MathHammer

Overview

MathHammer at its most basic refers to the practice of calculating odds of unit A killing unit B. In the abstract, it refers to the application of statistics to judge army composition decisions.

As the name implies it's frequently used in 40k and Warhammer fantasy, but also applies to other RPGs. It can be very useful in determining the value of a unit, especially when factoring in points costs.

D6 mathhammer, the 216 method

Being built around 3 successive rolls of 1d6 (To hit, To Wound, Save), 40k lends itself to a very quick and effective method for getting a % chance of killing a model, without having to resort to spreadsheets. The 216 method (6^3) simply totals up the chances of getting a result you want, then divides them by the total number of results that can occur, which for rolling 3d6 is 216.

This example will use a Chaos Marine attacking a Guardsman in close combat

1. Total the number of roll results that result in a hit - 3+ so 4
2. Total the number of roll results that result in a wound - 3+ so 4
3. Total the number of roll results that result in a FAILED save - 5+ so 4
4. Multiply them together: 4x4 = 16, 16x4 = 64, this is the number of possible dice rolls on 3d6 that result in what you want, i.e. a casualty.
5. divide the number you got from step 4 by 216, in this case 0.29~, which is the % of a kill.

This gives a result of one attack having a slightly worse than a 1 in 3 chance of killing a guardsman in close combat.

For instances where one of the rolls is ignored, such as with a bolt pistol it becomes the 36 method (6^2), since there are 36 possible rolls for 2d6:

1. Total the number of roll results that result in a hit - 3+ so 4
2. Total the number of roll results that result in a wound - 3+ so 4
3. Multiply them together: 4x4 = 16,
4. divide the number from step 4 by 36, in this case .44~

So a marine with a bolt pistol has a slightly worse than 1 in 2 chance of killing a guardsman.

With these odds readily at hand, the decision to charge a guardsman unit with marines suddenly doesn't have any merit whatsoever, and conversely the guardsmen are probably in a better position if they charge the marines.

Why you would want to do this

So why exactly would you want to recreate statistics 101 in your hobby time? Because GW didn't. Running Mathhammer against your army list will show up the truly junk options that were crammed in your codex, and in turn the absolutely insane power breaks that have no bearing on units points cost. It can however be very useful in avoiding trap units, and putting together viable counters if you are struggling with army composition.

Beware!

Mathhammer, like employing the power of the warp, can be a force for good when used with discipline and restraint. But reckless mathhammer is a step on the path to damnation.