Want to figure out the date that is exactly one hundred days before Jan 1, 2010 without counting?
Your starting date is January 1, 2010 so that means that 1 day later would be December 31, 2009.
You can check this by using the date difference calculator to measure the number of days before Jan 1, 2010 to Dec 31, 2009.
December 31st, 2009 is a Thursday. It is the 365th day of the year, and in the 53rd week of the year (assuming each week starts on a Sunday), or the 4th quarter of the year. There are 31 days in this month. 2009 is not a leap year, so there are 365 days in this year. The short form for this date used in the United States is 12/31/2009, and almost everywhere else in the world it's 31/12/2009.
In some cases, you might want to skip weekends and count only the weekdays. This could be useful if you know you have a deadline based on a certain number of business days. If you are trying to see what day falls on the exact date difference of 1 weekday before Jan 1, 2010, you can count up each day skipping Saturdays and Sundays.
Start your calculation with Jan 1, 2010, which falls on a Friday. Counting forward, the next day would be a Saturday.
To get exactly one hundred weekdays before Jan 1, 2010, you actually need to count 2 total days (including weekend days). That means that 1 weekday before Jan 1, 2010 would be December 30, 2009.
If you're counting business days, don't forget to adjust this date for any holidays.
December 30th, 2009 is a Wednesday. It is the 364th day of the year, and in the 53rd week of the year (assuming each week starts on a Sunday), or the 4th quarter of the year. There are 31 days in this month. 2009 is not a leap year, so there are 365 days in this year. The short form for this date used in the United States is 12/30/2009, and almost everywhere else in the world it's 30/12/2009.
Type in the number of days and the exact date to calculate before. If you want to find a previous date, you can enter a negative number to figure out the number of days before the specified date.
This site provides an online Days Before Date Calculator to help you find the date that occurs exactly X days before a specific date. You can also enter a negative number to find out when X days before that date happened to fall. You can use this tool to figure out a deadline if you have a certain number of days remaining. Or read the full page to learn more about the due date if you're counting business days or weekdays only, skipping Saturday and Sunday. If you're trying to measure the number of days between two dates, you can switch to the Date Difference Calculator instead.
An attack on a nightclub in Istanbul, Turkey, during New Year's celebrations, kills at least 39 people and injures more than 60 others.
Portuguese politician and diplomat António Guterres was officially elected Secretary-General of the United Nations.
The Address Downtown Dubai burns over midnight as the New Year is rung in. The blaze started on the night of New Year's Eve 2015, by currently unknown causes. There was one fatality.
At least 60 people are killed and 200 injured in a stampede after celebrations at Félix Houphouët-Boigny Stadium in Abidjan, Ivory Coast.
2013 Houphouët-Boigny stampede, Stade Félix Houphouët-Boigny, Abidjan, Ivory Coast
A bomb explodes as Coptic Christians in Alexandria, Egypt, leave a new year service, killing 23 people.
A suicide car bomber detonates at a volleyball tournament in Lakki Marwat, Pakistan, killing 105 and injuring 100 more.
Sixty-six people die in a nightclub fire in Bangkok, Thailand.
Adam Air Flight 574 disappears over Sulawesi Strait, Indonesia with 102 people on board.
In a vote of confidence, General Pervez Musharraf wins 658 out of 1,170 votes in the Electoral College of Pakistan, and according to Article 41(8) of the Constitution of Pakistan, is "deemed to be elected" to the office of President until October 2007.
Motion of no confidence, Pervez Musharraf, Electoral College (Pakistan), Constitution of Pakistan, President of Pakistan
Euro currency becomes legal tender in twelve of the European Union's member states.
Euro currency is introduced in 11 member nations of the European Union (with the exceptions of the United Kingdom, Denmark, Greece and Sweden; Greece later adopts the euro).
Russia begins to circulate new rubles to stem inflation and promote confidence.
Curaçao gains limited self-government, though it remains within free association with the Netherlands.
The World Trade Organization goes into effect.
The Draupner wave in the North Sea in Norway is detected, confirming the existence of freak waves.
The Zapatista Army of National Liberation initiates twelve days of armed conflict in the Mexican state of Chiapas.
The North American Free Trade Agreement (NAFTA) comes into effect.
Dissolution of Czechoslovakia: Czechoslovakia is divided into the Czech Republic and Slovakia.
Dissolution of Czechoslovakia, Czechoslovakia, Czech Republic, Slovakia
David Dinkins is sworn in as New York City's first black mayor.
The Montreal Protocol comes into force, stopping the use of chemicals contributing to ozone depletion.
The Evangelical Lutheran Church in America comes into existence, creating the largest Lutheran denomination in the United States.
Evangelical Lutheran Church in America, Lutheranism, Religious denomination
The first British mobile phone call is made by Michael Harrison to his father Sir Ernest Harrison, chairman of Vodafone.
The original American Telephone & Telegraph Company is divested of its 22 Bell System companies as a result of the settlement of the 1974 United States Department of Justice antitrust suit against AT&T.
AT&T Corporation, United States Department of Justice, Competition law, Breakup of the Bell System
Brunei becomes independent of the United Kingdom.
The ARPANET officially changes to using the Internet Protocol, creating the Internet.
Peruvian Javier Pérez de Cuéllar becomes the first Latin American to hold the title of Secretary-General of the United Nations.
Peru, Javier Pérez de Cuéllar, Latin America, Secretary-General of the United Nations
Greece is admitted into the European Community.
Formal diplomatic relations are established between China and the United States.
Air India Flight 855 Boeing 747 crashes into the sea, due to instrument failure and pilot disorientation, off the coast of Bombay, India, killing 213.
Denmark, the United Kingdom, and Ireland are admitted into the European Economic Community.
Denmark, United Kingdom, Republic of Ireland, European Economic Community
Cigarette advertisements are banned on American television.
The People's Democratic Party of Afghanistan is founded in Kabul, Afghanistan.
The Federation of Rhodesia and Nyasaland is divided into the independent republics of Zambia and Malawi, and the British-controlled Rhodesia.
Federation of Rhodesia and Nyasaland, Zambia, Malawi, Rhodesia
Western Samoa achieves independence from New Zealand; its name is changed to the Independent State of Western Samoa.
Cameroon achieves independence from France and the United Kingdom.
Fulgencio Batista, dictator of Cuba, is overthrown by Fidel Castro's forces during the Cuban Revolution.
European Economic Community established on this day.
George Town, Penang becomes a city by a royal charter granted by Elizabeth II.
Standard practice uses this day as the origin of the age scale Before Present
United Nations cease-fire takes effect in Kashmir from one minute before midnight. War between India and Pakistan stops accordingly.
The British railway network is nationalized to form British Railways.
The American and British occupation zones in Germany, after World War II, merge to form the Bizone, which later (with the French zone) became part of West Germany.
The Canadian Citizenship Act 1946 comes into effect, converting British subjects into Canadian citizens. Prime Minister William Lyon Mackenzie King becomes the first Canadian citizen.
Canadian Citizenship Act 1946, British subject, William Lyon Mackenzie King
World War II: In retaliation for the Malmedy massacre, U.S. troops kill 60 German POWs at Chenogne.
World War II: The German Luftwaffe launches Operation Bodenplatte, a massive, but failed attempt to knock out Allied air power in northern Europe in a single blow.
The Declaration by United Nations is signed by twenty-six nations.
Safety glass in vehicle windscreens becomes mandatory in the United Kingdom.
Alcatraz Island becomes a United States federal prison.
Nazi Germany passes the "Law for the Prevention of Genetically Diseased Offspring".
The United States Post Office Department issues a set of 12 stamps commemorating the 200th anniversary of George Washington's birth.
The former municipalities of Point Grey, British Columbia and South Vancouver, British Columbia are amalgamated into Vancouver.
Boris Bazhanov defects through Iran. He is the only assistant of Joseph Stalin's secretariat to have defected from the Eastern Bloc.
Boris Bazhanov, Iran, Joseph Stalin, Eastern Bloc emigration and defection
The Cristero War begins in Mexico.
Britain's Railways are grouped into the Big Four: LNER, GWR, SR, and LMS.
List of railway companies involved in the 1923 grouping, London and North Eastern Railway, Great Western Railway, Southern Railway (UK), London, Midland and Scottish Railway
The Belorussian Communist Organisation is founded as a separate party.
The SPT Airboat Line becomes the world's first scheduled airline to use a winged aircraft.
The Republic of China is established.
Captain David Beatty is promoted to Rear admiral, and becomes the youngest admiral in the Royal Navy (except for Royal family members), since Horatio Nelson.
David Beatty, 1st Earl Beatty, Rear admiral, British Royal Family, Horatio Nelson, 1st Viscount Nelson
For the first time, a ball is dropped in New York City's Times Square to signify the start of the New Year at midnight.
The first American college football bowl game, the Rose Bowl between Michigan and Stanford, is held in Pasadena, California.
College football, Bowl game, Rose Bowl Game, Pasadena, California
Nigeria becomes a British protectorate.
The British colonies of New South Wales, Queensland, Victoria, South Australia, Tasmania, and Western Australia federate as the Commonwealth of Australia; Edmund Barton is appointed the first Prime Minister.
New South Wales, Queensland, Victoria (Australia), South Australia, Tasmania, Western Australia, Federation of Australia, Australia, Edmund Barton, Prime Minister of Australia
Spanish rule ends in Cuba.
New York, New York annexes land from surrounding counties, creating the City of Greater New York. The four initial boroughs, Manhattan, Brooklyn, Queens, and The Bronx, are joined on January 25 by Staten Island to create the modern city of five boroughs.
City of Greater New York, Manhattan, Brooklyn, Queens, The Bronx, Staten Island
Ellis Island opens to begin processing immigrants into the United States.
Twenty-five nations adopt Sandford Fleming's proposal for standard time (and also, time zones)
Ferdinand de Lesseps begins French construction of the Panama Canal.
Queen Victoria of the United Kingdom is proclaimed Empress of India.
American Civil War: The Emancipation Proclamation takes effect in Confederate territory.
American Civil War, Emancipation Proclamation, Confederate States of America
Porfirio Díaz conquers Mexico City, Mexico.
First Polish stamp is issued.
The world's first "Mercy" Hospital is founded in Pittsburgh by the Sisters of Mercy; the name will go on to grace over 30 major hospitals throughout the world.
The United Kingdom claims sovereignty over the Falkland Islands.
The Greek Constitution of 1822 is adopted by the First National Assembly at Epidaurus.
Greek Constitution of 1822, First National Assembly at Epidaurus
The Bishop of Durham, Shute Barrington, orders troops from Durham Castle to break up a miners' strike in Chester-le-Street, Co. Durham
Major-General Lachlan Macquarie officially becomes Governor of New South Wales
The United States bans the importation of slaves.
The French Republican Calendar is abolished.
French rule ends in Haiti. Haiti becomes the first black republic and second independent country in North America after the United States
Emperor Gia Long orders all bronze wares of the Tây Sơn dynasty to be collected and melted into nine cannons for the Royal Citadel in Huế, Vietnam.
The legislative union of Kingdom of Great Britain and Kingdom of Ireland is completed to form the United Kingdom of Great Britain and Ireland.
Kingdom of Great Britain, Kingdom of Ireland, United Kingdom of Great Britain and Ireland
Ceres, the largest and first known object in the Asteroid belt, is discovered by Giuseppe Piazzi.
First edition of The Times of London, previously The Daily Universal Register, is published.
American Revolutionary War: One thousand five hundred soldiers of the 6th Pennsylvania Regiment under General Anthony Wayne's command rebel against the Continental Army's winter camp in Morristown, New Jersey in the Pennsylvania Line Mutiny of 1781.
6th Pennsylvania Regiment, Anthony Wayne, Morristown, New Jersey, Pennsylvania Line Mutiny
American Revolutionary War: Norfolk, Virginia is burned by combined Royal Navy and Continental Army action.
American Revolutionary War, Norfolk, Virginia, Burning of Norfolk, Royal Navy, Continental Army
The hymn that became known as "Amazing Grace", then titled "1 Chronicles 17:16-17" is first used to accompany a sermon led by John Newton in the town of Olney, Buckinghamshire, England.
The first traveler's cheques, which can be used in 90 European cities, go on sale in London, England.
Bouvet Island is discovered by French explorer Jean-Baptiste Charles Bouvet de Lozier.
John V is crowned King of Portugal.
Russia begins using the Anno Domini era instead of the Anno Mundi era of the Byzantine Empire.
Charles II is crowned King of Scotland.
Scotland begins its numbered year on January 1 instead of March 25.
Croatian nobles elect Ferdinand I of Austria as King of Croatia in the Parliament on Cetin.
Ferdinand I, Holy Roman Emperor, List of rulers of Croatia, Parliament on Cetin
King Francis I of France succeeds to the French throne.
The present-day location of Rio de Janeiro, Brazil is first explored by the Portuguese.
Albert II of Habsburg is crowned King of Hungary.
Michael VIII Palaiologos is proclaimed co-emperor of the Empire of Nicaea with his ward John IV Laskaris.
Michael VIII Palaiologos, Empire of Nicaea, John IV Laskaris
Romanos IV Diogenes marries Eudokia Makrembolitissa and is crowned Byzantine Emperor.
Romanos IV Diogenes, Eudokia Makrembolitissa, Byzantine Emperor
Grand Prince Stephen I of Hungary is named the first King of Hungary by Pope Sylvester II.
Emperor Honorius forces Galla Placidia into marriage to Constantius, his famous general (magister militum).
Telemachus, a Christian monk, is killed for attempting to stop a gladiators' fight in the public arena held in Rome.
The Senate chooses Pertinax against his will to succeed Commodus as Roman emperor.
The Roman legions in Germania Superior refuse to swear loyalty to Galba. They rebel and proclaim Vitellius as emperor.
The Roman Senate posthumously deifies Julius Caesar.
The Julian calendar takes effect as the civil calendar of the Roman Empire, establishing January 1 as the new date of the new year.
Roman consuls begin their year in office.