Casualties in war are often disputed by opposing sides and counting true numbers is challenging.

Yet after years of disputing the number of casualties reported by the Gaza health authorities since the outbreak of hostilities in October 2023, the Israel Defence Forces (IDF) have now reportedly concurred with estimates that 71,000 Palestinians have been killed. 

Gaza's health ministry figures have long been viewed by international observers as largely reliable reflections on the number of Palestinian casualties. Therefore, the IDF's reported acceptance of Gaza's health figures is not a surprising development, Therese Pettersson, a researcher at the Uppsala Conflict Data Program (UCDP) at Uppsala University in Sweden, told DW.

The UCDP is a four-decade-old program that has, since 2004, made its collection of casualty data publicly available.

"The fact that we have such a thorough record of the fatalities makes it harder to deny that this is going on," said Pettersson.

Conflicting figures from Moscow and Kyiv

It is rare for parties involved in conflicts to agree with one another when it comes to fatalities.

Neither Moscow nor Kyiv provides regular — or, likely, accurate — figures regarding their own losses in the ongoing Russia-Ukraine war.

Russia has provided no official update on its losses in more than three years. 

At the same time, warring factions will often exaggerate the losses of their opponents.

"That's almost universal," said Shawn Davies, another of UCDP's analysts, "In most cases, it's very much that you downplay your own fatalities and 'up play' your success.

"That's a matter of boosting your own supporters' morale in showing success and downplaying whatever the cost is of what you're doing."

Analysts don't just rely on 'official' figures

Monitoring conflict casualties is an exercise in casting a large net to capture as much data as possible.

Those data sources are varied: official notifications from warring parties, hospital and morgue reports, eyewitness accounts, on-the-ground reporting from media and social media posts from the public.

The quality and reliability also differ, so monitors must confirm their information with sources, often entire networks of groups within conflict zones. Monitors then apply their own rules to remove unreliable data and come to accurate figures. UCDP, for example, tends to trust "admitted losses" from a warring party, but not necessarily claims made about their opponents, according to Pettersson.

Among monitoring groups, UCDP's casualty data is at the conservative end of casualty estimates. It focuses only on deaths — not injuries or missing persons, which some monitors count among casualties — and wants its data to be treated as a "baseline" for conflict trend monitoring.

But theirs isn't the only method. 

A recent report from the US-based think tank CSIS found that contrary to certain claims, Russia's progress in its conflict with Ukraine had been minimal and with major losses.

Using data from sources that include the UK Defense Ministry, the Russian news outlet Mediazona and BBC Russian, and interviews with US, European, and Ukrainian government officials, it estimated that: 

• Russia had suffered almost 1.2 million battlefield casualties — killed, wounded and missing — since the start of the war, about a third of these losses were in 2025 alone.
• Between 275,000 and 325,000 Russian battlefield deaths up to December 2025.
• Up to 600,000 Ukrainian casualties, including 100,000-140,000 fatalities.

"These numbers are extraordinary. No major power has suffered anywhere near these numbers of casualties or fatalities in any war since World War II," the CSIS reportsaid of Russia's losses.

The estimates, at least for Russia's fatalities, are consistent with what Davies has found at UCDP.

"I think our best estimate is about 350,000 Russian losses," he told DW.

Every body counts

For years, it's been a common refrain in reporting by conflict scholars and casualty analysts that every body is important.

Lily Hamourtziadou, a war scholar at Birmingham City University in the UK, has spent two decades recording casualties, first for Iraq Body Count and later for other British monitors. 

She said it was a surprise that the IDF had reportedly agreed with Gaza's casualty figures, given how rare it was for states in war to do so. 

"That is definitely a good thing," Hamourtziadou said. "But there could be a number of things [at play], it could be that they know there's a lot higher [casualty figure], so they're agreeing to a lower count."

She said it should not be exceptional that warring parties acknowledge their losses. Instead, accurate recording of the human impact of conflict is a responsibility Hamourtziadou said should lie with states.

"It is, I believe, every state's responsibility, if they are using aggression against any population, to collect data on who they're killing and why," Hamourtziadou said, "That, for me, is a more dignified approach."

Going beyond the numbers is rarely reflected in casualty reporting, but Hamourtziadou said even the simplest pieces of information — names and ages — can help expand not just the impact, but the story of conflict, where media and government reporting can often emphasize military losses over civilians.

Edited by: A.Thomas