For one of my campaigns I'm running I'm wanting to do a pitched battle of sorts, like a 100 v 100 sort of affair. The problem I'm running into is that there are going to be a lot of attacks, especially considering that each combatant is generally capable of attacking more than once. The PC's are very strong (beyond 20th level) however, and they can soak a lot of damage from many of these enemies without being killed.

My question is, what is the best way to model this combat? I can't really handwave most of it out as they will be interacting with the PCs.

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    \$\begingroup\$ Have you tried the "rules for mass combat"? \$\endgroup\$
    – nitsua60
    Jan 16, 2017 at 2:23
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    \$\begingroup\$ possible duplicate: rpg.stackexchange.com/q/88741/23064 \$\endgroup\$
    – daze413
    Jan 16, 2017 at 2:43
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    \$\begingroup\$ @daze413 I'm conflicted on the close-vote because this post doesn't have the very-troublesome "what are interesting ways you've done this" formulation of the linked post. Withholding judgment for the moment. \$\endgroup\$
    – nitsua60
    Jan 16, 2017 at 2:49
  • \$\begingroup\$ @Raznarok If the linked question answers your own, would you mind if we closed this one as a duplicate? I am also conflicted in closing this as a duplicate to a closed question. Perhaps it should be the other way around? \$\endgroup\$
    – daze413
    Jan 16, 2017 at 2:55
  • \$\begingroup\$ @daze413 I'm open to narrating the parts of battle that the players aren't directly in. So if it was like 1000 vs 1000 I wouldn't roll for what happened on the flanks if the players were in the middle, I would just narrate what happened. I'm just torn about the center itself, since the players will end up being attacked by a lot of enemies each turn. \$\endgroup\$
    – Razmode
    Jan 16, 2017 at 3:17

8 Answers 8


There are basic rules for this in the DMG (pg 250)

Instead of rolling an attack roll, determine the minimum d20 roll a creature needs in order to hit a target by subtracting its attack bonus from the target's AC. You'll need to refer to the result throughout the battle, so it's best to write it down.

Look up the minimum d20 roll needed on the Mob Attacks table. The table shows you how many creatures that need that die roll or higher must attack a target in order for one of them to hit. If that many creatures attack the target, their combined efforts result in one of them hitting the target.

For example, eight orcs surround a fighter. The orcs' attack bonus is +5, and the fighter's AC is 19. The orcs need a 14 or higher to hit the fighter. According to the table, for every three orcs that attack the fighter, one of them hits. There are enough orcs for two groups of three. The remaining two orcs fail to hit the fighter.

I personally have used a similar system back to 2nd edition. As stated in the other answer, you simply calculate the percentage chance to hit, multiply by number of monsters, and multply by avg dmg.


C= Chance to hit/100
M = number of monsters
D = avg dmg per monster A = number of attacks per monster

Total monster dmg to PC per round = C x M x D x A

The fighter can still only hit as many mobs as attacks per round. You could either give your player the choice to roll, or also calculate avg mobs killed per round:

C = chance to hit monster/100
A = number of PC attacks
D = avg dmg per attack
MH = Monster hit points
N = Number of enemies(of the monsters) in range
NMA = Total Number monster attacks

Monsters killed / round by PC =MIN(A , MIN( N, C x A x D / MH))

Enemies killed / round by monsters =MIN(NMA , MIN( N, C x NMA x D / MH))

In other words, the minimum of number of attacks, number in range, and number killed.

  • For number in range, unfortunately, you have to just guestimate as the fighter can move from enemy to enemy. I would say 5, so number of attacks is probably limiting factor.
  • Finally, you can do x rounds at a time, by multiplying the above by x, but you also have to multiply the A, NMA, and N by x in the min equation.
  • If you end up with 0.5, that means it takes two rounds to kill one enemy.
  • If the fighter gets critical on 18,19, etc, just increase chance to hit by 5% for each crit slot (assuming a crit basically does damage as another attack).
  • You will want to group similar creatures together to make this easier.
  • Here "monster" is used as "mob," an enemy of the PC (which might actually be a human). "Enemy" is used as an enemy of the monsters(who might actually be humans.)
  • See https://rpg.stackexchange.com/a/94076/33272 for info on advantage/disadvantage.
Hopefully someone just has Meteor Swarm though.

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    \$\begingroup\$ So not rolling any dice, but just taking the average damage and scaling with the number of monsters? \$\endgroup\$ Jan 16, 2017 at 12:28
  • \$\begingroup\$ @Trilarion basically, yes. The formula shows what would be the expected result after rolling several thousand dice. \$\endgroup\$
    – Chepelink
    Jan 16, 2017 at 12:55
  • \$\begingroup\$ This post intersperses mob (as in 'an unruly mob', Total mob dmg per round) and mob (as in gamer speak for mobile enemy, The fighter can still only hit as many mobs...). Very confusing. Would be improved if that latter was replaced with enemies. \$\endgroup\$
    – Wyrmwood
    Jan 17, 2017 at 18:18
  • \$\begingroup\$ You might want to eliminate the slang use of “mob” completely from the post. Used to mean “enemy” or “monster”, it is a common term in video game fandom, but not in roleplaying game communities. The only use that appears in D&D is the “a large group of normal people” meaning. Using “mob” to mean anything else, especially after quoting the normal meaning of mob from some D&D text, is likely to cause confusion rather than be a useful bit of shared slang. \$\endgroup\$ Jan 21, 2017 at 0:27

Focus on the PCs

You might find it interesting to model an entire war-like scenario with hundreds of attacks on either side, but this will ultimately get boring for the players. Focus instead on the conflict immediately around the players, and relegate the rest as you see fit: either a dice roll, coin flip, or simply improvised narration without rolling the dice.

With that being said, there may still be tons of attacks being rolled. You can further simply these attacks by using average damage for enemy attacks rather than rolling, and by borrowing from previous editions rules for "mooks," giving each enemy a single hit point, so that you don't have to track hitpoints for anything, except perhaps bosses or generals.

  • \$\begingroup\$ I see what you're saying. So for average damage, say 15 mooks are attacking a PC. Is this link kind of what you are talking about? highprogrammer.com/alan/gaming/dnd/statistics/weapondamage So each mook would do ~5ish damage? \$\endgroup\$
    – Razmode
    Jan 16, 2017 at 2:57
  • \$\begingroup\$ The attacks within a monster's stat block include it's average damage on a hit. It should say something like 5(1d6+2), where the 5 is the average for the dice roll within the parenthesis. \$\endgroup\$ Jan 16, 2017 at 3:02
  • \$\begingroup\$ Ah, thats useful. Whats the best way to calculate the average damage for a homebrew monster? \$\endgroup\$
    – Razmode
    Jan 16, 2017 at 3:10
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    \$\begingroup\$ That probably belongs as its own question rather than a discussion in comments. \$\endgroup\$ Jan 16, 2017 at 3:15
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    \$\begingroup\$ I second this. The boring part of the battle in movies is when the camera zooms out and sweeps over unnamed lackeys. The exciting parts are when the heroes are battling for their lives against the opposing champions / general. So zoom the action in. The rest of the battle is window dressing to their story. \$\endgroup\$
    – timje
    Jan 16, 2017 at 17:20

The method I have found that works best in my group is to establish a timeline of major phases of the battle. Do the math in advance and figure out exactly how the battle would unfold without the PC's help and then let the PCs change that timeline with their actions. Here I give a quick example of a town with a Town Hall, Keep, and Church. They are not very well prepared and will lose absolutely everything without the PC's help. In your situation, the Keep might stand or the Church might manage to hide people under it, etc...

Battle Phases

Phase 1:

The players see enemies coming from the woods. If they are wondering where they are heading, maybe a high check can guess that the Town Hall looks like a good target from where they're attacking. Ask the PCs what they're going to be doing over the next few minutes.

Let's say the PCs arrive at the Town Hall and a fireball completely wrecks the group attacking the town hall. When they see the church under attack, they could tell the Town Hall guards to head there, then head to the keep themselves.

In another situation, let's say the group takes too long at the Town Hall and get to the Church by Phase 5. When they arrive, the attackers would be inside the Church already, half the people might be dead, and there might be a situation where the PCs need to get in without letting the attackers kill off the people. This might delay them and give them a difficult choice when they simultaneously see attackers marching on the Keep.

Keep Going

Roll through the battle phase by phase instead of round by round. For the most part, you can hand-wave single combat. If they do end up in a battle with a really big group, you can use a system like @Ἄρτεμις described.

Speed Things Up

Speed things up by pre-rolling enemy rolls. Grab a generator online and pre-roll dice the enemy may use such as d20s, d6s, d4s, etc..., then save them into a spreadsheet. That way, if a player is up against 4 people attacking with d4 weapons, you can easily cross off the first 4 d20s and see how many hit, then cross off how many d4s hit off the d4 table.


There is an Unearthed Arcana article just for this purpose


This UA article describes rules you can use when staging a large battle. I have personally used them before and have to admit, they were much better than I was expecting on the first read through.

To summarise the article:

  • treat each monster as a group of 10+, using the same stats and attacks as the stat block

  • each round represents 1 minute and all actions are simultaneous

  • PC's and major NPC's count as Solos (individual characters)

  • slightly edited rules for actions, spell casting, etc

On first read, I found the formations and stances for a Unit a little confusing and overwhelming, but they soon fell into place when we actually placed the miniatures on the map and started playing. Each player had their own copy of the rules for quick reference and I, as DM, just double checked what they wanted to do so I could gauge their, and my own, understanding.


I recommend "Macro" Gaming. Describe the battle, utilize whatever system of dice roles you like. D20 or percentile work best, and describe to the players what their actions do as they perform over the course of minutes and hours in game. This takes as long as it is to discuss.

For example: One wizard says he goes to fight hordes of orcs from a nearby tower, the fighter offers to guard the entrance. If you deem the orcs attacking as too easy, but there will be lots of them, just describe their defense. No need to roll much. Let the players roll a few "combat like checks" to see how well they do.

Basically macro the game, do not play it round by round when dealing with large numbers.

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    \$\begingroup\$ Have you used this method? This answer could be vastly improved if you can describe how you've used it and how well it's worked for you? \$\endgroup\$ Jan 16, 2017 at 6:50
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    \$\begingroup\$ Sorry, this answer lacks detail. You need to actually describe something that you've tried and how it works. \$\endgroup\$
    – Eidolon108
    Jan 17, 2017 at 3:41

I've historically treated large mobs of people as old 3.5 swarms of sorts. They deal a guaranteed amount of weapon damage (the average proficiency of the "horde")d(average sized weapon die of the horde) every turn to enemies they are adjacent to. More damage (instead of rolling they just deal max damage) to enemies within them, and if using ranged weapons I treat it as either a line attack, a cone attack, or a ranged radius attack with some Reflex save for half damage that's affected by the group's average attack bonus. (The attack deals the amount of calculated weapon damage above)

Hit points equal to the average sized HD of the composite creatures * The number of creatures/5 usually. (I'd say change this per party composition and how hard they usually hit)

The "horde" has disadvantage to avoid effects that target areas. When at half life (treat as half total number of original individuals) they have to start making saves or break up and run.

Hordes of rogues get average sneak attack damage but only on enemies they encompass completely. And the sneak attack is rolled, as opposed to the max that the weapon die gets.

They don't ever crit so, while less damaging, its also less likely to completely total an individual player.

Its a little bit of an 'on the fly' method but I think it works decently.


I actually ran into this with my own group where I was caught between two "scopes:" too many combatants for every combatant to get a turn in the initiative, but for story reasons I needed the players to actually be in the midst of the combat taking actions as normal on a battlemap where each unit had its own token, which ruled out most mass combat systems.

What I ended up doing was similar to what would eventually be in Unearthed Arcana: When Armies Clash, but much simpler. I created what I called a "group." A group was a collection of NPCs/monsters that tended to operate together and had the same stat block. You can actually have melee and ranged fighters in the same group as long as they have the same attack and damage roll, but I prefer to break a mixed group up into an all-melee group and an all-ranged group.

The idea from then on is that whenever a character would make a single roll, the group makes a single roll. The group makes a single initiative roll and then the group acts on that round. Each member of the group moves up to its individual speed, and then the group as a whole makes a single attack roll. An attack against a group uses the same AC as the base stat block. So a group attacking a group is just a single attack roll against a single AC. Damage is a single damage roll multiplied by the amount of group members who are in position to attack (for example a group of 10 that has 8 who can make an attack and rolls 5 damage would deal 5*8=40 damage.) If the attack roll misses, apply damage the same but instead use the lowest possible damage roll instead of rolling it.

Instead of a damage pool, the group loses members. For every amount of damage = to the HP on the stat block, remove a group member from the board and thus from future attacks. Once all the "dead" group members have been removed just note the remainder until the next time the group takes damage: for example if a group that's based on a stat block with 12HP takes 40 damage remove 3 group members entirely (3*12=36) then apply the remaining 4 damage to reduce the groups "next death" HP to 8. The next time the group takes damage apply the first 8 damage points to remove the "wounded" group member and then apply as normal from there. When all the members are gone so is the group. You can roll dice to pick who dies but I usually just kill off whatever I think is appropriate. Healing is just the same thing backwards (heal the wounded guy back to normal, then the next point brings back a group member with 1 HP and then apply healing to get them back to full health, then the next point of healing gets another group member back and so on.)

Anyone not in a group just acts as normal. If a group's damage includes a non-group member, assign the damage roll multiplied by the number of group members who would reasonably be attacking that target, then apply the rest of the damage to the opposing group. A group taking damage from an AoE takes as much damage as the AoE damage roll multiplied by the number of group members affected, then apply that damage as normal. An attack that does enough damage to down multiple targets does so even the attack wouldn't normally.

The result is a system that works for the kind of battles I want when I run a scene like this: swingy battles of attrition where every single dice roll results in a loss of resources for one side or the other, where troops move in large and small formation and form visible battle lines, and but also one where I can adjudicate the action very rapidly with just my usual dice and a calculator. (You don't actually need the calculator, but it speeds up the game up immensely.) With a little practice (and the calculator) you can play out a whole battle in just slightly more time than a normal skirmish, if not sometimes less (it's easier to move 10 tokens and then make a single attack roll than it is to make 5 moves and 5 attack rolls.)

Mostly though, I use this system because my players love it. The battles feel like battles, there's not a lot of sitting around watching me do math even when it's a group attacking a group, and their character get to have a huge impact on the battle using their actual character abilities, especially the wizard and the fighter.

My only warning is to make sure that your decisions make sense in the context of the battle: it's trivially easy to down a PC by having every single member of one side target that PC, but what sense does that usually make? It works better if you spread the damage around more so it feels more like individuals are dealing with what's immediately in front of them and less like some over-arching hive mind is enforcing a strict kill order.

Hope it works or at least it gives you some ideas, and good luck.


I would recommend allowing the PCs to participate in a number of smaller skirmishes within the larger fighting. And then separate the larger fighting using more popular mass combat rules.

My recommendation would be to run a number of encounters with just the PCs and a smaller force and allow the outcomes of these skirmishes to act as modifiers for a mass combat encounter. Dealers choice on what mass combat rules to use, however. Rulesets are widely available and varied, so very much a personal preference. This preserves the PCs ability to affect the outcome while limiting the dicerolling that needs to occur. This is how I run any mass combat. Using a mass combat ruleset also allows you a little wiggle room to fudge the narrative, as your players won't likely be familiar with the rule set.

In essence, the players control their characters. You control everything else. Keep their interaction small and try to streamline anything that doesn't necessarily require their interaction.

  • \$\begingroup\$ Could you expand upon this answer a bit more? Have you done this or experienced someone else using this method? How well did it work? What are the "more popular mass combat rules" and where can I find them? It's important to "back it up," so answers should cite experience or other practical support of the concept. \$\endgroup\$ Jan 16, 2017 at 20:38

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