Difference Between World War I and World War II

Edited by Diffzy | Updated on: May 11, 2023


Difference Between World War I and World War II

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World War I and II are the most devastating wars in history, as the major nations warred with each other. Millions of lives were lost in these wars, and people shudder to think of the atrocities that occurred during them. The catastrophic aftermaths of these wars made the nations take measures to ensure that such a war never takes place again.

Ernst Haeckel, a German biologist, first used the term World War. Before the start of World War II, World War I was simply referred to as the Great War. After WWII took place British historians referred to the Great War as the First World War and American historians favored the term World War I. Who would have thought an assassination would lead to a war between the nations? But that is precisely what happened. The assassination of Archduke Franz Ferdinand of Austria by Gavrilo Princip for the movement known as Young Bosnia; this event led to a number of other events that eventually resulted in WWI.

The Treaty of Versailles signed at the end of WWI caused unrest among Germans. Adolf Hitler (though despicable, an excellent example of how a skilled speaker can sway the masses) swore to undo the injustice of the Treaty and initiated the German invasion of Poland. This invasion led to the deadliest war of all time – WWII.

World War I Vs. World War II

World War I started in 1914, whereas World War II started in 1939. In WWI Japan was one of the allies; however, in WWII Japan was one of the Axis.

Difference Between World War I And World War II In Tabular Form

Parameters Of ComparisonWorld War IWorld War II
DurationWWI lasted for a period of 4 years. It started on 28th July 1914 and ended on 11th November 1918.WWII lasted for a period of 6 years (from 1939 to 1945).
CauseThe assassination of the Archduke Franz Ferdinand of Austria by a Bosnian Serb.The rise of Nazism and fascism, political and economic instability in Germany, and several other factors are considered to be the cause of WWII. The precise trigger that led to the war is still debated.
War betweenWWI took place between the Allies and the Central Powers. The former consisted of France, UK, Russia, Italy, Japan, and the US, whereas the latter consisted of Germany, Austria-Hungary, and the Ottoman Empire.The WWII was between the Allies and the Axis. France, Britain, the US, the Soviet Union, Canada, and China made up the Allies. The Axis consisted of Germany, Italy, and Japan.
Which was the deadliest war?WWI is considered one of the deadliest wars in history; however, it is not the deadliest war in history.WWII is the deadliest war in history.
CasualtiesMore soldiers were killed compared to civilians. 9 million soldiers were killed, and 23 million were wounded. Moreover, 5 million civilians died in this war.More civilians were killed compared to soldiers. 70 – 80 million fatalities (mostly among civilians) were estimated. Genocides, massacres, starvation, and disease were the cause of civilian casualties.
Methods of warfareWWI was fought using trench warfare, machine guns, early airplanes, and poisonous gas.WWII was fought using nuclear power (atomic bombs), submarines, and tanks. Secret communications became more complex during this war.
SuccessorWWII succeeded WWI.The Cold War succeeded WWII.

What Is World War I?

The assassination of Archduke Franz led to the July Crisis – a month of a diplomatic clash between Austria-Hungary and Germany with Russia, France, and Britain. This crisis resulted in WWI. Austria declared war on Serbia, and Russia mobilized its army to aid Serbia. Germany allied with Austria and declared war on Russia and France, as they had mobilized their armies to help Serbia. Britain chose to remain out of this clash until Germany invaded Belgium; when Germany refused to heed Britain’s ultimatum and retreat from Belgium, the latter declared war on the former.

Due to miscommunication between Germany and Austria, the latter was forced to split its armies and fight Russia and Serbia, while Germany dealt with France. In 1915, Serbia became the first to use anti-aircraft warfare, as it shot down an Austrian plane. Though Austria was suffering, Germany was initially successful in the war. However, one of its commanders disobeyed orders, which led to a gap between the German armies. The French and the British Army exploited this gap and drove back the German forces. Later, the Russian army, too, joined the fray. Germany unable to bear attacks from two fronts resigned itself to defeat.

The Ottoman Empire was a threat to Russia and Britain; however, Russia emerged successful. Germany attempted to negotiate peace with the Allies on 12th December 1916, but the effort was rejected as a ruse. In April 1917, the United States joined the war and allied with Britain and France. The US intervention was due to Germany’s unrestricted submarine warfare that resulted in the death of many American citizens.

In 1918, Germany again gained the upper hand for a while; the German army used several infiltration techniques to penetrate British and French infantry. For a while, it looked like Germany would win the war. However, the Allied offense also known as the hundred days offense began on 8th August 1918. The German forces felt the death knell at the Battle of Albert on 21st August and made a peace offer to Belgium, which was refused. After that, it was a losing battle for Germany and Austria.

On 3rd November, Austria sent a truce flag to the Allies requesting an armistice. Following that, the Armistice of Villa Giusti was signed. An Armistice was signed with Germany on November 11th. On the eleventh hour of the eleventh day of the eleventh month, the armies ceased fire. As no allied force had entered Berlin, the stab-in-the-back myth came into existence. According to the myth, the German army was not defeated by the Allied forces but by the Jews who sabotaged the war effort. The war formally ended when the Treaty of Versailles was signed.

What Is World War II?

World War II started on 1st September 1939 when Germany invaded Poland; the United Kingdom and France declared war on Germany in retaliation on 3rd September 1939. Adolf Hitler became the chancellor of Germany in 1933, and later in 1934, proclaimed himself Fuhrer. He soon began the rearmament campaign in violation of the Treaty of Versailles, which eventually led to World War II.

On 17th September 1939, the Soviet Union invaded Poland and annexed its eastern part, whereas Germany annexed its western part. Estonia, Latvia, and Lithuania were forced to sign pacts that allowed the Soviet Union to form military bases in their lands. When Finland refused to sign a similar pact, the Finno-Soviet war began. The war ended in 1940 when Finland conceded some of its territories.

Germany invaded Denmark and Norway in April 1940. The invasion of Norway caused Neville Chamberlain to resign and Winston Churchill to become the Prime Minister of Britain on 10th May. On 10th June, France was invaded by Italy; the German military seized the opportunity and attacked the weakened French army. It captured Paris on 14th June (a great blow to France indeed!). Later, France was divided into German and Italian occupation zones.

Germany’s next target was Britain. The air Battle of Britain began in July; however, Germany failed to establish its superiority. The Tripartite Pact was signed in September 1940, which united Japan, Italy, and Germany as the Axis Powers. If any country other than the Soviet Union attacked one of the Axis Powers, it will have to deal with all three countries. Hungary, Slovakia, and Romania joined the Axis powers in November. In December 1940, Roosevelt accused Hitler of trying to conquer the world. Following this accusation, the United States began preparing to wage war against the German army.

On 31st July 1940, Hitler decided to eliminate the Soviet Union, as he believed it could ally with Britain and wage war against Germany. Supported by Italy and Romania, Germany attacked the Soviet Union on 22nd June 1941. In July the United States and the Soviet Union allied together to defeat Germany. As the war progressed, the German army nearly reached Moscow but was forced to rest. The Soviet Union still held the key cities and its army drove back the Germans 100-250 km.

In early 1940, Japan and China clashed. America aided China and engaged in secret conversations with the United Kingdom and the Netherlands to defend against Japan if it dared to attack. Attempts at peaceful negotiations notwithstanding, Japan attacked American and British holdings – the most famous of the attacks was the Pearl Harbor attack. The US, UK, China, and Australia declared war on Japan as a result. Initially, Japan enjoyed immense success; however, the Americans broke its naval code in May 1942 and defeated the Imperial Japanese Navy when they tried to capture Port Moresby.

In February 1943, the German troops were defeated at Stalingrad by the Soviet Union. From then on, things began to go south for Germany. The Soviets ensured that Germany couldn’t emerge victorious. In September, the Allies invaded Italy, but they reached the main German defense line only in November. The Allied forces neutralized the major Japanese base in the Caroline Islands at the end of March 1944. From 27th January 1944 on, the Soviet Union enjoyed phenomenal success in war and drove back the Axis Powers.

The Allied forces entered France on 6th June 1944 (D-Day) and defeated the German units there; Codenamed Operation Neptune this invasion was the largest seaborne invasion in history. On 30th April 1945, the German Nazi army was finally defeated. However, the Japanese Government did not concede to surrender unconditionally. Therefore, in August, the United States dropped atomic bombs on Hiroshima and Nagasaki (Japanese cities). On August 15, 1945, Japan surrendered and the surrender documents were signed on 2nd September. Thus, the grueling war ended.

Main Difference Between World War I And World War II In Points

  • The Treaty of Versailles was signed to end World War I in 1919, whereas the Treaty of Peace was signed in Japan to end World War II and facilitate the removal of allied armies from Japan.
  • Germany surrendered to the Allies on November 11, 1918, in World War I. In World War II, Japan surrendered to the Allies on September 2, 1945.
  • World War II was deadlier than World War I due to the advancement in weapons technology, which resulted in the invention of nuclear bombs.
  • Woodrow Wilson was the President of America during World War I, whereas Franklin D. Roosevelt and Harry Truman were the presidents of America during World War II.
  • H. H. Asquith and Lloyd George were the Prime Ministers of Britain during World War I. The infamous Winston Churchill was the Prime Minister during World War II (remember that inspiring speech at the end of the film Darkest Hour? Gary Oldman gave a stellar performance as Winston Churchill!).
  • World War I was referred to as ‘The war to end all wars’. On the other hand, World War II was known as The Great Patriotic War.
  • The Versailles Treaty caused a lot of resentment in Germany. Hitler used this opportunity to engage in war with the Allies. Therefore, World War I indirectly led to World War II.


Though both wars were condemned and labeled devastating, deadly, and disastrous, some viewed them as a logical result of the events that took place at that time. Some historians opined that World War I was not a fight about nothing but a war of ideals – a clash between aggressive militarism and liberal democracy. The discontent caused by Germany’s defeat in WWI and the stab-in-the-back myth eventually led to WWII.

The aftermath of this war was so devastating that people never wished to see another war again. However, something good happened because of these unalterable wars. Wristwatches became indispensable everyday wear and radios became popular, as a result of this war (guess every cloud has a silver lining).


  • https://en.wikipedia.org/wiki/World_War_I
  • https://en.wikipedia.org/wiki/World_War_II


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"Difference Between World War I and World War II." Diffzy.com, 2024. Sat. 15 Jun. 2024. <https://www.diffzy.com/article/difference-between-world-war-i-and-world-war-ii>.

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