How Much Accuracy is Enough

I'm addicted to accuracy and I assume I'm overslotting for it. I'm unhappy with anything less than a real-number accuracy 1.5 and not really happy until I'm at 1.7. I almost always slot 2 accuracy IO's in every power with a base of 1.0 which means I end up with 1.85+ by level 47. I almost always have a 95% chance to hit just about anything.

The problem is that I have to avoid some sets (or use it with much trepidation) that don't provide what I deem to be sufficient accuracy - Touch of Fear is definitely one. Even Mako's Bite only provides 66%.

So my question is... In general At what point is the accuracy number good enough to give a final hit chance of 95% most of the time. Versus, just for example, +2 bosses or EB's? The typical TF AV?

Also, according to what I'm reading in the wiki, the accuracy IO set bonuses seem to add directly, like the defense set bonuses do. So if a set says +3% then that Mako Bite 1.66 becomes 1.69 (assuming a base accuracy of 1.0)... right? If so that'll make me feel better about slotting those sets if I can make up for it someplace else.

I'm the same, GA. I'll happily stack accuracy bonuses until I'm over 200% to hit an even-con minion. I consider the +66% of two Acc SOs to be a firm target for every power that takes takes accuracy. And I'm often tweaked for it, by people that see my builds. They usually want to see me building for +Defense, instead.

I'm curious, too, about how much is 'enough' for capped values vs... well, even vs. AVs, GMs, and +4 EBs.

Be Well!
Fireheart

The default hit chance of an attack against an even-level enemy is 75%. To cap this, you only need about a 27% accuracy bonus.

~Against +1 enemies, it goes down to 65%, meaning you need a 47% accuracy bonus.
~Against +2s, base hit is 56%, meaning you need a 70% bonus
~Against +3s, base hit is 48%, meaning you need a 98% bonus
~And finally, against +4s (the highest you're really able to meet in normal play), base hit is 39%, meaning you need a whopping 144% accuracy bonus to be capped.

Note that to-hit buffs (or enemy defense) modifies the base chance, so, especially in the case of major level discrepancies, To-Hit is vastly more important. A 10% to hit buff is basically equivalent to 1 level's worth of discrepancy. Likewise, fighting an enemy with 20% defense means you would treat them as if they were two levels higher than you for determining how much accuracy you need to hit.

Enemy rank does not generally have an effect on hit chances, with the caveat that higher ranked enemies are more likely to have higher defense bonuses.

Accuracy is theoretically useful until you reach +1800% (At which point you have a 95% chance to hit something no matter how high its defense is).

You can't have that much accuracy, however, and ToHit is generally more useful (unless your target has more than +45% defense, in which case ToHit has no effect against the "extra defense" of your target).

Those are the most extreme cases, however, and they don't account for PvP Elusivity.

If you want a 95% chance to hit +4s without any built in defense or ToHit debuffs, you will be looking for around 143.5% accuracy (not accounting for ToHit buffs and Defense Debuffs).

Paragon Wiki info on attack mechanics is here.

People in this game seem to have some phobia of missing that supersedes facts and reason.

"Enough" accuracy is a number such that you have a 95% final chance of hitting a mob. What it takes to get to 95% varies by mob level, mob defenses and their ability to debuff your to-hit.

Final to-hit is (min(.95, (1+acc mods) * (min(.95, BaseToHit + ToHit buffs - ToHit debuffs)))). Please don't bother to point out that I didn't include the .05 min chance to hit, we're talking about maximizing here.

Here are BaseToHit for levels conning above you

0 - .75
1 - .65
2 - .56
3 - .48
4 - .39

Assuming no to-hit buffs or debuffs, you'd need Accuracy of

0 0.266666667
1 0.461538462
2 0.696428571
3 0.979166667
4 1.435897436

Kismet, Tactics, Focused Accuracy all have a significant impact and will lower the necessary accuracy.

I'm not crunching any more numbers, but the means to compute "enough" given other to-hit buffs or global accuracy are provided.

I do have a phobia of missing and said as much in the OP. Every miss is wasted endurance and lost time during which my defenses could fail me.

I think I'm getting what the Wiki is saying now. My calculations come up with what you guys are posting. Those would sure be handy tables to add to the page.

So here's what I get using the Wiki formulas and my most unfavorite set, Touch of Death (not Fear, sorry) vs a +2 critter:
HitChance = AccMods * (BaseHitChance + ToHit)
HitChance = (1.0 * (1.0 + .434 + 0)) * (.56 + 0)
HitChance = 1.434 * .56
HitChance = .80304 or around 80%

Yuck.

You are right about Focused Accuracy. The change is nothing short of dramatic. I happened to look at it last night in the power monitor and it seems to add 20% Accuracy AND 20% To-Hit. That accuracy is added to my personal base accuracy so I assume (correct me if I'm wrong) that means the base accuracy of my power also jumps from 1.0 to 1.2.

If so the calculation changes as...
HitChance = (1.2 * (1.0 + .434 + 0)) * (.56 + .2)
HitChance = 1.7208 * .76
HitChance = 1.3078 or 130% capped at 95%

If so that means my characters with FA could handle up to +4's using what I would consider sub-par accuracy modifiers and still be capped at 95% to-hit. Heck, they could have NO accuracy enhancement and still be above 90%.

Am I doing this math wrong because... wow!

Well, on my most of my characters, missing occasionally is okay. I will typically have around 35-45% accuracy in each attack plus maybe 20% global accuracy.

On my main character, Ironblade, that's not enough. Firstly, I play him more than any other toon. Second, he mostly plays high-end content. Finally, his primary is broadsword which has long recharge and high END cost. Therefore, he has:
- approx 60% accuracy in every attack
- 57% global accuracy bonuses
- Kisment +to hit unique
- Tactics
- Focused Accuracy

I don't normally run FA. I save that for Paragon Protectors with Moment of Glory or Rikti Drones that have been bubbled by a Rikti Guardian. Then I turn on FA and beat them like a rented mule.

My memory is terrible so that explains that.

I also put the 20% focused accuracy bonus as part of the base accuracy instead of as an enhancement like you did and that makes a difference too.

I think I've got it now. Thanks.