Last Updated on January 22, 2023
In Dungeons & Dragons 5th edition, Challenge Rating, or CR, is the numerical system used to determine a party of four players’ difficulty in defeating an enemy. Of course, there is a little more to deciding which fights you or your players might succeed in, but CR is the very basics of calculating battle difficulty. Challenge Ratings 5e range from 0 to 30 and include 1/8, 1/4, and 1/2 ratings.
Challenge Rating 5e is often an overly simplified system, so it shouldn’t be treated as a be-all-end-all determination of whether or not players can handle a situation. As always, defer to your intuition as a DM as to whether or not the fight needs to be scaled up or down. Improperly balanced parties, for instance, one with no healing spells, may not stand up to an enemy with a lot of long-term damage capabilities.
Table of Contents
How To Build Encounters Using CR
The CR of each creature is given to us, so an encounter’s CR is simply the sum total of the creatures’ CRs. Whether this is higher, lower, or equal to our party’s average level is what determines the difficulty.
Of course, this is based on a simple one-encounter-per-day calculation, and that’s not quite reality. The best process of calculating CR for encounters should actually use awarded XP for more accuracy, and should be as follows:
- Determine XP thresholds of individual party members.
- Add up each player’s XP threshold to determine the party’s.
- Find the total of the monsters’ XP
- Multiply the total XP by the encounter multiplier.
- Compare the encounters adjusted XP against the party’s threshold to determine difficulty
XP Awarded Based on CR
In order to understand any of the calculations we’re doing here, you have to know how much XP, or experience points, a creature awards players upon defeat. This information is shown in a creature’s stat block, but I’ve also put together a table showing you the XP awarded based on CR.
Player XP Thresholds Per Day
A monster’s CR determines how much Experience or XP they grant, and each character has a budget of XP that they can reasonably handle per day. The following chart gives the adjusted XP budget for a character per day, based on their level.
So if I have a party of four 1st level characters, they have an adjusted XP budget of 1200 (300 + 300 + 300 + 300), so I can use this as a template to determine what kind of monsters to throw into their encounters. But it’s more than just a numbers game of the total. An Almiraj is CR 0 and gives 10 XP, but if I throw 120 Almirajs at them… they’ll die (and I will die in real life trying to keep up with an encounter with 124 creatures in it.)
To break it down, 120 Almirajs will probably each get in about one attack before they die. That’s 120 attacks. About five percent of those will hit since a natural 20 always lands. Assuming the players average out to about 14 AC overall (with mages being lower and melee classes being higher), the Almirajs have approximately a 60% hit chance (The formula for chance-to-hit is: ((21 – (Target’s AC – Attack Modifier)) / 20 * 100), and the damage is at least 4.
We’ll say this is a well-balanced party with David the wizard, Mary the Sorcerer, Bob the Cleric, and Alice the Barbarian. That’s 52 health at level 1 if they all have maximum Constitution. The Almiraj’s only need to hit 11% of their attacks to achieve a TPK on round 1.
Luckily, Wizards has our backs for this one. They’ve also broken the game down into per encounter thresholds for XP. So you can determine the best way to get your party their maximum XP without killing them!
Player XP Per Encounter Thresholds
The XP Per Encounter Thresholds are precisely what’s written on the tin. They tell the DM how much a player can handle in a single encounter rather than throughout the day.
This table is based on an expected day of 5e adventuring, which includes at least one short rest and three or more encounters.
As the table suggests, it tells you what kind of encounters will pose the best challenge for your parties. I generally try to give my parties encounters in the medium to hard zone, but I do have one party that enjoys the challenge of taking on deadly and above encounters.
So using this, we can tell that the 120 Almiraj encounter is way too much for Bob, David, Alice, and Mary. When we add our party’s individual thresholds together, we can see that a medium encounter should yield 200 xp.
Okay, so we can’t send 120 Almiraj at our party, but we can do 20, right? Not quite, there’s still a bit more to factor in..
Encounter Modifier
When you add monsters to an encounter, you make the encounter more difficult. Very simply, more monsters means more chances that damage can be dealt, we’ve already seen this math play out with our ridiculous 120 Almiraj encounter..
To better calculate an encounter’s difficulty, we need to apply modifiers to the encounter based on the number of monsters we’re throwing at our players.
Using the modifier, even our ‘reasonable’ 20 Almiraj encounter has an XP yield of 800, making it a deadly encounter for even a party of level 2 characters.
Fortunately, this makes it very easy for us to figure out a nice balance. If we’re looking for somewhere between a medium and hard encounter, we’re aiming between 200 and 300 XP. Seven Almiraj would be appropriate then (7x10x2.5=210).
And of course, the big secret here, CR 0 creatures aren’t designed to be much more than pests, so most encounters we plan won’t go any higher than six creatures.
Encounter Balancing Calculators
The topic of Encounter Balancing has spurred several calculator applications to appear online to ease the process of encounter balancing for DMs. These tools are perfect for newer DMs who will need more help with balancing encounters. We’ve compiled a list of online calculators that you can use to
Kobold+ Fight Club
One of the most popular D&D encounter balancing websites is Kobold+ Fight Club. The previous Kobold Fight Club calculator is down, but this is a replacement version of that. Kobold Fight Club allows you to add characters and monsters to a list and even track their current HP values to see how deadly the encounter has become!
D&D Beyond
D&D Beyond has its encounter builder within the website. The feature is currently in Beta, so expect to see more features added to the tracker in the future!
Kastark
Kastark features an encounter balancing app as well as an initiative tracker on their website. It’s a bit bare-bones compared to Kobold Fight Club and D&D Beyond, but it’s much easier on your computer or phone when running it!
Balance an Encounter by Modifying CR
There are tons of ways to modify a creature’s CR, even in the heat of a battle. Whether it’s bumping stats, granting Legendary actions, giving multiattacks, or changing the dice on some damage values, there’s no shortage of ways to scale fights up and down .
When the Fight Is Too Easy…
If you find that your players are just decimating everything you put before them, don’t be afraid to scale up the fight. There are many ways you can do this within the confines of Wizards’ D20 system.
Fudging the Dice
The simplest way to modify an encounter’s difficulty is to start fudging enemy rolls in their favor. By allowing the enemies to hit slightly more often than the actual odds would allow, the encounter becomes significantly more challenging, even if the enemies themselves haven’t changed at all!
Add More Enemies to the Encounter
A lot of encounters come down to a simple game of numbers. Increasing the amount of enemies is an easy way to bump up the challenge rating of an encounter.
You can even do this in the midst of an encounter. If your enemies aren’t putting up the fight you expected, have an enemy summon reinforcements! Players will have to account for new sources of damage and new enemies on the map.
Remember, as the encounter goes on, your players, especially spellcasters, will have fewer and fewer resources to lean on, which also steadily increases the difficulty.
Give the Enemies More HP
Making enemies harder to take down, by giving them more HP, is a simple way to increase the longevity, and therefore, the difficulty, of an encounter.. We don’t want an encounter to last so long that it’s unbearable, but we can give the enemies enough time to put our heroes in danger.
When the Fight Is Too Difficult…
End the Fight
You see this a lot in video games. A fight that seems unwinnable is suddenly ended by some sort of intervention. This could be another character saving the players, a natural phenomenon, an enemy general calling their forces back, or any number of spontaneous events. Often, capturing the heroes by knocking them all out is a great way to end a fight without a TPK.
Fudge the Rolls
If your encounter ended up more challenging than you anticipated, you can fudge some rolls in favor of your players. Lower the monster’s saving throws and attack rolls to make your players feel like they have an upperhand. .
There are a couple things to be aware of here. First, you want to make the change subtle enough that your players don’t feel like you’re throwing the fight. This isn’t a game of Candyland at grandma’s house.
Second, fudging the rolls too much can lead to an annoying stalemate. If no one is hitting, the battle just gets boring, and it’s time to go back to some sort of intervention anyways.
Weaken the Enemy
If you don’t want to fudge any rolls, you can do more work behind the screen to weaken the enemies. Dropping their HP, removing abilities, or simply lowering the amount of damage they can deal are all simple ways to bring your characters closer to victory.
There are even ways you can do this and still achieve a level of storytelling, if you really want to strive for reality.You could have the enemy incur some kind of curse, have their armor or weapons break, or even have them be injured by a player’s attack and suffer a weakening effect from it.
Inaccuracies of the Challenge Rating System
The Challenge Rating 5e system isn’t without its flaws. It doesn’t take team composition, individual spell lists, item composition, or things like environmental factors into account when calculating how difficult something is.
Inaccuracies within the Challenge Rating 5e system will be felt hardest by teams of characters who have an unusual composition. I personally feel the weight of the CR system’s flaws because my players tend to enjoy running fun, unique compositions that the CR system just can’t account for — and I enjoy running those types of games.
I run a game that takes place in an Elvish Wizards’ school using the 5e system. Naturally, all the player characters are Wizards. At 1st level, my players were able to drop a CR 2 Priest in one round because of their incredibly great damage output, losing only one player (though he was killed in one hit.)
Individually, the Priest was highly deadly to the players. Against a party with less damage output, he would be equally fatal. But Wizards pack some of the most incredible low-level damage in the game. So his squishiness became readily apparent after he was slapped in the face with four first-level spells in a row.
My more standard party of a 6th level Warlock, Druid, Fighter, and Sorcerer were actually able to hold their own against a 20th level Barbarian NPC, though not without copious amounts of struggling.
Challenge Rating 5e is not the ultimate sign of strength. An intelligent party or an unusual combination of classes might take down a stronger enemy or have more trouble with a weaker one. For instance, a single Silence spell can easily take down my Wizard party, and a high-burst, long-range caster would take out my standard party without trouble.
How to Calculate CR for Homebrew Monsters
The rawest truth is that calculating CR for your homebrew monsters will be hard because Challenge Rating isn’t even remarkably accurate for official Wizard’s content. CR doesn’t take anything besides level into account. It would help if you came up with a CR to ensure your monster block has a proficiency score.
Wizards CR Table
Wizards provided a CR table that gives approximate statistics for a monster of any Challenge Rating. These statistics show the Challenge Rating for a monster’s Armor Class, Hit Points, Attack Bonus, Damage Per Round, and Save DC.
But there’s a bit more to the formula than just taking the numbers directly from the table. Using the table, you can calculate your monster’s CR by taking the averages of its actual stats. Using this method, an enemy has two CR ratings, an offensive one and a defensive one.
Defensive CR
Firstly, we’ll look at calculating a Monster’s Defensive CR. That is how easy it is to kill. The defensive CR is found by taking the average of the CR indicated by its HP and its AC.
So if we start with a monster with 150 HP, that’s CR 6, but if its AC is only 13, then its Defensive CR is three or: (6 + 1) / 2, rounded down.
Offensive CR
Offensive CR is similar. You take the CR indicated by the Damage Per Round and their Attack Bonus and average them, just like your Defensive CR, but with offensive stats.
So if we give our monster a DPR of about 46 and an Attack Bonus of 3, that evens out to a CR of 4 or (7 + 1) / 2, rounded down.
Final CR Calculation
So now that we have the offensive and defensive CR calculated, we can calculate our CR by taking the average of the offensive and defensive CRs. So our monster’s CR is 3 or (4 + 3) / 2, rounded down. There are a few more considerations to make, though.
CR Multipliers
Several multipliers are added onto the Challenge Rating based on other factors like resistances and other features which affect the battle.
Flying & Ranged
If a monster is both flying and has attacks that can hit from long range, its effective AC is increased by 2. When you calculate its Defensive CR, you should use the increased AC to calculate.
Saving Throws
Saving Throw proficiencies also affect a monster’s effective AC. All monsters can have 1 or 2 saving throw proficiencies without changing their CR. If it has 3 or 4 proficiencies, increase its effective AC by 2. If it has 5 or 6 proficiencies, increase its effective AC by 4.
Feats, Racial Traits, & Monster Traits
There are many feats, racial traits, and monster traits that can affect the Challenge Rating of a monster. The Dungeon Master’s Guide contains a list of features a creature might have and how that affects their Challenge Rating calculation.
Any racial traits granted to the monster will be the same as a player character’s block.
CR Calculation Applied in Real-Time
To best illustrate the use of the Challenge Rating calculation, we will build a monster together! I’ve got to put together a boss monster for my Wizard School campaign, and there are lots of things to consider on that axis because of the unusual nature of the campaign. So, it’s an excellent place to apply all of our theories.
Our party is going to be 1st level Wizards, still, because they’re still in school! So we have to account for the fact they all have 8 hit points and will drop like flies if we give too much damage to this monster. But because they’re all Wizards, if the boss has too little HP, he’ll also drop like a fly.
They also come preloaded with four hirelings that are also 1st level Wizards (because it’s a university, and of course, they have boyfriends and girlfriends like university students often do.)
So we’re building a monster for a party of eight 1st level Wizards. We also need to remember that they don’t have a healer because they’re all Wizards. Their “healing” is killing the enemy, so they can’t take damage.
With these in mind, our expected Defensive Challenge Rating needs to be in the CR 2-6 range, while our Offensive Challenge Rating needs to be in the CR 0-1/2 range. Anything that hits harder than a CR 0-1/2 monster will drop them instantly, while anything with defenses lower than a CR 1 monster will pretty much melt immediately.
In this particular situation, the best offense is a good defense. These kids are low-level Wizards. So they come armed with a few really good hits and then sort of just faffing around with cantrips. If we can get through that first round, we put them on the defensive because they’ve got such limited spell slots at level 1.
We’ll give our boss 105 hit points, way more than is expected from a low-level mob. We need him to soak up that early damage, but we don’t want him to be oppressive. We’ll give him an AC of 14, a little bit higher than low-level, but again, not overpowering. He doesn’t fly naturally, and even if he transforms into a flying creature, he wouldn’t be able to cast spells or make ranged weapon attacks while doing it. He also doesn’t have more than two saving throw proficiencies.
After all calculations and considerations, this gives him a defensive CR of 4, smack dab in the middle of our expected range.
He’s a powerful druid who will be poisoned with a weakening potion that brings him down to the level of our protagonists. So let’s give him a DPR of 3 and an attack bonus of 5 to reflect his former power. This gives him an Offensive CR of 0.625 (about 2/3), which is a little bit higher than we expected.
This mean’s he’s got an aggregated Challenge Rating of 2 or (4 + 0.625) / 2, rounded down.
We will have to count in that he’s immune to necrotic damage, though. So his final CR is 4 or (2 × 2), rounded down. Whether or not my players will be able to handle that… well… we’ll see. I’ll have to get back to you on that.
CR Calculators
If you don’t want to do all that math by yourself, never fear! There’s plenty of CR calculators that you can use online to calculate the Challenge Rating of your homebrew monsters!
Brohannes Brahms’s 5e Homebrew CR Calculator
This CR calculator features both a quick calculator and a full-scale calculator accounting for
/u/ItsADnDMonsterNow’s CR Calculator
This is one of the most comprehensive Challenge Rating calculators on the web. It accounts for the stats and adds modification for things like Legendary Resistance, feats, and racial traits! It’s very customizable and works great for anyone looking to balance their game meticulously!
Conclusion
Challenge Rating is a very complex subject and a critical part of homebrew campaigns and settings. Whether you calculate your Challenge Rating manually or use a calculator, getting the hang of the system will improve your DM and player experience! Good luck, travelers!
