The BEST way to estimate damage without a calc
TL:DR
Designing a system for mental calculations led me to discover a new and powerful method for thinking about and comparing mons’ defenses and damage output. And it’s pretty simple!
Why?
The obvious question is “why not just use a calc?” Realistically, you are better off using the calc if you actually want to know a specific damage roll midgame.
With that said, there’s actually a lot of cool stuff you can learn from designing a system like this! I was really surprised at how feasible mental estimation is, and it produced a system that provides a great way to compare pokemon.
Basic Idea
The core of the estimation is knowing two numbers: Bulk, associated with a given pokemon’s defenses, and Power, a value that combines the base power of a move with a mon’s attack.
Let’s say we’re in a Lando-T mirror match, and I want to know how much my Stone Edge will do. We’re both 252Atk and uninvested defensively. This spread has a Physical Bulk of 6.9 and its Stone Edge has a Power of 3.3. Dividing Power by Bulk (3.3/6.9 ≈ 0.48) tells us that this move will do at most slightly under 50%, and at least around 40%. This is a simple fraction that’s easy to estimate well in your head! (with a little practice, at least). The calc agrees with us:
252 Atk Landorus-Therian Stone Edge vs. 0 HP / 0 Def Landorus-Therian: 130-153 (40.7 - 47.9%) -- guaranteed 3HKO
Even better, damage percentages barely change at level 50, so this estimation also works in VGC!
Bulk and Power Values
I’ll go over how to generate Power and Bulk values later. Here’s how they’re used:
For a mon with a given spread, each of its moves gets a Power value based on the mon’s actual Atk/SpA value and the move’s BP. The association would be something like “Band (252+Atk) Scizor Bullet Punch has a Power of 4.5”— a specific move on a specific set.
Bulk is just based on the set, ignoring moves. Each set has a Physical Bulk and a Special Bulk value based on the mon’s HP and the relevant defensive stat. The association would be “Bulky (252HP) Lando-T has a Physical Bulk of 8.3”.
And those examples tell us that the Scizor would do 45-55% to Lando or any other mon with around 8.3 Physical Bulk!
To perform a damage estimation with the values, estimate Power divided by Bulk to get the base damage percentage, then apply stat boosts, effectiveness, etc.. STAB should already be factored into Power and shouldn’t be considered.
This gives you the maximum possible damage percentage; the random damage can lower the percentage by around 10%, so that will give you the range.
(The actual change is variable, but 10 gives a good estimation. Importantly, a move needs to deal 118% (before random damage) to OHKO, and 59% to 2HKO, so 120 and 60 are good benchmarks.)
(If you want specific percentages for any number, it’s 15% of whatever your damage is, so around 5 at 30%, 7.5 at 50%, 10 at 66%, 12 at 80%, and 15 at 100%.)
An example with Offensive (252Atk) Lando-T Earthquake (Power 4.9) vs. Specially Defensive (248HP/8Def) Toxapex (Phys Bulk 10.3):
Base Percentage: 4.9/10.3 ≈ slightly under 50%, maybe 48
Modifiers: Super Effective -> 48 * 2 = 96
Random Damage: 96 - 14 = 82
So our final spread is around 82-96. The calc agrees:
252 Atk Landorus-Therian Earthquake vs. 248 HP / 8 Def Toxapex: 246-290 (81.1 - 95.7%) -- guaranteed 2HKO
Calculating Bulk and Power
Power and Bulk are pretty simple to get.
Power is Atk * BP * 0.84 * STAB / 10000, where Atk is the relevant attacking stat unmodified (not the base stat), BP is the base power of the move, 0.84 is a constant from the damage formula, and STAB is 1.5 if the move gets STAB. The number is rounded to the nearest tenth, or preferably the first two significant digits. Dividing by 10000 just makes the number nice and small— easy to remember and work with.
Example: 252Atk Lando-T Earthquake
Atk = 389
BP = 100
STAB ✓
389 * 100 * 0.84 * 1.5 = 49014
Divide and round to 4.9
Bulk is even simpler— just Def * HP / 10000, where Def is the relevant defensive stat and HP is the HP. Again, these are the actual stats and not the base stats of the mon, and it’s rounded to the tenth.
Example: 252HP 252+Def Alomomola
HP = 534
Def = 284
534 * 284 = 151656
Divide and round to 15.2
Additionally, I’d recommend factoring in any stat change or ability that you expect to always affect the damage given/taken. A few examples:
Life Orb (bonus 1.3 multiplier to any move’s Power)
Adaptability (use 2 for STAB instead of 1.5)
Intrepid Sword (1.5 multiplier to Power)
Choice Band (1.5 multiplier to Power)
Vessel of Ruin (1.33 multiplier to Special Bulk)
Assault Vest (1.5 multiplier to both Bulks)
Drizzle, and so on.
It’s easy to get Power and Bulk values with a handheld calculator or to make a spreadsheet that calculates them for every mon. (I may make something like this eventually, though it’s quite easy to do on your own).
I’d recommend writing bulk values like this in conversation: “Great Tusk has a bulk of 11.1 / 5.3 uninvested”, i.e. 11.1 Defensive Bulk and 5.3 Special Bulk.
The obvious limitation of this system is that it requires you to generate the Power and Bulk values beforehand. This is what makes it mostly obsolete for mid-battle calcs— if you can refer to a precomputed spreadsheet, you might as well just look at a calc.
However, as I detail in the final section, it’s pretty enlightening to learn (or at least look at) the bulk values for a bunch of pokemon. It’s also worth knowing the power of a few key moves, just as a point of reference. Once you interact with the system a little, you’ll end up accidentally remembering a lot of bulk values the same way you probably remember base stats.
A Word About VGC
I’m not familiar enough with VGC to say if this is practical to use for it, but people expressed interest while I was working on this. If knowing a damage calc within 5-10% would be helpful, then this system can give you that calc in 5 or 10 seconds of thinking.
With level 50 pokemon, the damage calc will be off by at most 1-2%, which is negligible. Use the same Bulk and Power values (generated based on stats at lvl 100) regardless of the actual level of the pokemon battling.
It’s actually possible to mentally calculate the stats of a level 50 mon with only addition knowing its base stats and investments, but that’s a story for another time…
Further Applications
Even without memorizing anything, it’s pretty easy to get a feel for what different Power and Bulk values mean. Understanding these actually turns out to be super useful and powerful—
Because every pokemon with 8 Bulk will take the same percentage of damage from a 3 Power move (before modifiers), Bulk ends up being a fantastic tool for comparing pokemon quantitatively.
A pokemon with 5 bulk will take twice as much damage from any move as a pokemon with 10 bulk!
Ever wonder how much bulkier Great Tusk is than Lando? Or how much survivability you’d gain from fully investing into Defense? Looking at their Bulk values can give an exact answer.
Uninvested Great Tusk: 11.1 / 5.3
Uninvested Lando: 6.9 / 6.3
252HP Lando: 8.2 / 7.5
252HP 252+Def Great Tusk: 17.2 / 6.1
252HP 252+Def Toxapex: 13.5 / 9.7
Uninvested, Great Tusk is significantly bulkier physically than Lando, taking around 40% less damage per hit. However, it’s slightly weaker specially.
Investing into defense raises Tusk’s Physical Bulk to an unbelievable 17.2! That’s a huge increase and turns it into one of the bulkiest mons ever— most pokemon would take more than double the damage Tusk receives from any physical attack.
Or what about Chi-Yu’s famous Fire Blast? How does that compare to, say, Gholdengo’s (potentially boosted) Rain?
252+SpA Specs Ruin Chi Yu Fire Blast: 13.4
252+SpA Gholdengo Make it Rain: 6.1
+2 252+SpA Gholdengo Make it Rain: 12.2
252+SpA Specs Ruin Tera Fire Sunny Chi Yu Fire Blast: 26.5
So this goldfish, which has 252+SpA, Specs, STAB, and Beads of Ruin, does a whopping 13.4— enough to OHKO anything with a Special Bulk lower than 13 (that doesn’t resist it). (Though of course, random rolls mean mons at 12 or 13 can sometimes survive).
Gholdengo’s regular Rain isn’t even close, but after a Nasty Plot (just multiplying the regular Power by 2), it’s pretty comparable!
And of course, the Tera Fire in Sun nuke is in a class of its own. This will OHKO even resisting mons with Special Bulks under 13!
The objective comparison of different pokemon’s defenses is where I think the most value lies. Being able to have a number for a mon that’s so much more useful than its base stats— that immediately tells you exactly how much damage key moves would do to it, or how much more damage the same move would do to a different mon— gives you such a powerful tool of comparison for understanding pokemon defensively (and offensively!).
This could give a much firmer intuition of the strength and defenses of mons when teambuilding. What the heck is, like, Altaria’s Brave Bird going to do against key threats? Calculating its power tells us that it’s 2.7, so it’ll do about as much as an Offensive Great Tusk’s Knock Off (2.9 (first hit)). That’s around 25-30% to anything with a Physical Bulk of ~8.0, like Bulky Lando or Glowking!
Values for Power and Bulk could easily be attached to a PokePaste or Strategydex infobox to give additional info about the capabilities of a set.
Using this comparison system only requires calculating some values for moves and mons you’re curious about to get some intuition for what the Bulk values mean. It’s pretty quick to learn!