The United States and Israel attacked Iran on February 28, and initial estimates suggest a heavy running cost for this war.

Last week, the Israeli Finance Ministry claimed that the country is spending $3 billion per week as it attacked Iran, and defended itself from Iranian missiles. In the US, the costs are reportedly even higher. According to a briefing by the Department of Defence (or War, as the Trump Administration calls it) to the US Congress on March 11, the US government had spent $11.3 billion in just the first six days of the war — that’s close to $2 billion a day and $14 billion a week.

For perspective, $1 billion is roughly equal to Rs 9,000 crore. In other words, in the first six days starting February 28, the US and Israel had spent over Rs 1.3 lakh crore. Another way to look at this is to compare it with India’s entire defence budget for 2026: Rs 7.8 lakh crore. So, at the going rate, in just six weeks, which is one of the many timelines US President Donald Trump has given since the start of the war, US and Israel would have spent on this war as much as India hopes to spend in the coming year on its defence.

Of course, it is entirely possible that as the days and weeks go by, the direct running cost may come down — after all, Trump has said that almost all the targets that could be hit aerially have been hit. On the other hand, it is unclear how long this war will drag on, especially since there is no clarity on the exact goal.

While accurately assessing the true cost of war is near impossible, one way to get a sense of the scale is to look at the cost of past wars.

The Watson School of International and Public Affairs in Brown University runs a Cost of War research project. According to a 2021 study here, “the total budgetary costs and future obligations of the post-9/11 wars (including the estimated future costs for veteran’s care) is …about $8 trillion in current dollars.”

The pie-chart alongside provides the detailed break up of these expenses.

But even these costs are only those that will fall on the US government and US taxpayers. If, as seems more and more likely, this war settles down to a lower frequency of attacks and counterattacks, the focus of costs will shift from direct military costs to the US and Israel to indirect costs to the wider world, such as the cost of higher fuel prices.

Crude oil prices have shot up by almost 50% since the start of the war. That increase will now feed inflation across the world, worsening the so-called cost of living crisis that started in the wake of the Russia-Ukraine war in 2022.

But even such inflationary bumps fail to truly capture the real cost of war. For instance, what is the opportunity cost of any such war? Opportunity cost refers to the “money which could have gone towards societally beneficial expenditures such as infrastructure improvements, educational investments, and environmental protection” instead of military spending.

Beyond the economic costs, are the human costs — again far more difficult to assess. For instance, the Cost of War project finds that an estimated over 940,000 people were killed by direct post-9/11 war violence in Iraq, Afghanistan, Syria, Yemen, and Pakistan between 2001-2023. Of these, more than 432,000 were civilians.

The post 9/11 wars have also led to a severe undermining of civil liberties and human rights. “Domestically, the post-9/11 wars dramatically expanded mass surveillance, eroding constitutional protections, and intensified police militarization. Marginalized and racialized groups, from Muslims and Arabs to Black and Indigenous organizers to migrants, have borne the brunt of these consequences,” the project notes.

Lastly, there are environmental costs because “military jets and vehicles consume petroleum-based fuels at an extremely high rate, and the vehicles used in the war zones produce tons of carbon monoxide, nitrogen oxides, hydrocarbons, and sulfur dioxide in addition to CO2”. One of the key findings has been that the US Department of Defense is the world’s single largest institutional consumer of oil — and as a result, one of the world’s top greenhouse gas emitters.