I'll be honest trying to calculate CR confuses me so just want help with a creature I'm homebrewing. It's a variant of the Shadow that I'm calling the Shadow Mage
For the SM I've removed the strength drain aspect & increased their health to 8d8+30 along with the following spells using Dex as the spellcasting stat
The Dungeon Master's guide is woefully limited in its advice on spells and how they affect challenge rating. (Going by 5.0/2014 guidelines here. 5.5's is even worse with guidelines overall.)
I'd say to think about "Okay, how will this monster act?"
For example if the plan is to cast Hunger of Hadar the first round and then Chill Touch the next two while keeping up Hunger and maybe using Counterspell once here's what I would do.
Hunger is 2d6 and 2d6. Use the AoE (like a dragon's breath weapon) to count that as 4d6 damage on two creatures. So 14*2 = 28 damage per round. Then chill touch for a 5th level spellcaster is 2d8 so 9 damage.
Now from spells over three rounds we have 28*3 + 9*2 = 88 = 18 = 106. Avg: 106 / 3 = 35.33
That gives you the base damage and then you get the spell attack/DC for any adjustments.
As for the defense, counterspell is tricky. But one approximation would be to consider it kinda like a legendary resistance. (So give extra effective hp based on legendary resistance guidelines.)
And with mirror image you'll trade off less damage but perhaps boost effective hit points by 50% (haven't done the math, but basically account for attacks hitting the duplicates instead of itself)
Entangle could be considered like Pack Tactics by restraining them giving you advantage so use that. Bane reduces their odds to hit so perhaps boost effective AC by 1.
So once you have ideas of "how does this order of casting spells affect CR" that'll help.
I would recommend you figure out how monster hit points work before you homebrew monsters. It is physically impossible for a monster to have 8d8 + 30 hit points because 30 isn't a multiple of 8.
For the Cr, a CR 6 mage is a 9th level caster, so a 5th level caster would likely be in the 2-4 range. It depends on spells though.
I'd eyeball it at around CR 4, but any time you're creating custom monsters, the actual CR is a lot less important than general modeling of an encounter to figure out how it would likely turn out.
HP = 62 (average number based on 8d8+30) This places it in CR1/2
Attack Bonus (also Proficiency) = +4 (assuming +2 PB that's a +2 attack bonus) This means a bracket of CR0-CR2
Damage Per Round (Average is 11dpr assuming Hunger of Hadar is up and a melee attack with a 1d6+2) This means CR1
I'd then place your design as explained at a CR1, maybe a CR2.
My Advice I think this is a common mistake that folks make. They don't take the time to consider that we've been given a really easy guide to use. If you're designing a monster, use the stats straight from the table in the DMG (2014).
It's a rough and ready way of doing things but just take a single line on the chart and design the creature to fall within that set of numbers. So, if I want to design a new creature I'll consider what level it's going up against. If I've got four level 2 player characters, I'll set them up against either four CR2 enemies, or one CR8 creature. Let's say then that I'm designing a CR2 enemy. This is how I go about it.
I'll look to the table I referenced above. The monster gets:
AC - 13
HP - 86-100
Attack Bonus - +3 Worth noting here that when creating an attack ability or spell casting ability I'll add the AB and PB to get the final number. So a melee attack will likely gain a +5 for this creature.
Damage per round - 15-20 I'd likely employ a multiattack ability here (ranged or melee) with the damage die being a d8. Two attacks that can both deal 1d8+5 are likely to have an average of 18 damage per turn if they both hit which falls nicely within the 15-20 range.
Spellcasting - Maximum of Level 2 spells which on average deal 5d10 damage if we go by the Create a Spell rules.
Spellcasting modifier - I'd usually simplify and have this be the same as the attack bonus plus proficiency bonus.
You can of course take a different tack. To do this you might decide that you're going to want something more highly armoured and choose something with a CR4 defensive rating, but a CR1 offensive rating by taking those figures from the table. This would even out at a CR2 creature but allows for a higher AC but lower damage.
This is just my interpretation of how the monster design using the CR tables is supposed to work. And of course, if you're playing 5.5e you're out of luck. The new DMG is an abomination...I'd highly recommend getting yourself a copy of the Tales of Valiant Gamemaster's Guide which makes the writers of the new DMG look incompetent. Their guidance for GMs does translate really well to 5.5e and is so much better than WotC's. In fact their new adventure setting is slated to come to D&D Beyond soon so there is compatibility between ToV and 5.5e. Kobold Press have done a stellar job in creating a book with more options and advice. They give you a full 34 pages of advice and even give you templates and examples of how those templates get modified. Like I say, makes WotC's team look incompetent in my opinion. It is a seriously great guide for how to create your own monster for 5.5e.
HP = 62 (average number based on 8d8+30) This places it in CR1/2
Attack Bonus (also Proficiency) = +4 (assuming +2 PB that's a +2 attack bonus) This means a bracket of CR0-CR2
Damage Per Round (Average is 11dpr assuming Hunger of Hadar is up and a melee attack with a 1d6+2) This means CR1
I'd then place your design as explained at a CR1, maybe a CR2.
Gonna nitpick you there since you're treating the HP/AC Damage/AttackBonus like they're two separate things to look at instead single units that go together.
You don't start with AC and also HP for defensive CR. Instead you take the 62 for hit points which puts you in the CR 1/2 row and then the AC 12 is not +/-2 away from the 13 in that column so you leave it there. Defensive CR: 1/2
Then for offensive CR it starts with the damage and you've got the 11 which puts you in the CR 1 row. Then the +4 attack bonus is not +/-2 away from the +3 of that row so no further adjustments. Offensive CR: 1
Then average is (1/2 + 1) / 2 = 1.5 / 2 = 3/4 round up to 1. CR 1 definitively.
EDIT: By the way where did you get 11 damage a round from? Hunger does 2d6 and 2d6. Are you assuming only 1 turn of Hunger working? (14 damage, doubled to 28 for multiple targets. And then 5 on R2 and R3. For 38 / 3 = 12.66? Not that it changes the CR calc in this case.)
Relevant section of the DMG
Defensive Challenge Rating. Read down the Hit Points column of the Monster Statistics by Challenge Rating table until you find your monster’s hit points. Then look across and note the challenge rating suggested for a monster with those hit points.
Now look at the Armor Class suggested for a monster of that challenge rating. If your monster’s AC is at least two points higher or lower than that number, adjust the challenge rating suggested by its hit points up or down by 1 for every 2 points of difference.
Offensive Challenge Rating. Read down the Damage/Round column of the Monster Statistics by Challenge Rating table until you find your monster’s damage output per round. Then look across and note the challenge rating suggested for a monster that deals that much damage.
Now look at the attack bonus suggested for a monster of that challenge rating. If your monster’s attack bonus is at least two points higher or lower than that number, adjust the challenge rating suggested by its damage output up or down by 1 for every 2 points of difference.
If the monster relies more on effects with saving throws than on attacks, use the monster’s save DC instead of its attack bonus.
In general I use https://www.blogofholding.com/?p=8469 for expected numbers for creatures of a given CR. This can easily be approximated as CR = (damage over 3 rounds + max HP) * 0.03, rounded down.
HP = 62 (average number based on 8d8+30) This places it in CR1/2
Attack Bonus (also Proficiency) = +4 (assuming +2 PB that's a +2 attack bonus) This means a bracket of CR0-CR2
Damage Per Round (Average is 11dpr assuming Hunger of Hadar is up and a melee attack with a 1d6+2) This means CR1
I'd then place your design as explained at a CR1, maybe a CR2.
Gonna nitpick you there since you're treating the HP/AC Damage/AttackBonus like they're two separate things to look at instead single units that go together.
You don't start with AC and also HP for defensive CR. Instead you take the 62 for hit points which puts you in the CR 1/2 row and then the AC 12 is not +/-2 away from the 13 in that column so you leave it there. Defensive CR: 1/2
Then for offensive CR it starts with the damage and you've got the 11 which puts you in the CR 1 row. Then the +4 attack bonus is not +/-2 away from the +3 of that row so no further adjustments. Offensive CR: 1
Then average is (1/2 + 1) / 2 = 1.5 / 2 = 3/4 round up to 1. CR 1 definitively.
EDIT: By the way where did you get 11 damage a round from? Hunger does 2d6 and 2d6. Are you assuming only 1 turn of Hunger working? (14 damage, doubled to 28 for multiple targets. And then 5 on R2 and R3. For 38 / 3 = 12.66? Not that it changes the CR calc in this case.)
Relevant section of the DMG
Defensive Challenge Rating. Read down the Hit Points column of the Monster Statistics by Challenge Rating table until you find your monster’s hit points. Then look across and note the challenge rating suggested for a monster with those hit points.
Now look at the Armor Class suggested for a monster of that challenge rating. If your monster’s AC is at least two points higher or lower than that number, adjust the challenge rating suggested by its hit points up or down by 1 for every 2 points of difference.
Offensive Challenge Rating. Read down the Damage/Round column of the Monster Statistics by Challenge Rating table until you find your monster’s damage output per round. Then look across and note the challenge rating suggested for a monster that deals that much damage.
Now look at the attack bonus suggested for a monster of that challenge rating. If your monster’s attack bonus is at least two points higher or lower than that number, adjust the challenge rating suggested by its damage output up or down by 1 for every 2 points of difference.
If the monster relies more on effects with saving throws than on attacks, use the monster’s save DC instead of its attack bonus.
So, even players are smart enough to move out of the space in which Hunger of Hadar is dropped. But sure, you could make the argument that a player is too silly to even have their character just pick a direction and run - Blinded doesn't mean player characters can't move. Just that they're not able to see. If they pick a direction and run it's likely that they'll get out of the area of effect. Players would have to be preternaturally stupid not to figure that one out. Especially as HoH doesn't move. If you assume such silliness on the part of players then, yeah that takes the average damage up by a whole 6 points of damage. It doesn't move the needle all that much, certainly not beyond the CR1 or CR2 level.
And as for the 'defensive' and 'offensive' elements, they're irrelevant to the overall point. Especially as they were all over the map in the original 'design'.
What I was trying to advocate for is a more simple design process. Simply pick a CR and give your monster stats that lie within that area. There's no need to overcomplicate matters by picking one set of Offensive stats and a set of defensive stats. Just make it simple.
So, even players are smart enough to move out of the space in which Hunger of Hadar is dropped.
The problem comes when doing so requires moving by more than your speed (20' radius of difficult terrain, mind you, and depending on the map you might not be able to escape in every direction), at which point... taking a few dice of damage may be worth it to avoid spending your action to dash.
If you look up ******** they do have a CR calculator but you do have to input the damage per round, hp, and some other details, so it would be good to make a roadmap of how you're gonna cast the spells
Rollback Post to RevisionRollBack
DM: He doesn't have much besides the skin on his bones.
Me: I'll take the skin on his bones, then.
Also, this is for Redwall nerds: Eeeeeuuuuulllllllaaaaaaaalllllllliiiiiiiiiaaaaaaaaa!!!!!!!!!!!!
So, even players are smart enough to move out of the space in which Hunger of Hadar is dropped.
The problem comes when doing so requires moving by more than your speed (20' radius of difficult terrain, mind you, and depending on the map you might not be able to escape in every direction), at which point... taking a few dice of damage may be worth it to avoid spending your action to dash.
Oh the point is taken, and granted my assumptions are coloured by my experiences with players. Even then though, we're really splitting hairs here and showing why CR is so tricky and imperfect.
For me the answer is in simplifying the process - hence my advice to simply read the CR line you're attempting to hit and giving your new monster stats within that range. It's not for every DM, but it is my suggestion
I'll be honest trying to calculate CR confuses me so just want help with a creature I'm homebrewing. It's a variant of the Shadow that I'm calling the Shadow Mage
For the SM I've removed the strength drain aspect & increased their health to 8d8+30 along with the following spells using Dex as the spellcasting stat
The Dungeon Master's guide is woefully limited in its advice on spells and how they affect challenge rating. (Going by 5.0/2014 guidelines here. 5.5's is even worse with guidelines overall.)
I'd say to think about "Okay, how will this monster act?"
For example if the plan is to cast Hunger of Hadar the first round and then Chill Touch the next two while keeping up Hunger and maybe using Counterspell once here's what I would do.
Hunger is 2d6 and 2d6. Use the AoE (like a dragon's breath weapon) to count that as 4d6 damage on two creatures. So 14*2 = 28 damage per round.
Then chill touch for a 5th level spellcaster is 2d8 so 9 damage.
Now from spells over three rounds we have 28*3 + 9*2 = 88 = 18 = 106.
Avg: 106 / 3 = 35.33
That gives you the base damage and then you get the spell attack/DC for any adjustments.
As for the defense, counterspell is tricky. But one approximation would be to consider it kinda like a legendary resistance. (So give extra effective hp based on legendary resistance guidelines.)
And with mirror image you'll trade off less damage but perhaps boost effective hit points by 50% (haven't done the math, but basically account for attacks hitting the duplicates instead of itself)
Entangle could be considered like Pack Tactics by restraining them giving you advantage so use that.
Bane reduces their odds to hit so perhaps boost effective AC by 1.
So once you have ideas of "how does this order of casting spells affect CR" that'll help.
This is a signature. It was a simple signature. But it has been upgraded.
Belolonandalogalo Malololomologalo Tumagalokumagalo, Sunny
Eggo Lass, Bone and Oblivion
Tendilius Mondhaven Paxaramus, Drakkenheim
Silverwood Group 1 | Silverwood Group 2 | Hacking the Hackett
Get rickrolled here. Awesome music here. Track 51, 10/23/25, Viva La Vida
I would recommend you figure out how monster hit points work before you homebrew monsters. It is physically impossible for a monster to have 8d8 + 30 hit points because 30 isn't a multiple of 8.
For the Cr, a CR 6 mage is a 9th level caster, so a 5th level caster would likely be in the 2-4 range. It depends on spells though.
I'd eyeball it at around CR 4, but any time you're creating custom monsters, the actual CR is a lot less important than general modeling of an encounter to figure out how it would likely turn out.
CR Calculations on your design
This places it in CR0 territory.
This places it in CR1/2
This means a bracket of CR0-CR2
This means CR1
I'd then place your design as explained at a CR1, maybe a CR2.
My Advice
I think this is a common mistake that folks make. They don't take the time to consider that we've been given a really easy guide to use. If you're designing a monster, use the stats straight from the table in the DMG (2014).
It's a rough and ready way of doing things but just take a single line on the chart and design the creature to fall within that set of numbers. So, if I want to design a new creature I'll consider what level it's going up against. If I've got four level 2 player characters, I'll set them up against either four CR2 enemies, or one CR8 creature. Let's say then that I'm designing a CR2 enemy. This is how I go about it.
I'll look to the table I referenced above. The monster gets:
Worth noting here that when creating an attack ability or spell casting ability I'll add the AB and PB to get the final number. So a melee attack will likely gain a +5 for this creature.
I'd likely employ a multiattack ability here (ranged or melee) with the damage die being a d8. Two attacks that can both deal 1d8+5 are likely to have an average of 18 damage per turn if they both hit which falls nicely within the 15-20 range.
You can of course take a different tack. To do this you might decide that you're going to want something more highly armoured and choose something with a CR4 defensive rating, but a CR1 offensive rating by taking those figures from the table. This would even out at a CR2 creature but allows for a higher AC but lower damage.
This is just my interpretation of how the monster design using the CR tables is supposed to work. And of course, if you're playing 5.5e you're out of luck. The new DMG is an abomination...I'd highly recommend getting yourself a copy of the Tales of Valiant Gamemaster's Guide which makes the writers of the new DMG look incompetent. Their guidance for GMs does translate really well to 5.5e and is so much better than WotC's. In fact their new adventure setting is slated to come to D&D Beyond soon so there is compatibility between ToV and 5.5e. Kobold Press have done a stellar job in creating a book with more options and advice. They give you a full 34 pages of advice and even give you templates and examples of how those templates get modified. Like I say, makes WotC's team look incompetent in my opinion. It is a seriously great guide for how to create your own monster for 5.5e.
DM session planning template - My version of maps for 'Lost Mine of Phandelver' - Send your party to The Circus - Other DM Resources - Maps, Tokens, Quests - 'Better' Player Character Injury Tables?
Actor, Writer, Director & Teacher by day - GM/DM in my off hours.
Gonna nitpick you there since you're treating the HP/AC Damage/AttackBonus like they're two separate things to look at instead single units that go together.
You don't start with AC and also HP for defensive CR. Instead you take the 62 for hit points which puts you in the CR 1/2 row and then the AC 12 is not +/-2 away from the 13 in that column so you leave it there.
Defensive CR: 1/2
Then for offensive CR it starts with the damage and you've got the 11 which puts you in the CR 1 row. Then the +4 attack bonus is not +/-2 away from the +3 of that row so no further adjustments.
Offensive CR: 1
Then average is (1/2 + 1) / 2 = 1.5 / 2 = 3/4
round up to 1. CR 1 definitively.
EDIT: By the way where did you get 11 damage a round from? Hunger does 2d6 and 2d6. Are you assuming only 1 turn of Hunger working? (14 damage, doubled to 28 for multiple targets. And then 5 on R2 and R3. For 38 / 3 = 12.66? Not that it changes the CR calc in this case.)
Relevant section of the DMG
Defensive Challenge Rating. Read down the Hit Points column of the Monster Statistics by Challenge Rating table until you find your monster’s hit points. Then look across and note the challenge rating suggested for a monster with those hit points.
Now look at the Armor Class suggested for a monster of that challenge rating. If your monster’s AC is at least two points higher or lower than that number, adjust the challenge rating suggested by its hit points up or down by 1 for every 2 points of difference.
Offensive Challenge Rating. Read down the Damage/Round column of the Monster Statistics by Challenge Rating table until you find your monster’s damage output per round. Then look across and note the challenge rating suggested for a monster that deals that much damage.
Now look at the attack bonus suggested for a monster of that challenge rating. If your monster’s attack bonus is at least two points higher or lower than that number, adjust the challenge rating suggested by its damage output up or down by 1 for every 2 points of difference.
If the monster relies more on effects with saving throws than on attacks, use the monster’s save DC instead of its attack bonus.
This is a signature. It was a simple signature. But it has been upgraded.
Belolonandalogalo Malololomologalo Tumagalokumagalo, Sunny
Eggo Lass, Bone and Oblivion
Tendilius Mondhaven Paxaramus, Drakkenheim
Silverwood Group 1 | Silverwood Group 2 | Hacking the Hackett
Get rickrolled here. Awesome music here. Track 51, 10/23/25, Viva La Vida
In general I use https://www.blogofholding.com/?p=8469 for expected numbers for creatures of a given CR. This can easily be approximated as CR = (damage over 3 rounds + max HP) * 0.03, rounded down.
So, even players are smart enough to move out of the space in which Hunger of Hadar is dropped. But sure, you could make the argument that a player is too silly to even have their character just pick a direction and run - Blinded doesn't mean player characters can't move. Just that they're not able to see. If they pick a direction and run it's likely that they'll get out of the area of effect. Players would have to be preternaturally stupid not to figure that one out. Especially as HoH doesn't move. If you assume such silliness on the part of players then, yeah that takes the average damage up by a whole 6 points of damage. It doesn't move the needle all that much, certainly not beyond the CR1 or CR2 level.
And as for the 'defensive' and 'offensive' elements, they're irrelevant to the overall point. Especially as they were all over the map in the original 'design'.
What I was trying to advocate for is a more simple design process. Simply pick a CR and give your monster stats that lie within that area. There's no need to overcomplicate matters by picking one set of Offensive stats and a set of defensive stats. Just make it simple.
DM session planning template - My version of maps for 'Lost Mine of Phandelver' - Send your party to The Circus - Other DM Resources - Maps, Tokens, Quests - 'Better' Player Character Injury Tables?
Actor, Writer, Director & Teacher by day - GM/DM in my off hours.
The problem comes when doing so requires moving by more than your speed (20' radius of difficult terrain, mind you, and depending on the map you might not be able to escape in every direction), at which point... taking a few dice of damage may be worth it to avoid spending your action to dash.
If you look up ******** they do have a CR calculator but you do have to input the damage per round, hp, and some other details, so it would be good to make a roadmap of how you're gonna cast the spells
DM: He doesn't have much besides the skin on his bones.
Me: I'll take the skin on his bones, then.
Also, this is for Redwall nerds: Eeeeeuuuuulllllllaaaaaaaalllllllliiiiiiiiiaaaaaaaaa!!!!!!!!!!!!
Oh the point is taken, and granted my assumptions are coloured by my experiences with players. Even then though, we're really splitting hairs here and showing why CR is so tricky and imperfect.
For me the answer is in simplifying the process - hence my advice to simply read the CR line you're attempting to hit and giving your new monster stats within that range. It's not for every DM, but it is my suggestion
DM session planning template - My version of maps for 'Lost Mine of Phandelver' - Send your party to The Circus - Other DM Resources - Maps, Tokens, Quests - 'Better' Player Character Injury Tables?
Actor, Writer, Director & Teacher by day - GM/DM in my off hours.