Size of an army vs total pop.

[Laharal]

Hello fellow playgrounders,
I'm asking myself questions regarding a standard or optimal % of the adult population which could be drafted in (fantasy/dnd/medieval) army without damaging too much the economy.

DMG p.99 A city typically has full-time military personnel equal to 1% of its
adult population, in addition to militia or conscript soldiers equal
to 5% of the population. The full-time soldiers are city guards responsible
for maintaining order within the city, similar to the role
of modern police, and (to a lesser extent) for defending the city
from outside assault. Conscript soldiers are called up to serve in
case of an attack on the city.

What if the army is made to attack? Defend an ally? etc. etc. Do I raise the % to 7 or 10% or would those numbers be too unrealistic?


That guy claims 7% max but has no sources

http://www.writing-world.com/sf/hordes.shtml

What do you say?

Many thanks

P.S. How much of a said adult population would be unfit for duty due to illness/too skilled to sacrifice/ cloistered monks etc?

[polity4life]

Consider looking at real-world census data and some data concerning wars.

Let's take Vietnam from the American perspective. Between 1965 and 1973, there were an estimated 1,728,344 men drafted (I say estimated due to the source). The average population for America during that time period was about 203 million people. That means less than 1% of the total population was drafted from the average population of that time period. Of course, the draft doesn't draw from the entire population. There are exclusions to consider.

Let's get the ratio of draft eligible people. At the time, it was only men. Gender is almost always a 50-50 split in America, so you have 102.5 million men. I can't recall the age rules of the draft for Vietnam but let's say 18-44 were eligible ages (I only use that range because census data I'm seeing has a convenient age bracket for that group).

According to these census data for 2000, 79.7% of all men were between ages 18 and 44. Now let's see what percentage of the male, draft eligible population is against the total male population using what we have above.

We have 203,000,000 as a total population. 50% of that is 102,500,000: our male population. 79.7% of males were ages 18-44, giving us a male, draft eligible population of 81,692,500. As stated earlier, the estimated draft total for the war in that time period was 1,728,344, meaning 2.1% of the male, draft eligible population was drafted.

It's not necessarily specific but it gives an idea of what a modern, industrialized country raised for a war. There are other circumstances baked into this example that we shouldn't discuss but perhaps these numbers can give you some idea as to what to expect.

EDIT: Fixed some math errors.

[Saithis Bladewing]

Varies heavily, but in a typical feudal european-style or east asian-style society, your average army size is not going to be very high. Economics dictate that spread out rural societies are harder to tax, individual income rates tended to be low to begin with, and most people were too busy living on subsistence work to actually be taken from their jobs for long or in large numbers.

The population of England in 1066 varied somewhere between 1 to 3.5 million, depending on sources and experts, and King Harold Godwinson was able to bring 15,000 men to fight the Battle of Stamford Bridge. He raised this in a hurry and I believe it's thought he had more men available during the spring and summer, but that they had to be sent back to the fields and villages due to economic and harvest restrictions. Still, he produced anywhere from 0.42%~ to 1.5%, depending on how high it goes. Assume an average of the two, i.e. 2.25 million, and you still only get 0.66%~ of the population in military service. The King is said to have had up to 5000 housecarls there (most optimistic estimate) i.e. full-time military soldiers in his host, which is 0.14 to 0.5% of the population (or 0.22% on average) in professional soldiery. That's 1 in 200 men as professional soldiers at most. Any number of the rest could be drafted, with varying effectiveness, cost and dissent from the populace.

To take a High Middle Ages (nearly Renaissance) estimate (more accurate to D&D tech levels, especially if you account for magic), the French army at the start of the Hundred Years War (1337) has been estimated anywhere from 30,000 to 65,000 men, from a population estimated at 20.2 million. That's a mere 0.14% to 0.32% of the population, probably including most of the realm's knights. This is even smaller, but France was renowned for its terrible taxation rates and disorganized bureaucracy.

Comparing this to Ming China at its peak, the population hovered around roughly 100 million people, with the army at its largest staffing 1 million men - almost exactly 1% of the population (and not counting its enormous navy, which may well have been almost as large at its peak, with the Battle of Lake Poyang recording 850,000 chinese sailors on both sides!). Assuming that was the largest the Chinse Navies ever got, that'd be 1.85% of the army involved in military service. It's worth noting, of course, that China was extremely advanced and wealthy during this period, but it was only a little more technologically advanced than Europe economically speaking, and worse militarily speaking.

So yeah, the pre-industrial age had considerably lower rates than the modern estimates above - but that should give you a nice high vs. low range to work with. Also this includes a statistically insignificant number of women, which may not be indicative of a fantasy setting's often more egalitarian culture.

[Eloel]

We have 203,000,000 as a total population. 50% of that is 102,500,000: our male population. 79.7% of males were ages 18-44, giving us a male, draft eligible population of 8,169,250. As stated earlier, the estimated draft total for the war in that time period was 1,728,344, meaning 21% of the male, draft eligible population was drafted.


Wait, what?
100+ million men, 80% eligible, 8 million eligible?
I'm not following.
(and have nothing useful to add)

[Saithis Bladewing]

Wait, what?
100+ million men, 80% eligible, 8 million eligible?
I'm not following.
(and have nothing useful to add)

I think he meant to tack an extra 0 onto that. Also it's important to note that draft eligible is not necessarily drafted, as to draft the entire male population would be economically unfeasible in more ways than one.

[polity4life]

Wait, what?
100+ million men, 80% eligible, 8 million eligible?
I'm not following.
(and have nothing useful to add)

Bah! You caught me. That's an obvious error.

81,692,500 eligible resulting in 2% actual. Herp derp. Thanks for pointing that out.

[Saithis Bladewing]

The highest mobilization rate that I know off the top of my head is the US in WW2, which raised 16 million personnel (men and women included) out of an estimated maybe 135 million people, or 11.8% mobilization rate. Worth noting that not nearly all of those are fighting men, though, many are in support roles (lots of women in that position) while medieval records wouldn't really have recorded the camp followers.

EDIT: Note that all of this is for /field armies/ which is a very different thing to an emergency mobilization of a city. You could probably call up most if not all the men for a city battle, but how many you could afford to pay and more importantly EQUIP is a completely different matter.

[Alejandro]

This has already been touched on, but a large factor is "What time of year is it?" If we are talking a quasi medieval society, wars were generally not intensively fought in the time period leading up to, and during, the harvest season. After the harvest was over, many able bodied men were then more available for soldiering.

[Logic]

The current US population is approximately 3.14 314 million.
The current number of people serving in the US armed forces (both genders) is about 1.5 million, with an additional 1.5 million in the Reserve components of their respective branches. That means about .5% is actively in the military, with an additional .5% ready to be called up at a moments notice.

Including the approximate currently draft eligible statistics is problematic, because while the draft is an option, it has to be authorized by congress, and it covers only males from ages 18-(38 I think) and training any of these draftees would take a minimum of 3 months before they were capable of being employed for military activities.

[Coidzor]

The current US population is approximately 3.14 million.
The current number of people serving in the US armed forces (both genders) is about 1.5 million, with an additional 1.5 million in the Reserve components of their respective branches. That means about .5% is actively in the military, with an additional .5% ready to be called up at a moments notice.

Including the approximate currently draft eligible statistics is problematic, because while the draft is an option, it has to be authorized by congress, and it covers only males from ages 18-(38 I think) and training any of these draftees would take a minimum of 3 months before they were capable of being employed for military activities.

Sorry, but something's not adding up here. 1.5 million + 1.5 million should be 3.0 million which is much greater than 1% out of 3.14 million.

[Alejandro]

The US population is 311 million people.

[Logic]

Sorry, but something's not adding up here. 1.5 million + 1.5 million should be 3.0 million which is much greater than 1% out of 3.14 million.

Yup, US population is 314 million. Oops.

[Zen Master]

Does anyone anywhere have even the slightest clue how large a part of all mongols saddled up to go with Ghengis and conquer every damned thing?

Somehow I guess horses was their real limitation. Not big on infantry, Ghengis.

[Talyn]

Using the United States, or even Medieval France, may not be a good model for comparing army size to population - a typical world of D&D is unbelievably hostile, packed to the brim with monsters and marauding hostiles.

A better comparison might be Israel - a heavily militarized modern state that is more or less constantly threatened by attack. The Israeli military has approximately 600,000 personnel (both active and reserve) out of a population of about 8 million. That's about 8% of the total population - and that's before taking into account that somewhere between 30 and 40% of their population is available for conscription and can provide their own weapons and uniforms on short notice.

On the other hand, modern Israel also a) uses modern agricultural techniques which don't require that 3/4 of the population be working on a farm, and b) imports a lot of their food and weaponry. Neither of which would be really viable for a quasi-medieval D&D world, though some of the higher-magic ones might be able to have such an economy.

[Gwyn chan 'r Gwyll]

Another great mobilization was Canada in either world war.

WWI
0.9% of the population died in combat.
That's not the size of the army.
That's not the size of the casualties.
That is DEATHS per person.

In WWI, we had a population of 7.2 million, 620,000 mobilized. That's 8.6% of the population mobilized, 0.9% dead, 2.4% wounded.

In WWII, we had a population of 12 million, with 1.1 million serving in uniform, this time including more women. That's 9.1% of the population serving a direct military role on of one sort or another.

For an intensely mobilized population, one in a constant life-or-death, pinpoints-of-light situation, this can be a good guide-line.

[darksolitaire]

It would seem that finland few years ago takes the cake with 530,000 grunts (http://en.wikipedia.org/wiki/Continuation_War) out os meager population of 3,695,610 (http://en.wikipedia.org/wiki/Demographics_of_Finland). That's like, 14,3% or something. Since then we have improved to 66% of male population (http://en.wikipedia.org/wiki/Conscription_in_Finland).

[ObadiahtheSlim]

As long as the army is back in time for harvest, you could probably draft a larger portion of the population.

[Dead_Jester]

North Korea, with it's more or less enforced conscription for both males and females, has I believe the current largest per capita military size, with something like 5% of the population in active military duty; however, if we consider the reserve forces, it rises to between 35 to 40% of the total population (female conscription more or less doubles your available service population).

[Elm11]

It would seem that finland few years ago takes the cake with 530,000 grunts (http://en.wikipedia.org/wiki/Continuation_War) out os meager population of 3,695,610 (http://en.wikipedia.org/wiki/Demographics_of_Finland). That's like, 14,3% or something. Since then we have improved to 66% of male population (http://en.wikipedia.org/wiki/Conscription_in_Finland).

Bugger. I've just finished a major study in Finland, and was thinking 'Gee, I'll never be able to use any of the knowledge I've gained doing this, even if it's an extraordinary achievement!'

'What's this? My God, someone asking about conscription rates, and the highest mentioned figure is the US! Now is my chance to shine, I can finally mention Finland and its --- Damnit.'

[darksolitaire]

Bugger. I've just finished a major study in Finland, and was thinking 'Gee, I'll never be able to use any of the knowledge I've gained doing this, even if it's an extraordinary achievement!'

'What's this? My God, someone asking about conscription rates, and the highest mentioned figure is the US! Now is my chance to shine, I can finally mention Finland and its --- Damnit.'

I actually feel bad about it now :smallbiggrin: It's not like we fins lurk around the internet, trying our best to find some place to mention our country, right?

[Aotrs Commander]

As long as the army is back in time for harvest, you could probably draft a larger portion of the population.

That's the limitation - wars are won, in the end by supply and logisitics.

Looking at the provided link to Finland, it says 66% of the male populace undergoes military service (i.e. have some basic training) - that's not quite the same as being able to actually mobilise 66% all at once, though. (For one thing, you need some reserves to replace combat losses.) I don't know how much military material Finland keeps at operational readiness (or in mothballs for same), but I would expect that it might struggle to properly outfit (and supply with ammunition), what roughly a third of the entire population all at once without some serious lead-time to prepare and build-up some stores. (But I could be wrong.)

(It's still quite an achivement to be proud of, however.)

Another point to note is, depending on what period you are, you may not field your whole army at once any (modern armies, that function twenty-four hours, only have about a third of their troops in combat at once, the others resting or being refuelled/repaired). A fantasy army may be more or less, depending on whether they function at night or not. And there is also the factor of considering how much of your support and ancillery personal come out of your army size (it'll be a significant number, whatever.)

[Elemental]

One must also factor in the fact that different societies can afford to send more to war.
It all depends on how the economy is based and where the war is fought.
If it's fought at home, you can call upon the vast majority of the populace and they would likely be willing to fight also. But if it is in some distant corner of the world, then a smaller army is substantially easier to field.

Thus echoing the point of a previous individual:
Wars are won by supplies and logistics, not numbers.

[Emmerask]

1917:
23% of the male population of the Russian Empire had been mobilized, numbering about 19 million. However most of these were not equipped with any weapons and had support roles maintaining the lines of communication and the base areas.
If we take a rough estimate of male female ratio of 50:50 then its 11.5% of the total population

[Alejandro]

Does anyone anywhere have even the slightest clue how large a part of all mongols saddled up to go with Ghengis and conquer every damned thing?

Somehow I guess horses was their real limitation. Not big on infantry, Ghengis.

A large portion of the Mongol army was not Mongol. The Mongols would often "make an offer you can't refuse" where your country/fief/empire/whatever could become part of the Mongol Empire, and your troops become part of its army, or they would raze everything and kill everyone.

[Elm11]

That's the limitation - wars are won, in the end by supply and logisitics.

Looking at the provided link to Finland, it says 66% of the male populace undergoes military service (i.e. have some basic training) - that's not quite the same as being able to actually mobilise 66% all at once, though. (For one thing, you need some reserves to replace combat losses.) I don't know how much military material Finland keeps at operational readiness (or in mothballs for same), but I would expect that it might struggle to properly outfit (and supply with ammunition), what roughly a third of the entire population all at once without some serious lead-time to prepare and build-up some stores. (But I could be wrong.)

(It's still quite an achivement to be proud of, however.)

Another point to note is, depending on what period you are, you may not field your whole army at once any (modern armies, that function twenty-four hours, only have about a third of their troops in combat at once, the others resting or being refuelled/repaired). A fantasy army may be more or less, depending on whether they function at night or not. And there is also the factor of considering how much of your support and ancillery personal come out of your army size (it'll be a significant number, whatever.)

While your statement about logistics and supplies governing wars is definitely the rule, there are definitely exceptions, particularly in ancient history. The one that springs to mind is the (Though really, there are several) Peloponnesian war/s. In these, the Athenian Empire had, right through the course of the period, vastly superior logistical capabilities, supplies and income than their Spartan foes. Yet, they lost almost every single military engagement of the war, and were eventually brought to ruination by a foe that they should have been able to defeat rapidly and comprehensively.

[KuReshtin]

A lot of this also has to take into consideration the size of the opposing force.

If you have 100.000 available soldiers to dispatch, but your opponent only has an estimated force of 5.000, you wouldn't have to send the entire 100.000 to attack them. It would just be too overkill.

An attacking force of 7:1-10:1 could potentially end the war before it even started, by the sheer number of attacking force, as the survival of the defending force would be doubtful at best.

Again, for the economic and logistical cost of sending an army to war, the head of the military would have to make a decision and guesstimate how big an army they can get away with to win the war, but still not cause too much of a strain on the economy.

[Aotrs Commander]

While your statement about logistics and supplies governing wars is definitely the rule, there are definitely exceptions, particularly in ancient history. The one that springs to mind is the (Though really, there are several) Peloponnesian war/s. In these, the Athenian Empire had, right through the course of the period, vastly superior logistical capabilities, supplies and income than their Spartan foes. Yet, they lost almost every single military engagement of the war, and were eventually brought to ruination by a foe that they should have been able to defeat rapidly and comprehensively.

That was because Athens badly mismanaged their operations (up to and including making one of their top general defect to the Spartans - while he was leading a major military operation - which is an occurance sufficiently uncommon I can't think of another instance off the top of my head), especially the debacle of the aforemention Sicilian Expedition which was sufficently catastrophic as to be the deathknell to Athas' power ten years later. (The final blow being dealt by the equally catastropic defeat at Aegospotami.)

Perhaps I should have said "the correct use of logistics and supply is what wins wars in the end." In that case, Athens didn't.

(Or perhaps even "while logistics and supply is what wins wars in the end, poor generalship is what loses it.")

[Elm11]

That was because Athens badly mismanaged their operations (up to and including making one of their top general defect to the Spartans - while he was leading a major military operation - which is an occurance sufficiently uncommon I can't think of another instance off the top of my head), especially the debacle of the aforemention Sicilian Expedition which was sufficently catastrophic as to be the deathknell to Athas' power ten years later. (The final blow being dealt by the equally catastropic defeat at Aegospotami.)

Perhaps I should have said "the correct use of logistics and supply is what wins wars in the end." In that case, Athens didn't.

(Or perhaps even "while logistics and supply is what wins wars in the end, poor generalship is what loses it.")

Yeah, I'll pay that. The correct management of logistics and supplies can lead to a war that should be an absolute curbstomp being something completely different. Take, for instance, the Finns (again) during the 1939-40 Winter War. The Finns, despite their army being outnumbered by roughly 10:1 by the forces deployed against them (more than 35:1 if you count the entire Russian Army) held out for more than 100 days against the USSR, dealing unbelievable damage to their opponent. One of the major reasons was because of how brilliant Mannerheim (and his subordinates, of course) was in the management of Finnish logistics, as compared with the haphazard approach taken by the Russians.

For those interested: The Winter War (http://en.wikipedia.org/wiki/Winter_War)

[ObadiahtheSlim]

Plus Stalin had killed most of his veteran officers. Without a competent corps of officers, you are fighting an uphill battle.