# Power attack is a trap

### Skills, Feats, Equipment & Spells

Or more exactly, Power Attack is only useful if you don't have a magic weapon, but because the rules assume you get a magic weapon eventually (which I have other problems with), it becomes useless eventually.

The problem isn't that magic weapons exist. It's that the game assumes you eventually get +X attack and +XdY damage from magic after a certain point. If everyone has a special weapon, no one's weapon will feel special. If you actually want magic weapons to feel magical, then shift the extra damage elsewhere and make magic weapons things like finding a sword that can wreath itself in flames to help fight the hydra terrorizing a village. But as it stands, 66% of the damage done by my test fighter is attributable to mechanically expected magical aid.

My test fighter for purposes of this post is level 9, has 19 Str (18 + 1 level), +17 attack (+9 level + 2 proficiency + 2 magic + 4 Str), and deals 3d12+4 damage on a successful hit. My test opponent is a Treant (CR 8, AC 25). The first attack and Power Attack both have a 65% chance of landing and a 15% chance of critting, for a total of 80% of the expected damage. The second attack has a 40% chance of landing and a 5% chance of critting, for a total of 45% of the expected damage.

Math explanation:

Suppose the probability of a hit is p, the probability of a critical is r, and the expected damage on a regular hit is n. Because the greatsword simply doubles damage on a critical, as opposed to deadly weapons adding different dice, the expected damage output is n*(p-r)+2n*r = np-nr+2nr = np+nr = n(p+r). I.e. I can add the probability of the d20 roll being a regular success and of it being a critical to get a multiplier on expected damage.

The damage for both regular attacks is 3d12+4, which is an average of 23.5, while the damage for the Power Attack is 4d12+4, which is an average of 30. 80% of those is 18.8 and 24 damage respectively, so Power Attack gives a boost of +5.2 damage over the first strike. But 45% of 23.5 is 10.575 expected damage from the second strike, which is over twice what Power Attack gives you.

This math also holds true for weaker weapons. For example, swapping out the d12 for a d8 from a longsword results in 21.875 damage without Power Attack or 17.6 damage with. Or even a dagger with d4s will do 14.375 damage without Power Attack, compared to 11.2 damage with.

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Not particularly disagreed here, I think Power Attack needs a buff. Though I think it's relevant that if your example Fighter was 1 level higher Power Attack would be dealing an additional 1d12, 6.5 average, 80% of which is 5.2 added to the DPR. Still falls just short but it's relevant.

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This has come up before. Above about level 3 its not worth it (until that exact level that you get the bump to bonus 3 dice)