Guidance – Rules 101: Concentrating for Fun and Profit

Welcome to Guidance, Private Sanctuary’s source for tips and techniques for the Pathfinder Roleplaying Game, written by Everyman Gamer Alexander Augunas. Today, we’re going to be talking about concentration checks.

Its one of the most important mechanics in the game for keeping spellcasters in check, yet too many players and GMs don’t know how concentration checks work! Today in Guidance, we’re going to be talking a bit about concentration checks; when you need to make them and how, exactly, they function.

About Special Abilities

You might have noticed that almost every class feature in the game has a little (Ex), (Sp), or (Su) next to it. That’s because when you get right down to it, every ability in the game falls into one of four basic categories: extraordinary abilities, spells, spell-like abilities, and supernatural abilities. These distinctions are important when talking about concentration checks, so let’s go over the differences quickly.

  • Extraordinary (Ex): The ability is non-magical in nature, like a barbarian’s rage or a fighter’s weapon training. They’re above and beyond the norm, but no magic required here.
  • Spells: The ability derives from a class’s spells class feature, such as what the wizard or cleric or bard has. They are 100% magical in nature and subject to concentration checks.
  • Spell-Like (Sp): The ability functions in all ways like a spell, but it isn’t tied to a spells class feature. Spell-like abilities count as spells for all purposes unless a specific instance notes that they don’t. For example, a somewhat recent FAQ notes that a spell-like ability’s caster level doesn’t count for the purpose of meeting feat requirements that call for a general caster level.
  • Supernatural (Su): The ability is magical, but it does not function like a spell or is not tied to a spells class feature. Some supernatural abilities do function exactly like spells, but they are exempt from a number of rules because supernatural abilities are not spell-like.

In a nut shell, something needs to say that it is spell-like in order to count as a spell, and if something is spell-like it counts as a spell for all purposes unless a specific rule states otherwise. Lets move on.

What’s a Concentration Check?

A concentration check is a d20 roll that’s made whenever outstanding circumstances threaten to disrupt the concentration normally needed to cast a spell. A concentration check is equal to 1d20 + the spellcaster’s caster level + the spellcaster’s ability modifier. Your caster level is always equal to the level of the class that granted the ability (or your character level or Hit Dice, if granted by a feat or a racial trait) while each spell or spell-like ability requires a different mental ability score; for example, wizards use Intelligence, clerics use Wisdom, and most spell-like abilities use Charisma. Now, rewind for a minute and note an important line in this explanation: cast a spell. Concentration checks only apply to spells and spell-like abilities, because concentration checks do not specifically note that spell-like abilities are exempt from the concentration. This means that any ability labeled as extraordinary or supernatural does not follow the concentration rules.

A number of conditions can force a caster to make a concentration check. The most common is being injured while casting, but a complete list is included below:

  • Casting Defensively
  • Injured While Casting
  • Continuous Damage While Casting
  • Affected by a Non-Damaging Spell While Casting
  • Grappled or Pinned While Casting
  • Vigorous Motion While Casting
  • Violent Motion While Casting
  • Extremely Violent Motion While Casting
  • Wind With Hail and Debris While Casting
  • Weather Caused by a Spell
  • Entangled While Casting

So remember, these things ONLY matter when you cast a spell used by your spells class feature or when you cast a spell-like ability; supernatural abilities and extraordinary abilities do not matter. Now, let’s talk about each of these things by category. One other important thing to remember about concentration checks is that if you fail, you lose the spell. That means the prepared spell leaves your mind, the spell slot is expended, gone.

Injured While Casting

Whenever you take damage while casting a spell, you have to make a concentration check or lose the spell. The DC changes based upon whether you took a direct instance of damage, such as a readied action made to hit you if you cast a spell going off, or if the damage was “continuous damage” that resulted from an ongoing condition of effect. The most common type of “direct instance” of damage would be the damage caused by a character that readying an action to attack you with a weapon or damage-dealing spell if you cast a spell. Ongoing effects such as the effects of an acid arrow spell or being set on fire also force you to make a concentration check, but only half of the damage is treated as happening when you cast the spell or spell-like ability, so if you take 12 damage from an acid arrow, only 6 of that is used to determine your concentration check DC. This is the second most common type of concentration check, with the most common being the “cast defensively” action.

When you cast a spell, you provoke an attack of opportunity. Casting defensively allows you to cast a spell without provoking an attack of opportunity, but doing so interrupts the concentration required to cast the spell and as a result, requires a concentration check. If you fail a check to cast defensively, you lose the spell, just like normal. Regardless of success or failure, however, you don’t provoke an attack of opportunity when you cast defensively, and generally speaking the DC is almost always higher when you’re damaged while casting compared to when you cast defensively, so casting defensively is a common spellcasting tactic.

Affected by a Non-Damaging Spells

Spells like enlarge person or slow or even ray of enfeeblement break a caster’s concentration if they manage to affect her while she’s casting, so you have to make a concentration check in order to cast when this happens. The DC for a non-damaging spell is fairly low unless you’re affected by a spell with a seriously high save DC, and you’re forced to make the check even if you succeed on your saving throw against the spell and negate its effects. It’s a nasty bit of aftershock that you can leave a caster with if you’re lucky.

In addition, spells that cause weather effects usually include their own concentration check DCs when they’re impeding enough to warrant such a check.

Entangled, Grappled, or Pinned

We’ve talked a bit about this in the last two Guidance articles; the concentration check DC is REALLY hard to beat, especially if you’re grappled by something with a decent CMB (like 99% of grapple-focused monsters). Chances are you’ll lose a spell if you cast it while you’re grappled.

Similar to when you’re grappled or pinned, you’re all tied up when you’re entangled, so you have to make a concentration check in order to cast a spell. The DC is relatively easy at higher levels because it doesn’t scale nearly as well as the DC for being grappled or pinned, but a simple entangle spell can cause a headache for low-level casters.

Motion While Casting

Any type of motion while you’re casting, such as riding a galloping horse, taking a rough wagon ride, or standing on a boat in a storm, all require that you make a concentration check or lose any spell that you try and cast. The DC effectively increases by 5 for every “motion step” that you climb. The DCs aren’t impossible, but it can be an inconvenience since you can’t do much to control the type of motion that you’re experiencing in most cases. (Unless you’re riding a mount and simply want to command it to stop moving.)

Weather While Casting

Particularly rough weather, like wind with rain, sleet, hail, or similar debris also requires a concentration check because its difficult to think in such dangerous conditions.

Enhancing Concentration

Concentration checks are somewhat difficult to improve aside from gaining levels or improving your ability score modifier. Here are a few of the other, more resource-intensive ways to improve your concentration bonus.

  • Combat Casting: The best one by far, Combat Casting gives you a +4 bonus on concentration checks when you’re casting defensively or grappled/pinned. Nifty!
  • Uncanny Concentration: From Ultimate Magic, this feat gives you an extra +2 bonus on your concentration checks AND makes it so you no longer need to make concentration checks when affected by motion or weather. Very, very useful if your GM is into those kinds of encounters. Better still, its only prerequisite is Combat Casting, which you probably wanted anyway.
  • Meditative Concentration: From Faiths and Philosophies, this feat is only for the desperate. It has heavy feat prerequisites and requirements, and while it gives you a +4 bonus on concentration checks, it has a limited window of opportunity. I don’t recommend it, but it exists.
  • Spellguard Bracers: This magic item from Ultimate Equipment is AWESOME. For one, you don’t often see wrist slot items that are worth heavy, especially if you’re able to wear armor. Second, they provided a +2 bonus on concentration checks to cast defensively (arguably the most important kind of concentration check), and they let you roll a concentration check to cast defensively twice and take the better result three times per day. Finally, they only cost 5,000 gp. These are really, really, REALLY good. Especially if you’re someone who doesn’t otherwise need the bracers slot.
  • Desperate Focus: From Cheliax, Empire of Devils, this trait is totally worth picking up if you need an easy source of concentration bonus; it provides a +2 trait bonus on concentration checks, a perfectly balanced investment! There are a couple other traits with a similar bonus, such as the Unhappy Child trait or the Spellpiercer trait. Pick the one that works best for you.
  • Arcane Temper: This is for you casters who hate giving up reactionary. +1 trait bonus to concentration checks, +1 to initiative checks. You’re welcome.
  • Desperate Resolve: This trait only gives you a +1 bonus on concentration checks, but you get a massive +4 while under a huge number of violent conditions, namely while grappled or pinned. If your GM loves to throw monks at you, this plus Combat Casting is a massive +8 to your concentration check against those pesky grapplers. Totally worth it.
  • Stable Gallop: This feat is awesome. It reduces the penalty for firing ranged attacks while mounted AND allows your mount to give you a +4 bonus to concentration checks against the motion caused by its running. Very good if you’re mounted often and that mount can take the feat.
  • Warrior Priest: This feat is oracle/cleric/character with domains only, but it nets you +1 initiative and +2 on concentration checks to cast defensively. Not a perfectly balanced trade, but its not bad if you really find yourself needing more concentration check bonuses after Combat Casting but don’t want the weather and motion benefits of Uncanny Concentration.

And that, my wonderful readers, is all for today. In the future, perhaps we’ll sit down and talk anti-casting tactics to make your foes really regret not investing in these feats, traits, and magic items, but for now we’re through. What do you think? How often do concentration checks come up in your game? How do your players and/or NPCs typically fair when making concentration checks? Leave your answers and questions below, and I’ll see you back here on Friday for a special, spooky sort of treat! Take care.

Alexander “Alex” Augunas has been playing roleplaying games since 2007, which isn’t nearly as long as 90% of his colleagues. Alexander is an active freelancer for the Pathfinder Roleplaying Game and is best known as the author of the Pact Magic Unbound series by Radiance House. Alex is the owner of Everyman Gaming, LLC and is often stylized as the Everyman Gamer in honor of Guidance’s original home. Alex also cohosts the Private Sanctuary Podcast, along with fellow blogger Anthony Li, and you can follow their exploits on Facebook in the 3.5 Private Sanctuary Group, or on Alex’s Twitter, @AlJAug.

Alex Augunas

Alexander Augunas lives outside of Philadelphia, USA where he tries to make a living as an educator. When he's not shaping the future leaders of tomorrow, Alex is a freelance writer for esteemed Pathfinder Roleplaying Game publishers such as Paizo, Inc, Radiance House, Raging Swan Press, and more, and also acts as a co-host and blogger on the Know Direction Network, where he has earned the nickname, "The Everyman Gamer." Recently, Alex has forayed into the realm of self-publishing through his company, Everyman Gaming, LLC.


  1. BardWannabe

    Another feat to consider is Grappled Caster from the Melee Tactics Toolbox, which gives another +4 to concentration checks when gappled that stacks with Combat Casting.

    Another useful article. Thanks, Alex.

  2. Meien

    Also the Tunic of Careful Casting from Ultimate Equipment. It gives +2 to all concentration checks for 5000gp.