Cost: $4.7 Trillion* (2021)
Location: Worldwide
Duration: 1939-1945

The Second World War began because of one man’s need for power and his desire to erase, through genocide, an entire race of people and anyone who stood in his way. For the second time in 25 years, the world united against Germany. This time, in a war that was costlier in every possible way than any previous war, and, almost, every subsequent one as well.

World War 2 ©Everett Collection / Shutterstock.com

Adjusted to today, the War that redefined the layout of World War 2 might not be the costliest war in history, but it comes pretty close, and, with an estimated 85 million casualties, it is by far the deadliest. The collateral cost of Germany’s attempt at world domination was more than $33 billion in reparations to civilians, survivors of the holocaust, and the State of Israel.

Cost: $2.8 Trillion* (2021)
Location: United States
Duration: 1812-1815

With Great Britain preoccupied with the Napoleonic Wars in Europe, the United States looked to take advantage of the situation by expanding its territory north into British North America. In other words, America wanted to invade what is now Canada. The war ended in 1815, but not before British forces marched on Washington and set the White House ablaze.

War of 1812 ©Everett Collection / Shutterstock.com

In today’s money, almost $3 trillion was spent on the War of 1812, and there was very little (if anything) to show for the 3 years of fighting, except for an exceptionally sized debt, from which it took the United States about 20 years to recover.

Cost: $10 Trillion*
Location: Worldwide
Duration: 1947-1991

The Cold War is humankind’s costliest war to date and, ironically, not a single shot was fired between the two nations that headlined each side of the “battlefield”. The war began in the aftermath of the Second World War as a race, between Russia and the United States – a race to power – and ended when the Soviet Union dissolved in 1991.

The Cold War ©Only_NewPhoto / Shutterstock.com

The $10 trillion that went into the Cold War, mainly, includes the cost of the nuclear arms race that went on between the two superpowers – on which America spent $5.8 trillion.

Cost: $1.12 Billion*
Location: Israel
Duration: June 5, 1967 – June 10, 1967

For 6 days in June of 1967, the State of Israel was under attack from all sides by all five of its surrounding neighbors, as well as Iraq (for good measure). Although Israeli forces were outnumbered 2.5 to 1, they still managed to push back their aggressors and win the war.

The 6 Day War ©Government Press Office (Israel) / commons.wikimedia.org

For less than 1 week of fighting, it cost more than $1 billion, but that was a small price to pay for Israel, which ended up with the priceless commodities of the Golan Heights, West Bank, Gaza Strip, East Jerusalem, and the Sinai Peninsula for its trouble – the latter of which was given back to Egypt upon agreeing to a peace treaty with Israel.

Cost: $91 Billion* (2021)
Location: United States
Duration: 1861-1865

The American Revolution is considered by many to be the most important War to have taken place on American soil, others, however, give that honor to the American Civil War that took place between the Union and Confederate states and, consequently, brought on the end to slavery in America.

The American Civil War ©Everett Collection / Shutterstock.com

The confederates spent just shy of $23 billion (2021), compared to the $68 billion (2021) that the Union spent. In order to pay for the war, the U.S. government printed paper money for the first time (greenbacks) and also sold about half of a billion dollars in bonds.

Cost: $1-$10 Billion*
Location: Nigeria
Duration: 1967-1970

In 1967, a few years after Nigeria was decolonized by the British, the Republic of Biafra announced its independence from the rest of the country, and, needless to say, the Nigerian government was not too thrilled, and a civil war broke out that lasted for the better part of 3 years.

Nigerian Civil War ©David Cairns/Getty Images

The cost of Biafra’s 3-year failed attempt at independence is estimated to have been somewhere in the $1-$10 billion range, with much of the cost being incurred due to the military supplies that the Nigerian government had received as support from Britain, the United States, and the Soviet Union.

Cost: $250 Billion*
Location: Bosnia
Duration: 1992-1995

In the aftermath of Yugoslavia’s breakup in the early-‘90s, the peoples of Bosnia were at an impasse. The country was split in two, with Croatia supporting Bosnia, and Serbia backing those who opposed the new nation-state. The ensuing war was a brutal one. One where genocide and destruction overwhelmed the country.

Bosnian War ©Public Domain / commons.wikimedia.org

In total, close to a quarter of a trillion dollars went into the Bosnian War. If we count only the damages caused to the Bosnian capital, Sarajevo – which came to around $18.5 billion – we’d have a larger cost than many of the other wars that have taken place throughout history.

Cost: $35 Billion* (2021 Adjusted)
Location: Russia
Duration: 1917-1922

In February of 1917, a revolution in Russia saw the end of the Russian Monarchy – which had been the ruling force in the world’s largest country for over 1000 years – and a new republic, the Russian Republic, was installed as a temporary governing force.

The Russian Civil War ©Public Domain / commons.wikimedia.org

By October of 1917, the new republic had been overthrown, and Russia was tossed into a bloody civil war that lasted for the better part of the next 5 years, ending with the Red Army taking over, and the formation of the Soviet Union. The tab of 50 billion rubles ($650 million*) for the civil war might not seem like a lot, but, today, that would equate to about $35 billion.

Cost: $341 Billion (2011)
Location: Korea
Duration: 1950-1953

The escalation and ensuing war that occurred in Korea is not very well known amongst people from outside of Korea and America. It began when North Korea invaded South Korea, in 1950, and ended, in 1953, with an armistice (a formal peace treaty is still yet to be signed between the two Koreas), and the borders of both countries were nearly identical to when the war began.

Korean War ©Public Domain / commons.wikimedia.org

When the Korean War ended, the price tag on the 3-years of fighting totaled close to $30 billion ($341 billion, 2011), but the real cost is the more than 3 million people who lost their lives including, approximately, 1.2 million civilian casualties of war.

Cost: $88.7 Billion*
Location: Sudan
Duration: 1983-2005

People don’t know very much about the Civil Wars that have disrupted life in Sudan for all but about a dozen years since 1955. The effects of what happened during the Second Sudanese Civil War – the most costly and deadly of the conflicts – are still being felt today.

Sudanese Civil War @msfinternational/Facebook

When the Sudan People’s Liberation Army (SPLA) stood up against the central Sudanese government’s push to expand its territory, impose sharia law, and rid the country of all who didn’t share their beliefs, a 22-year civil war broke out that cost an estimated $88.7 billion and ended with the SPLA helping South Sudan gain its independence.

Cost: $8 Trillion*
Location: Worldwide
Duration: 2001-Present

In response to the events of September 11th, 2001, U.S. President George. W. Bush declared war, not on any country specifically but against terrorism in general – which, inevitably, led to the invasions of Afghanistan and Iraq. The War on Terror has gone on for more than 2 decades, and, although the operation in Afghanistan has come to an end (for now), the War is far from over.

War On Terror @robynbychak / Pinterest.com

By the time America withdrew from Afghanistan, nearly, $2 trillion had gone into the effort in that country alone. In total, the War on Terror has, thus far, cost somewhere in the vicinity of $8 trillion – putting it near the top of the list of the costliest wars in history.

Cost: $35 Billion* (2021 Adjusted)
Location: South Africa
Duration: 1899-1902

At the turn of the 20th century, Great Britain was engaged in a bloody war with the South African Republic and the Orange Free State over its influence in the region. British forces gained a quick upper hand when they pushed the Boar forces back.

The Boer War ©Public Domain / commons.wikimedia.org

Over the subsequent 3 years of the war, British troops impeded the Boar force’s chances of victory by burning farms, destroying livestock, and exporting Boar POWs to far-off British colonies. At the time, the cost of the war was around $285 million, that’s more than $35 billion in today’s money.

Cost: $3.89 Billion*
Location: Spain
Duration: 1936-1939

When a government is unable to accept the decisions of the democratic process, the result is, usually, a civil war. And that’s exactly what happened in the late-1930s, when an insurrection by Spanish Nationalists, who were backed by Italy, Portugal, and Nazi Germany, defeated the Spanish government (backed by the Soviet Union, Mexico, and France).

The Spanish Civil War ©Everett Collection / Shutterstock.com

By the end of the war, the Nationalists, who spent, approximately, $2.04 billion, outspent the Republicans ($1.85 billion) and ended up winning the war. The result was a Francisco Franco-led dictatorship in Spain for the next 36 years.

Cost: $40.65 Billion*
Location: Kosovo
Duration: 1998-1999

A few years after the conclusion of the Bosnian War, the southern part of what was formerly known as Yugoslavia found itself in a war of its own. The war between the Kosovo Liberation Army (KLA) and the Federal Republic of Yugoslavia lasted for about a year and a half and was brought to an end when NATO airstrikes forced Yugoslavian forces to abandon Kosovo.

Kosovo War ©Northfoto / Shutterstock.com

At a cost of more than $40 billion, the Kosovo War, although short and localized, was one of the most expensive in history. The economic fallout of the fighting is still felt by many cities in the central Balkans.

Cost: $3.3 Trillion (2021)
Location: Worldwide
Duration: 1914-1918

On July 28th, 1914, one month after the assassination of Archduke Franz Ferdinand, a war broke out like none other that the world had ever seen. The artillery was more powerful, aerial and submarine attacks were added to the global warfare repertoire, and there were more than 20 million casualties of war.

World War 1 ©Everett Collection / Shutterstock.com

More than $3 trillion* (in today’s money) was spent on the Great War with most of that coming from Germany, Britain, France, the United States, and Russia (in that order). To give you an idea of how bad of a hit Germany’s economy took due to the war, it got to the point where it cost about $10 for a loaf of bread (which would have been, approximately, 428 billion German marks at the time).