.—the midpoint of the workweek.
Ash Wednesday is a Christian holy day of prayer, fasting, and repentance.
Ash Wednesday also refers to devastating 1983 bushfires in Australia that killed 75 people and caused $300 million in damages.
Thursday
In Christianity, Maundy Thursday (Holy Thursday) marks the Last Supper before Easter.
Thirsty Thursday is a popular term for starting the weekend early with drinks.
Friday
Friday the 13th is considered unlucky in many cultures (though some see it as lucky).
Black Friday in the U.S. is the day after Thanksgiving, signaling the start of the holiday shopping season—often chaotic.
Good Friday is a Christian holy day commemorating the crucifixion of Jesus.
Saturday
The official day of rest in Israel—most businesses and transport shut down.
Official voting day in Australia and New Zealand.
In Sweden, many children are only allowed candy on Saturdays.
Traditionally believed to be the only day to hunt vampires (when they’re in their coffins).
Sunday
In some countries, like parts of the Middle East, Sunday is the first day of the week.
In Christianity, Sunday is the Sabbath—a day of worship and rest.
Most banks worldwide are closed on Sundays.
Any month starting on a Sunday will have a Friday the 13th.
Super Bowl Sunday in the U.S. is one of the largest annual sporting events.
Related Calculator:
Age Calculator, Time CalculatorExternal Resources:
Day of the week Calculator on Calculator.net
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