Thrill of the Spreadsheet: Understanding Multistrike

I've seen a few explanations of how multistrike affects your damage, and each time I was left a bit unsatisfied.  So, as perhaps can be expected at this point, I decided to try to give it a shot, and really spell it out as clear as I can.

Multistrike - gives most abilities up to two separate chances to hit their original target an additional time for 30% of the original amount in PvE. 

Just as a little side note here, to make things a little bit clearer, from this point forward, I'm going to refer to one of the 30% damage shots following your main shot as a "multistrike", and i'm going to refer to the stat as "MS" ("MS%" or "MS Rating").

The trouble in understanding that, is it doesn't really explain how much of a damage increase each % of multistrike gives you.  However, with a little bit of algebra, we can convert this to a bit simpler to understand function.  

To start off, the number of multistrikes you average per shot will be a simple function of the MS%.  If you have, for example, 20% MS, then you have have a 36% chance of getting at least 1 multistrike for any individual ability you use; that is to say, if you fire 100 arcane shots (which do 5000 dam each, we'll get to that later though), you'll get (on average) 36 of those to proc at least one multistrike.  In addition to that, you have a 4% chance of getting 2 multistrikes off of any individual ability.  So of those 36 multistrikes (proc'ed off of a hundred abilities), 4 of them will will have partners, bringing our total up to 40 multistrikes out of every 100 abilities. Of course, that's the same thing as saying you'll average .4 multistrikes per shot, if you have 20% MS.  

Then, because each of those multistrikes do 30% as much damage as the original shot, in our little example here we can go ahead and multiply that in there. If we have 100 arcanes doing 5000 damage each (500,000 damage total), and then we'll have 40 multistrikes which will do .3*5000 damage, that brings us 560,000 damage, a 12% increase in damage.   And that's the number we're really interested in.  For 20% MS, we get a 12% increase in damage.  

The function which explains that for any given MS% or ability's damage is:

Total Damage = (MS% * 2 * .3 * base damage)

Or  we can divide that all by the base damage if we're interesting in just the percent increase in damage:

Increase in damage = (MS% * 2 * .3 * base damage) / base damage

which can be simplified to a much easier:

Increase in damage = MS% * 3/5

In increments of 5% MS, that ends up looking like this:

MS % Dam. Incr.
20% 12%
25% 15%
30% 18%
35% 21%
40% 24%
45% 27%
50% 30%
55% 33%
60% 36%
65% 39%
70% 42%
75% 45%
80% 48%
85% 51%
90% 54%
95% 57%
100% 60%

For those who don't like to think in algebraic, the easiest way to understand that, I think, is looking at that last entry, with 100% MS.  It makes sense that 100% MS would give you 60% extra damage, since it will guarantee you 2, 30% extra damage shots. The point of all of this is, 1% MS gives you 3/5 % increase in damage.  

There is then, just one more number we need to look at when thinking about the stat: the amount of the stats on gear that it takes to make up 1%MS. As it's tuned currently on the beta (which seems likely to make it onto live, at this point), it takes 66 MS rating.  That means for every 66 MS you get a 3/5% increase to your damage.  For a 1% increase in damage, then, you'll need 110 MS rating, which is a somewhat interesting number, and not because it's the smallest number that's the product of two different substrings (just look it up), but because it's the exact same rating you need to get 1% crit (which much more conveniently, 1% crit happens to equal a 1% damage increase).

So basically, we have two stats which do the exact same thing.  This doesn't mean they'll be of equal worth.  Currently there are a few more mechanics which add benefits to crit; perhaps the biggest for hunters right now is the MM Aimed Shot, which returns 20 focus to you when it crits.  Another major effect on the value of the stats is the newly introduced Stat Attunements, which provide 5% more of the respective stats from gear.  There's also specs like Survival which has a basic, flat increases to Multistrike damage (for those interested, you get more stats from your gear, and you get 20% more damage per multistrike, so in the end you get 1% of MS from less stats, and instead of getting 3/5% damage increase per 1% MS, that extra 20% damage per multistrike gives you a total of .72% damage increase per 1% MS). *Edit* Thanks to dues payer and WHU member Jacques for pointing out that the 20% is not applied to the damage of the original shot, but to the damage of the multistrike.

The last thing I'd like to bring up (which I've already mentioned on this site, but I feel like it's worth reiterating) is that that Multi-strike is multiplicative with with the other secondary stats (except for perhaps haste).  What I mean by that, is if your arcane shot does 5k base damage, and you have 25% crit, and 25% multistrike,  your arcane shot will not average 7500 damage (which would be 5k + 5k*.25+5k*.25), instead, it's going to average 7812.5 (which is 5k*1.25*1.25).   This is because Multistrikes can Crit.  So Critical nets you more damage when paired with Mulistrikes, and vice versa.  This is also true of Versatility, and for hunter specs, Mastery (on applicable abilities).  

Anyhow, after writing this, I'm not sure if I've actually managed to make the subject any simpler, or if perhaps I've made it seem even more confusing.  Hopefully something in here will help someone, though.  


  1. This is an excellent explanation but being you are the math guy I will throw another question at you with concern to multistrike, one which I think is extremely important and will change the value of the stat, possibly a great deal. I can really use someone to put my mind at ease with it because I have tried figuring it out myself in make believe scenarios and my head explodes. Perhaps if you just tell me not to worry about it I will feel safe and stop thinking about it.

    Back to the description of multistrike and the words "most abilities". I find that extremely disturbing because (not just talking hunters here but the classes in general) it makes figuring out the exact value of multistike more a function of your rotation or the abilities you have to use depending on the fight in the case of healers and tanks and thus changing the value of multistrike under certain conditions.

    In the example you used you used an ability that does proc multistrike, arcane shot. So of course your numbers are perfect and your conclusions are concrete and can not be debated.

    But lets say there is an ability you use in your rotation, or two (remember talking for all classes) that can not proc multistrike. Lets say they are the 2nd and 4th button in a 6 ability rotation. That effectively lowers the value of multistrike, quite possibly a great deal depending on what 2 and 4 hit for.

    Now lets say at a certain haste point your rotation changes a little and now of your 6 buttons where 2 could not proc multistrike it is now 7 things where 3 can not, or 7 things were 2 can not. Being your entire rotation has changed based on your haste the effective value of multistrike changed didn't it? This is what I have been working on in my mind.

    It all seems way to confusing with "most abilities" procing it and I believe that no true real and completely accurate number will ever be able to be put on multistrike without complex mathematical refiguring every time you get a new piece of gear.

    Now, I am not sure if I explained what I was trying to get at or just confused you like I think I confused myself. But this has been a concern of mine since multistrike was first announced and we were told that not everything could multistrike. I think it makes the stat too mathy.

    1. I haven't tested any other class, but for hunters, at least, I haven't found any damage dealing abilities that don't proc multistrikes (on my logs at least, every ability, including pet abilities, had multistrike procs). So at least you won't have to worry about that with hunters.

      I was under the impression that what they meant by "most abilities" was that it wouldn't effect abilities like battle rez's (magically 30% rezzing a second player?), or other things like that that weren't really heals or damage dealing abilities. If there are shots in your basic rotation (or whatever support classes have instead of shots) then that's gonna be a mess to measure.

    2. That is what I was worried about. A while back I remember playing around and not noticing pet multistrikes. Perhaps it was a bug at the time. I just worry about the wording and am always trying to think about how I will manged things before I have to so I am not stuck when the time comes having no idea. At least I do not need to worry about my main.

      I know what you mean by the extra rez and what not but I think if that was their intended meaning it could have been worded better. Something like gives a chance to damaging or healing abilities blah blah. I am aware of a few of the support classes having some abilities that can not proc multistrike. I really would not even want to mess with that math clusterfuck. Excuse me language. lol

    3. As far as i know abilities that double dip can not multistrike, Combustion, for example, might be one. Let the mage dot multistrike and do 130% dmg and thus in crease the possible combustion dmg. Now let the Combustion itself multistrike too. The 130% dmg will be 169% after that multistrike (130%*130%). So the problem in this case is the multistrike itself practically mulstistrikes too, and that's what's called "double dipping" and is not intended.
      Those numbers and calculation are most likely not correct (i don't even know how combustion really works :D) but it''s a szenario where an abillitiy should not mulstistrike.

  2. Hey Del Irium! Great post.

    Quick question tho, did you take into account the Critical Chance internal DR mechanic? (http://www.wowwiki.com/Critical_strike). Because so far in beta, Crit still have that soft dr built in. That means it wouldn't be that fair to compare MS to Crit, since they have different results per rating acquired.

    1. Hey, you're totally right. I didn't take that into account. As far as I know, there are two DRs people talk about when looking at Crit, one is what I'll call a "natural" DR, which is the simple fact of arithmetic that 1% additional crit at 75% crit only increases your total damage output by about half a percent, while at 0% crit, 1% additional crit increases your total damage by an entire %. Adding in glancing blows, and other damage reductions, even the 1% crit when you don't have any crit, doesn't actually increase your damage by 1%. I didn't include any armor or dodge/parry/block sort of mechanics, and I was only looking at % chance to crit, in PVE raiding, which admittedly will vary a bit depending on if your using a physical damaging ability or elemental. But this should (i haven't actually tried, but just, logically) have the same effect on Crit and MS.

      There's also an "unnatural" crit dr, or crit suppression, that applies to doing battle with a mob (or player) of a different level than you. I definitely didn't even consider that in this post, and really I have no idea if there will be an MS suppression against higher level mobs (like raid bosses). Hmmm...

      Is there another, different DR on crit that I'm forgetting?

    2. Yeah, a guildie called that out when we discussed this article, that's why I've asked you this. Concerning Crit DRs, there's any other that I can remember.

      From what I've read on EU/US forums, Versatility and Multistrike don't have any kind of diminishing return, so that math you did at the start remains totally correct. They might add it or some other form of control if MS damage gets out of control (not likely imo).

    3. I made it into a guild discussion? That's awesome. I'm still a little bit blown away that anyone reads this site, and when it's discussed (even when it's discussed because I'm wrong about something) it's really exciting for me.

      Anyhow, my point was to talk about the value of the stat for any spec/class, per se, especially since I didn't want to get in mechanics that proc on stats. I mostly just wanted to demystify multistrike as a stat. Thanks for pointing that out, though.

    4. Glancing blows only effects your crit when you reach about 79 percent crit. The combat table makes white hits glancing blows before it makes crits glancing blows, meaning you have to push 100 percent of normal hits off the combat table before your crits will start to glancing blow. The crit suppression is simply a 5 percent flat number, which is balanced by the raid buff, so don't need to concern yourself with that either.

  3. How exactly does versatility work for mm hunters or for that matter any class? Also how much does mastery contribute to sniper training and in that case is it worth having over versatility or even haste. I know crit and ms are the top stats for mm hunter but confused for the rest on where they happen to fall.

    1. Versatility is simply 1% increased damage and .5% decreased damage per 130 of the stat. The devs intentionally increased the stat cost (130 for 1% increased damage instead of 110 like crit and MS) because it included the half percent damage reduction, and they didn't want it to be the clearly superior stat in all situations.

      As for Mastery, for MM hunters, we get 4% mastery regardless of how much of the stat we have, and then for every additional 220 of the stat, we get an additional percent of Mastery. It's not as simple to express in a "X stats = Y% increased damage" type statement, because the value will change depending on how much crit you have, and how much up-time you have on your sniper training buff.

      Sniper training and its effect on your damage is spelled out more clearly here: