How many people died in WW1? Start and end dates of First World War, why did it happen, and who won?

Around 40 million people are thought to have been directly affected by the war worldwide

As the nation takes pause to remember those who gave their live to fight for our country in conflicts across history on Remembrance Day, it’s time to reflect on those lost to war.

World War I is ranked among the deadliest conflicts in human history.

Sign up to our NationalWorld Today newsletter

The i newsletter cut through the noise

Beginning on 28 July 1914 and rolling on for over four years until 11 November 1918, the war - sparked by the assassination of Archduke Franz Ferdinand of Austria - was eventually won by the Allied powers, which included Great Britain.

Here is everything you need to know.

Why did World War I happen?

When the Archduke Franz Ferdinand of Austria was assassinated on 28 June 1914, the Austro-Hungarian Empire blamed Serbia and declared war on the country.

Russia then declared war on the Austro-Hungarian Empire, which set off a chain of events in which members both groups of countries declared war on each other.

The two sides involved in the conflict were the Allied Powers (mainly Russia, France and the British Empire), and the Central Powers (mainly Germany, Austria-Hungary and the Ottoman Empire).

How many people died in World War I?

In total, it is estimated that 15 to 22 million lives were lost to the First World War around the globe.

Of those, nine to 11 million military personnel are thought to have perished in the conflict, while the civilian death toll was about six to 13 million.

In terms of which ‘side’ suffered the most losses, the Allies are thought to have lost about six million military personnel, while the Central Powers lost about four million.

About two-thirds of military deaths in World War I were in battle. Disease, including the 1918 flu pandemic and deaths while held as prisoners of war caused about one third of total military deaths.

At least two million people died from diseases and six million went missing, presumed dead.

How many total casualties were there?

In terms of total casualties - that is, people killed or injured as a result of the conflict - around 40 million people are thought to have been directly affected by the war worldwide.

It’s hard to give a definitive number of casualties or deaths that occurred as a result of World War I, as statistics vary to a great extent.

The methods used by nations to record and classify casualties was not uniform, and newer research after the fact has revised many totals - including those of Great Britain - to include military personnel outside of combat theatres, such as those who provided logistical and service support.

Which country was worst affected?

Death totals recorded during and after the war cannot be considered comparable in all cases, due to the fact different nations have or had different methods to record their casualties.

However, the country that is thought to have suffered the most war dead is Russia, with an estimated 2.8 to 3.4 million total casualties.

However, that is only roughly 1.75% of the total population of the nation at the time.

The country that suffered the greatest loss in terms of population percentage was Qajar Persia (now modern day Iran), which lost around 20% of its residents - two million people.

As far as Britain fared, the UK recorded between 867,829 and 1,011,687 deaths - roughly 2% of the population.

A message from the editor:

Thank you for reading. NationalWorld is a new national news brand, produced by a team of journalists, editors, video producers and designers who live and work across the UK. Find out more about who’s who in the team, and our editorial values. We want to start a community among our readers, so please follow us on Facebook, Twitter and Instagram, and keep the conversation going. You can also sign up to our newsletters and get a curated selection of our best reads to your inbox every day.