A numbers game What we know about the balance of power between the Russian and Ukrainian armies — and how mobilization could change it

In May, a new law tightening mobilization procedures will come into force in Ukraine. While the law doesn’t specify how many people the Ukrainian authorities may call up for service, the number 500,000 was mentioned repeatedly during discussions over the draft legislation. Meanwhile, rumors suggest that Ukraine’s mobilization efforts could prompt a similar response from Russia. Meduza analyzed the current strength of both countries’ armies to better understand how mobilization could change the power balance and whether the armies are equipped to accommodate such a significant influx of new troops.

Who has more troops?

It’s difficult to determine the precise number of troops in Russia and Ukraine’s armies. While officials on both sides have made statements on the matter, these can’t be taken at face value.

Back in the summer of 2022, Ukrainian Defense Minister Oleksii Reznikov said that there were around one million people in the country’s defense forces. However, judging by the number of formations and units involved in combat since then, either the actual number was much lower or most of these people were never sent to the front.

According to the annual International Institute for Strategic Studies (IISS) Military Balance report, in 2023, the total number of troops in Ukrainian defense forces (comprising Ukraine’s Ground Forces, Territorial Defense Forces, Marine Corps, Air Force, National Guard, and police) was somewhere between 641,000 and 941,000. However, the IISS didn’t specify exactly where these people were serving or whether or not they were involved in combat. For instance, experts estimate that there are about 100,000 people in Ukraine’s police force, yet there’s only one police brigade at the front.

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In late 2023, Russian President Vladimir Putin said there were 617,000 Russian servicemen in the “special military operation zone.” Of these, we know that over 250,000 were drafted in 2022. According to Putin, another 486,000 people enlisted in the army. Russia’s military (including its “volunteer corps”) has sufficient formations and units to accommodate 617,000 military personnel. However, there’s no evidence that these units are fully staffed, and some of them may not even exist. Moreover, it’s highly doubtful that the Russian military command’s plans to further increase troop numbers are realistic; there may not be enough weapons, equipment, or officers to pull this off.

According to the IISS report, Russia’s military has about 600,000 regular troops. However, more than 100,000 are conscripts who can’t be sent to the front. There are about another 600,000 in volunteer units and Russia’s National Guard. While almost all of the volunteer units are fighting in Ukraine, only a few National Guard brigades are at the front.

It’s impossible to tell the true balance of military strength from such diverse reports. But there’s another set of data that can give a more accurate picture of the situation on the front: the number of formations and units that are definitively deployed there. Knowing the number of formations and units, we can roughly group them into approximate “battalions.” A more detailed picture isn’t possible since there’s no information on how staffed various units are. Ukrainian soldiers have been raising concerns over personnel shortages in their combat units. While there are fewer such complaints in the Russian army right now, they were widespread as recently as fall 2022.

Russia’s army

At the beginning of 2024, the Russian army had 22 large tactical formations, encompassing motorized infantry, tank, airborne, and marine divisions. However, it’s unclear if certain newly formed divisions are fully established and operational. For example, there were plans to create a marine division based on the 155th Guards Naval Infantry Brigade, but this may or may not have happened.

Divisions are, on average, about the size of three brigades. When the Donbas “people’s militias” were integrated into the Russian army, this added another 48 brigades. This means there are an estimated 114 brigades in Russia’s Ground Forces. Additionally, there are another 16 “volunteer brigades,” although they likely have fewer battalions than regular ones. There are also reconnaissance brigades and special forces brigades within the Russian Armed Forces; however, these have fewer troops than motorized infantry brigades. Finally, it’s worth noting the Chechen brigade in Russia’s National Guard, as well as other units created in Chechnya.

In early 2022, 21 regiments were formed after mobilization in Ukraine’s Russian-annexed Donetsk and Luhansk regions. (A regiment can’t conduct independent combat operations and therefore is not a tactical formation, but in terms of infantry, it may have the same strength as a brigade.) Furthermore, between 90 and 100 reserve regiments were created in Russia following mobilization. Some of them were later incorporated into regular formations or disbanded to deploy personnel to reinforce other units or formations.

Taking all this into account, we can roughly estimate the size of Russia’s army to be around 130 brigades (excluding individual artillery, missile, and engineering units), alongside several dozen regiments (each with about the same personnel numbers as a motorized infantry brigade).

Ukraine’s army

At the beginning of 2024, Ukraine’s defense forces comprised approximately 75 regular brigades, encompassing ground forces, marines, and airborne troops, as well as those from the National Guard and police (as with the Russian Armed Forces, artillery and missile brigades aren’t accounted for). There were an additional 31 brigades in the Territorial Defense Forces. However, a small number of regular brigades may only exist on paper; some have been sent to regroup after heavy fighting, while others have been assigned to guard quiet parts of the border with Russia and Belarus. There are also several dozen separate battalions and units (including those with foreign volunteers).

Ukraine is also in the process of forming several more motorized and motorized infantry brigades. Some Territorial Defense Forces brigades are being reclassified as motorized (or have already had their status changed). This brings the total estimated number of brigades to around 105 to 110 — though they have varying levels of combat effectiveness.

It’s difficult to draw direct comparisons between Ukrainian and Russian brigades due to differences in battalion numbers. Leaked Pentagon documents revealed that in 2023, Ukrainian brigades typically had five infantry battalions, while Russian brigades had three. However, in 2024, there were signs that the number of battalions in Russian brigades and regiments has now been increased to five. It’s not entirely clear whether this was done universally or if there were exceptions.

Taking all this into account, the estimated number of infantry battalions in the Russian army ranges from 540 (with three-battalion brigades and regiments and 50 separate reserve regiments) to 1,000 (with a five-battalion structure and 70 separate reserve regiments). Meanwhile, there are an estimated 550 to 570 such battalions in the Ukrainian Armed Forces.

Comparing the number of personnel is even more difficult. In February 2023, the Pentagon estimated the size of a Ukrainian battalion at 250 to 500 personnel and a Russian one at 300 (out of an authorized strength of 500). It’s likely that Russian battalions have since received major reinforcements from reserve regiments and newly recruited contract soldiers. Meanwhile, in 2023, the Ukrainian command spent significant reserves on forming new units, creating around 15 new brigades for the summer offensive.

In any case, these rough estimates show that the Russian Armed Forces’ presumed advantage in combat units may not be so significant — if it even exists at all.

Supply and demand

To understand how many more soldiers Russia and Ukraine need, it’s important to get an accurate picture of the losses both sides have suffered. Official estimates can’t be deemed reliable as both sides conceal their casualties. (Both Kyiv and Moscow claim to have put nearly half a million enemy troops out of action while only losing tens of thousands themselves.)

By analyzing inheritance data, Meduza and Mediazona have calculated that around 120 Russian servicemen are killed every day. This number only pertains to military personnel with Russian citizenship, including convicts sent to war from prison; it doesn’t account for foreigners, including Ukrainian citizens fighting in units that were formerly part of the “people's militias.” Factoring in the severely wounded, those deemed unfit for further service, and those missing in action, Russia’s irrecoverable losses could reach up to 65,000 in a six-month period (not including foreigners).

While the exact number of casualties in the Ukrainian Armed Forces is unknown, indirect evidence shows it may be about the same as on the Russian side. Databases compiled from open-source information contain approximately the same number of names. These numbers can’t be taken at face value, though: the data collection methods may differ, as well as the proportion of published obituaries to the number of deceased. However, a conservative estimate suggests that Ukraine needs to call up around 50,000 people for service every six months to compensate for its losses.

Judging by reports from the front, the Ukrainian army also needs to fill an existing shortage of personnel in combat units. Assuming that the strength of infantry battalions in the Ukrainian Armed Forces has dropped on average to 250 individuals (with an authorized strength of 500), then with the current number of battalions it would take around 140,000 to 145,000 new recruits to fill them. (There’s no information on the average personnel shortage in the Russian army.)

With these numbers in mind, Ukraine would need no more than 200,000 people to cover losses and shortages over the next six months. If Ukraine does mobilize 500,000 people, it can be assumed that the remaining 300,000 would go to staffing new units. The army could fill 60 new brigades with that many recruits. However, it’s unclear what these brigades would be armed with or where they would get ammunition.

In late 2022, early 2023, Ukraine (with help from the West) formed about 15 new brigades for its summer offensive. During this time, the U.S. sent approximately $12.5 billion worth of weapons and ammunition to Ukraine. The new U.S. aid package allocates the same amount of military assistance, and aid from other Western countries isn’t expected to increase significantly compared to 2023, so it’s hard to imagine that Ukraine will be able to form more than another 15 new brigades in the coming months. For example, 60 mechanized infantry brigades (each with one tank battalion) would require more than 1,500 tanks. In 2023, Ukraine’s Western allies promised to supply it with just over 800 tanks. (In reality, only slightly more than 500 were delivered.)

However, if the Russian command decides to conduct a similar mobilization, it will face the same problems. Even current plans to create new formations (through upped enlistment, not a new wave of mobilization, according to the Russian Defense Ministry’s claims) appear unrealistic. It’s unclear where the equipment to arm them would come from. Russian Defense Minister Sergey Shoigu announced plans to form 14 new divisions and 16 new brigades in 2024 (an estimated total of 58 brigades in terms of personnel and equipment). Filling them will require about 250,000 to 300,000 new recruits. But, more importantly, these brigades and divisions will need 1,500 to 2,000 tanks.

In theory, Russia has these tanks. It’s been pulling decommissioned Soviet ones from storage and sending them for modernization. However, considering the current pace of losses, stock in storage may be depleted by 2025. There also aren’t enough new tanks being produced to outfit a large number of new formations. Russia is facing the exact same problem with other equipment like armored personnel carriers, infantry fighting vehicles, and artillery.

These equipment shortages could hinder both countries’ efforts to bolster their military capabilities and achieve decisive breakthroughs on the front lines. While the Ukrainian army can address personnel shortages in existing units by accelerating mobilization, it’s unlikely that it will be able to quickly correct the imbalance in sheer numbers of formations. In turn, the Russian command may announce a new limited mobilization in response to the Ukrainian one in order to maintain its current advantage. However, it’s also incapable of drastically increasing the size of its armed forces without sufficient resources to outfit them.