Worlds of Design: How Big is Your Army?

For those who prefer "realistic" numbers in RPGs: Inflated numbers of combatants for battles litter history books, derived from wildly inaccurate contemporary histories. We can do much better in figuring out actual numbers.

For those who prefer "realistic" numbers in RPGs: Inflated numbers of combatants for battles litter history books, derived from wildly inaccurate contemporary histories. We can do much better in figuring out actual numbers.


Picture courtesy of Pixabay.

Some GMs don't care about practical limitations, and will happily claim an army is hundreds of thousands strong. But that kind of nonsense will put off some players, breaking their immersion in the setting, destroying their suspension of disbelief - because it's nonsense, barring extraordinary magic or combatants who don't need to eat!

As player characters progress to greater capabilities, some may become involved in warfare. I'm discussing this for the benefit of those GMs and game designers who want their world to make sense. Keeping the numbers down may also help when you're trying to fight out a battle on the tabletop in a campaign.

Army Inflation​

Many decades ago, I recall being in awe as I read about one of three Battles of Panipat (India) involving 600,000 men according to accounts of the time. The numbers were repeated in a 20th century dictionary of battles, yet sounded immensely inflated. They were, as are the claims from ancient and medieval times for many other battles. Logistics (supply, more or less) limits the size of pre-"modern" armies. In order to feed them and their horses, you can only concentrate so many in one place (not counting cities that have developed long complex supply chains, though few cities exceeded the size of armies in pre-modern times). Modern estimates for any of the three Battles of Panipat are for less than 150,000 total combatants in the 18th century battle, less than 100,000 for each of the older battles, not 600,000.

I find that counting, or relying on someone else to count, helps solve many questions; but even the commanders of pre-modern armies didn't know how many troops they had. So we resort to other methods.

Let's take some examples of battle sizes.

The Battle of Hastings and Marathon​

In the late 19th century, estimates for the size of armies at the Battle of Hastings (Norman conquest of England) were around 25,000 each. Today as we understand circumstances better, estimates are typically 6,000-8,000 per side. Not a big battle, but huge in its results.

Numbers cited for the Battle of Marathon (490 BCE) by the ancients are wildly unreliable. A method used by modern historians to try to achieve a reasonable range, was to compare the size of the (excavated) Persian camp to the size of other camps where numbers are fairly well known (as in the past few centuries, or some Roman camps). The Persian camp couldn't possibly accommodate anything like the numbers cited.

Another way to estimate number of participants is to know the number of men manning a ship. Greek and Persian triremes were quite standardized, and we know their size from excavating sheds where triremes were stored. If we know that the complement was typically 200 men, we can calculate that 371 ships (reported in detail by Herodotus for the Battle of Salamis) equals 74,200 Greeks. A similar logic can be applied to Viking armies, but here many historians distrust the number of ships reported by contemporaries, so we end up with estimates varying from hundreds to thousands.

Yet I still see wildly inflated numbers from works of the time repeated in modern day historical books.

Barbarian Invasions​

How about numbers of "barbarians" in ages of invasion? We have almost no reliable numbers. One that is reliable is the number of Vandals (with some Alans) crossing from Iberia to Africa, because the Romans (who transported the Vandals to participate in a civil war in Africa) had to know how many ships they needed. I've seen 80,000 quoted by historians, including women and children. Which likely meant no more than 20,000-25,000 warriors.

The Battle of Towton​

What may have been the bloodiest battle ever fought on English soil, the Battle of Towton (1461), involved 50,000-65,000 men counting both sides - about 1-2% of the population of England at that time!

Modern Battles​

Even in Napoleonic times, when roads were much improved and the supply system was designed to cope with large armies and rapid movement, the concentration of more than 100,000 on a side was quite rare, and confined to later in the war (Borodino, Leipzig for example)

The bloodiest battle of the American Civil War (Gettysburg) involved less than 100,000 on either side. The largest number of one side in any battle was Chancellorsville (133,000 Union). These were three and four days battles, not a single day, in times when railroads made supply immensely easier.

Contrast this with notions/claims of many hundreds of thousands in much more primitive circumstances. Such high numbers simply aren't possible, nor was there any way for contemporaries to know actual numbers.

Armies in Your Campaign​

When you run an RPG campaign involving warfare, you don’t generally need to get into details of latrines, camp followers, and pay, but you might want to recognize the difficulties involved in moving and maintaining very large numbers of troops. Most warfare in the melee age was “small war” that involved hundreds rather than thousands, and rarely tens of thousands let alone hundreds of thousands.

I used to live in “Battle Creek” Michigan. That eponymous “battle” involved all of . . . three men (no deaths). A castle could be held by less than a hundred men, unless the attackers were highly motivated and very numerous.

My advice is, forget the vast numbers and focus on interesting interactions.

Your Turn: What are the most numerous armies that have ever actually fought out a battle on the tabletop in your campaign?

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Lewis Pulsipher

Lewis Pulsipher

Dragon, White Dwarf, Fiend Folio


Rotten DM
I learn long ago that D&D is not the system which support army battles. I have sat on my military cook self a few times when playing in other people worlds, where we were basically playing Generals and Dragons. So ONE is my answer and it was in the DDAL09-20 Session When Devils Fear to Tread module.

I do recommend if you going to do Armies, you hack an Avalon Hill game. Maybe Tactics 2. You have your regular D&D session and then break out the board game for the army battles.


Possibly the largest battle of the ancient world modern historical consensus accepts was the battle of Cape Economus, with roughly 150,000 combatants on each side.

Personally, I've not had D&D morph into a war game since I was in college, as the time required to devote to that sort of campaign just hasn't come up. I believe the largest battle we tried to run involved some 85,000 troops total - 50,000 attackers against 35,000 defenders.

Generally speaking, most D&D settings are "points of light" style with large cities and relatively depopulated rural areas. If they aren't, then the author tends to want to be quasi-historical and realistic and so either way you tend to end up with fairly believable army sizes for the scale of the regions involved in the conflict.

Running large combats is a chore even if you adopt some sort of wargame as your resolution mechanism, you also still have to deal with character scale units interacting with the board ("heroes") in a way most wargames don't as leveled characters and large monsters are units in their own right.


B/X Known World
I’ve liked war in D&D for decades. So large scale battle are a thing that happens regularly. The two best ways to handle them, I’ve found, is to either go with Verdy’s Free Kriegsspiel or what’s now known as the Fate fractal, use the refular rules and stat blocks for D&D as the stats for armies of 100 or 1000, whatever scale you want really. Keep everything on the same scale and you’re set. For different sized armies use multiple stat blocks. If your scale is 1000:1 then 1000 orcs is one orc stat block and 2000 goblins is two goblin stat blocks. Etc.
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I directed the 12-part adventure path War of the Burning Sky, and despite the name, the party is only involved with armies on a field two times. They escape a besieged city being bombarded by wyvern cavalry, join up with other refugees fleeing to a safe haven, find shelter in another city that's under a naval blockade, and only in the fourth adventure end up fighting alongside masses of other soldiers on an open field.

After that are missions of diplomacy and spycraft and sabotage and rescue, and even street-to-street guerrilla fighting to drive out invaders. But then in the final adventure, the PCs are given the option of directing battalions in a grand clash of armies during a battle that lasts several days. Even then, though, the actual gameplay is more "here are some high value objectives the PCs undertake, and they can choose whether to get backup in them, or to have their armies deal with some of them on their own."

Real world armies never had 20th level PCs to contend with.
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Good article.

One last point I would make is that the smaller the battle, the more easily the PCs can influence it, so there are not just historical but also gameplay reasons to try to keep the numbers smaller/more realistic.

If you want to get crunchy -- and I mean really crunchy -- the old Rolemaster supplement War Law got into the real details of recruiting, training, deploying, and maintaining an army, and did so with a healthy dose of realism. It could handle pretty much the largest battles you'd have in a fantasy setting.


If I'm doing a D&D mass battle, it's probably just background dressing. Never had the quantity of miniatures to be able to do the likes of Battlesystem, and the paper chits were annoying to work with (and not visually appealing).

We did do a mass battle using the mob rules for the end of our Saltmarsh campaign (about a year ago). Looking at the spreadsheet I used, each side had about 200 combatants total.

Definitely have run bigger armies than that in the likes of Warhammer Fantasy Battles, Runewars and the like - but nothing of that scale in actual D&D games other than as backdrop.


When I've done battles, the PCs are assigned to special forces. Defend a critical pass, try to take out the enemy's dragon, act as reinforcements for failing battalions, counter the enemy's special forces. Bite sized encounters sometimes using mob rules for enemies, sometimes more typical encounters, sometimes just "hold ground" encounters where they can't win but the longer they hold off the enemy troops the better.

But it's good to know reasonable army sizes just for descriptive purposes.

I'd be very curious to meet the folks who blanch at fantasy army sizes that are consistent with reported army sizes from other historical battles (even if those reports may be inaccurate).

It'd just be interesting to meet someone so well versed in fantasy military logistics, historical military logistics, and current archeological methods and evidence that they would confidently question the reported particulars of an army size in their fantasy roleplaying game.

Maybe this is a wargamer thing?

From my perspective, where the fantasy breaks down is when the described visual size of the army diverges from the reported numbers in a "not big enough/that's way too big" kind if way.

When the 10,000 man army "spans as far as the eye can see all the way to the horizon",

or "the column is 10 miles long" etc..

I go..

"waitaminute.. 10,000 people can fit in one half of a hockey stadium, and we can all get to our cars in 20 - 30 minutes at a brick pace without bumping into each the hell is that army taking up so much space??"

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