D&D 5E 9th level spells compared by equivalent lower level spell value

[Frankie1969]

Over in the survivor thread I had a silly notion and wanted to expand on it.

Basic Math:

• Mass Heal = 10x Heal 6.
• Mass Polymorph = 10x Polymorph 4.
• Meteor Swarm = depending on targets, from 5x Fireball 3 up to 80x Fireball 3 .
• Power Word Heal = small multiple of (Heal 6 + Greater Restoration 5).
• Prismatic Wall = Wall of Fire 4 + Wall of Ice 6 + Wall of Force 5 + Glyph of Warding 3 with (Flesh to Stone 6 + Plane Shift 7 + Acid Arrow upcast + something else).
• Storm of Vengeance = depending on targets, from 1/2x Storm Sphere 4 up to 324x Storm Sphere 4.

Weird Science:

• Astral Projection = Plane Shift 7 + Clone 8, sort of.
• Gate = Plane Shift 7 or (Contact Other Plane 5 with a chance of Conjure Celestial 20).
• Imprisonment = Flesh to Stone 6, but faster & more expensive.
• Invulnerability = 2x Stoneskin 4 + 10x Protection from Energy 3, sort of.
• Psychic Scream = 20x Staggering Smite 4, sort of.
• True Resurrection = Resurrection 7 + something.
• Wish = any spell 8,7,6,5,4,3,2,1,0 or Divine Intervention 50%.

Beats Me:

• Foresight = ???
• Power Word Kill = ???
• Shapechange = Polymorph + ???
• Time Stop = ???
• True Polymorph = ???
• Weird = ???

 

[Salthorae]

Beats Me:

• Foresight = ???
• Power Word Kill = ???
• Shapechange = Polymorph + ???
• Time Stop = ???
• True Polymorph = ???
• Weird = ???

Hmm, my thoughts on the "Beats me" section...

• Foresight = WIN
• Power Word Kill = Finger of Death (5) on steroids up to 100 hp
• Shapechange =1-600 Polymorph + no CR cap + not stupid
• Time Stop = WIN pt. 2
• True Polymorph = Finally you can match First Year Harry Potter students in Transfigurations... but also, like WIN pt. 3 if they fail their save or you need to turn that large pillar into a Cloud Giant or something.
• Weird = 1 - 72x Phantasmal Killer (4) depending on targets in 30' radius

 

[BlivetWidget]

Though this isn't exactly the angle you're going for, I feel like this is an appropriate place to put an analysis of spell power.

If we're going to compare the power of spells at level A with level B, the only sensible approach is to look at damaging spells (the utility of being invisible in a way that still allows casting or turning a friend into a giant ape is somewhat more difficult to measure). My first instinct was to look at the table on DMG p283, which proposes guidelines for creating custom spells. The table looks nice and neat, but comes with the rather significant issue that the game designers clearly did not come anywhere near to using the table when they made the spells in the rulebooks.

So I picked out some classic damaging spells of varying level. Fire Bolt, Magic Missile, Scorching Ray, Fireball, Vitriolic Sphere, Cone of Cold, Otiluke's Freezing Sphere, Crown of Stars, Sunburst, and Meteor Swarm. Average damage from the dice was calculated with a weighting factor of 1 for save for half and 0.75 for attack / save for nothing. The breakthrough was in finding DMG p249 (Adjudicating Areas of Effect) for the number of targets various AoEs could expect to hit and using that as the multiplier to find total damage from the spell.

The best simple equation I could come up with (obviously you could fit the data exactly with enough terms) was still actually pretty decent at predicting the power of canonical damaging spells: 6 * 2**level

Spell Level	Expected Damage Across All Targets (6 * 2**level)
0​	6​
1​	12​
2​	24​
3​	48​
4​	96​
5​	192​
6​	384​
7​	768​
8​	1536​
9​	3072​

The takeaway here is that each level is predicted to be twice as powerful as the previous level, but it's probably better to think of them as ranges. So a level 9 spell should be about 2x as powerful as a level 8 spell, but anything from 1x to 4x (non-inclusive terminus) would not be out of place. Similarly, a level 9 spell should be about 4x as powerful as a level 7 spell, but anything from 2x to 8x (non-inclusive terminus) could be justified.

Just a fun bit of math for you.

 

[BlivetWidget]

Addendum: In the spirit of your original post, let's say we want to duplicate Meteor Swarm with some apprentice mages using Firebolt. You'd need 20,462 of them. BUT... most of those are wasted shots, merely filling the air with fire where you expect to find it. The vast, vast majority of a Meteor Swarm's damage is "wasted" in that large area of effect. So going off the expected damage from the expected number of hits, using the above formula says you can get away with only having 512 apprentices and generally have the same end result. What a bargain!

 

[Frankie1969]

Firebolt is a single-target attack spell though. Mathematically, Meteor Swarm is 4 non-overlapping castings of Fireball, each with 5x damage and 4x area of effect.

 

[Coroc]

......

• Mass Heal = 10x Heal 6.
• Mass Polymorph = 10x Polymorph 4.
• Meteor Swarm = depending on targets, from 5x Fireball 3 up to 80x Fireball 3 .
• Power Word Heal = small multiple of (Heal 6 + Greater Restoration 5).
• Prismatic Wall = Wall of Fire 4 + Wall of Ice 6 + Wall of Force 5 + Glyph of Warding 3 with (Flesh to Stone 6 + Plane Shift 7 + Acid Arrow upcast + something else).
• Storm of Vengeance = depending on targets, from 1/2x Storm Sphere 4 up to 324x Storm Sphere 4...

.....

From the spell description of meteor swarm it says 20d6 fire +20d6 bludgeon save for half for each creature in one of the four 40 foot radius spheres you target. Overlapping areas add nothing to it.

That means a creature inside that sphere on average takes about 140 damage on a failed dex save and 70 damage on a successful one.

So how do you get 80 Fireball 3 out of it? Do you mean when fighting closed ranks of an army? Because that's about the only situation where you eventually would need 80 fireballs to cover the same size of area. Do you mean fireball cast reduced to 3rd level or cast at base level aka caster level 5? where is the bludgeoning component of that? Why would meteor swarm equivalent to 80 saves respective, if you would have overlapping fireballs you need multiple saves for some of the army? What's about spell DC?

This comparison is at least worded strange, since I consider myself not stupid and cannot quite comprehend your math. I consider it rather wobbly tbh.

 

[Frankie1969]

5x damage * 4x blasts * (2x radius squared) = 80x.
If you're facing hundreds of 100+HP creatures covering a large battlefield, then it would take 80 fireballs to do the same amount of damage.

 

[Ruin Explorer]

5x damage * 4x blasts * (2x radius squared) = 80x.
If you're facing hundreds of 100+HP creatures covering a large battlefield, then it would take 80 fireballs to do the same amount of damage.

I mean you say "if", but this is a totally implausible situation.

Especially the 100+HP bit - you just don't face those sort of numbers of 100+HP creatures in D&D. Even if you did, the vast majority of 100+HP creatures in D&D, especially ones that only occupy one 5' square, have defenses and special abilities which will degrade the utility of meteor swarm, and may in some cases negate it entirely.

Also if the DM is rolling initiative separately for the groups of 100+HP creatures there's a pretty much 100% chance one of them beats the wizard on initiative, and given there are dozens of them, and they probably have nasty ranged attacks because they're 100+HP and probably size M humanoids (so nasty buggers), the wizard will probably die rather than casting anything.

The only time this would be any valid would be like, carrying out a terrorist attack on a high-level undead convention or something.

 

[Frankie1969]

Shrug. Hypothetical but implausible maximum is what "up to" means.
A top-tier caster should be able to Meteor Swarm for 10x Fireball pretty often, and 20x in the right circumstances (4 teams of mid-CR enemies surrounding your party).

 

[Ruin Explorer]

A top-tier caster should be able to Meteor Swarm for 10x Fireball pretty often, and 20x in the right circumstances (4 teams of mid-CR enemies surrounding your party).

"Pretty often"? Unless you're deliberately provoking those kind of situations, that's going to happen like once or twice from level 18 to 20. If even that. It may well happen zero times. Really doubt that many casters will be able to use Meteor Swarm in an efficient way more than a handful of times in their career (the same is true for most 9th-level spells, to be fair), let alone the 10x-20x ultra-efficiency you're suggesting.

Plus, are these creatures morons who always lose initiative and have no idea what they're fighting? That seems to be the assumption here.