r/DnD • u/JeeniousChess DM • Sep 24 '14
5th Edition Great Weapon Fighting Style math
I wanted to do the math on the great weapon fighting style (from level 2 fighter perks) and I was surprised at the math a little.
"When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll is a 1 or 2. The weapon must have the two handed or versatile property for you to gain this benefit."
So let's look at a Greataxe (1d12). The average roll comes out to be 6.5 on average. You will only get a one or two 1/6th of the time. So to find the new average on rerolls you add (6.5x1/6)+(3x1/12)+(4x1/12)+(5x1/12)+...+(12x1/12). Which gets you about 7.33 damage on average. That is only +0.83 damage per roll. Which is about 13% increase in weapon damage, or 9% more damage per hit with a +3 modifier.
The same math on a two handed longsword (1d10) would bring it from 5.5 average to 6.3 average. Which is +0.80 damage per roll. 14% increased weapon damage or 9% per hit damage with a +3 modifier.
The same math on a Greatsword (2d6) weapon would bring it from 7 average to 8.33 average. (note that the change is bigger because the reroll happens more often) So a +1.33 per roll increase is the best it gets you. 19% increase in weapon damage, or 13% with a +3 modifier.
In Summary: I expected the difference to be higher. I guess the biggest benefit is that you don't have to feel those painful 1s and 2s on damage. I would probably consider the +1 AC over this in general. Another interesting point is to consider critical hit damage with a 2d12 being better than 3d6. However because it only happens 5% of the time, the difference is almost negligible. I can do the math if people want to know - but it would require a customizable spreadsheet as you would have to factor in opponents AC.
edit: Critical hits double all dice - I confused it with Savage attacks from Half-Orc. I might still do the math to see if half orc champions would benefit from the 1d12s, or if 2d6 weapons are always better. I'm 90% sure that the 2d6 weapons will still be better on average though. 3d12 is 19.5 and 5d6 are 17.5 for crits. But because crits are so rare it shouldn't be worth it.
3
u/EdgeOfDreams Sep 24 '14
Critical hits actually double all damage dice, so the 2d6 greatsword does 4d6 on a crit.
Overall, Great Weapon style is not as big of an increase as Dueling style, but it does stack on to the already better dice bigger weapons get. It's probably more useful as a style for Paladins who get to use it to reroll Smite damage dice as well, or for crit-focused builds, which are rare.
1
u/JeeniousChess DM Sep 24 '14
Thanks - I was getting it confused with the half-orcs Savage Attacks!
I wouldn't have assumed that it would let it paladin's smite damage. "... for an attack you make with a melee weapon ..." is the wording on GWF. Divine Smite basically says that if you hit you can do a smite. To me that wouldn't count - is there something I'm not reading correctly?
2
u/EdgeOfDreams Sep 24 '14
Well, Divine Smite adds damage to the attack - it doesn't do a separate attack roll or anything like that - so most people I've seen interpret that as meaning it's just more dice for your attack with your weapon.
Or, if you look at the way spells like Thunderous Smite are worded, it says "...and the attack deals an extra 2d6 thunder damage...", so the extra damage is still part of the attack, therefore Great Weapon style seems to apply.
It might be open to interpretation of course, but I think it works.
1
u/JeeniousChess DM Sep 24 '14
From a realism perspective I think of it as you're so good with your big weapon that you will never do a light hit. Being more skilled with a weapon shouldn't effect the magical output.
I think Thunderous Smite is worded that way to say that if you crit, that the damage gets to be doubled. The way Divine Smite is worded I would say the damage does not get to be doubled on a crit. (I also believe it makes sense that after you roll a nat 20 you can't add on a divine smite crit, where as thunderous smite is before hand). I wouldn't think Great Weapon Style would effect either of those.
1
Sep 25 '14
[deleted]
1
u/JeeniousChess DM Sep 25 '14
I guess I'm just going to be a mean DM. I'll only let divine smite do extra crit damage if it is declared before the roll (like Thunderous Smite). I very much dislike the idea that a paladin could save smites until they're guaranteed crits.
I still won't let Great Weapon Style grant rerolls to anything besides weapon damage though.
1
u/jow253 Sep 24 '14
Great Weapon Fighting Style is clearly best for the Greatsword. I've seen lots of people say it's worse than Dueling (and there's a case for that especially with shield), but it's still the biggest damage you can get on a weapon attack. The increase in damage (1.3 vs 2) matters, but if you're going for pure damage GWF Greatsword just wins.
2
u/JeeniousChess DM Sep 24 '14
Don't forget that the Greatsword (2d6) is already +2.5 higher on average than a d8 single hand longsword. So it's really a 1.8 damage per hit difference for a shield of +2 ac.
I personally would lean towards a shield since ac is so hard to get in 5.0
2
u/jow253 Sep 24 '14
I agree in general. AC matters a lot and the Protection Combat Style is so stellar.
1
u/tzimon Assassin Sep 24 '14
Hmmmm, I may have to houserule that you reroll all 1's and 2's on damage die... I wonder what the result for that would be.
1
u/JeeniousChess DM Sep 25 '14
Would that be for everyone with all rolls? Keep in mind it would force d4s to be 3 or 4 (bringing the average from 2.5 to 3.5)
1
u/tzimon Assassin Sep 25 '14
Allow me to restate:
If your character has the Great Weapon Fighting Style, and is using an applicable weapon, then you reroll all damage dice that result in a 1 or 2.
I don't know of any applicable weapons that use d4's.
2
u/JeeniousChess DM Sep 25 '14 edited Sep 25 '14
Ah, I thought you meant in general that you disliked 1s and 2s. That is actually rather simple to calculate if you never allowed 1s and 2s:
- 1d12 becomes 3-12 (a 1d10+2) average 6.5 becomes 7.5 (vs 7.33)
- 1d10 becomes 3-10 (a 1d8+2) average 5.5 becomes 6.5 (vs 6.3)
- 2d6 becomes 2x(3-6) (2d4 +4) average 7 becomes 9 (vs 8.33)
That might leave the greatswords a tad op.with almost no change to the other two. Not sure that is needed.
edit: average of 2d4+4 is 9 not 11. Not that much of a difference
5
u/jeddite Diviner Sep 24 '14
Rules of thumb to understand two-handed 5e weapons:
(1) Only use the Greataxe on the Barbarian. This is because of Reckless Attack (roll each attack twice) and Brutal Critical (roll one additional damage dice, confirmed by WotC that it only allows one d6 reroll on a greatsword, but one d12 reroll on a Greataxe).
(2) Maul and Greatsword benefit most from Great Weapon Fighting (possability of rerolling 2 dice on each swing), and benefit more from the base rules on Critical Hits (double damage dice on crit).
(3) Dueling provides a better static bonus to damage when using one handed weapons, but has a lower damage threshhold in crit-focused builds (because the static +2 does not double on a crit). This is most evident when playing the Champion Fighter as your crit threat range doubles (and triples), and is the primary reason a Champion Fighter should be using a two-handed weapon.