How does spell casting work with regards to concentration and multiple spells?

The other players in my group are arguing that duration-based spells require concentration and the casting of any other duration-based spell would cause the first to disappear.

For example, they say that if I cast Produce Flame, that is the only spell I can cast until I have used the spell entirely, or if I choose to cast another spell such as Flaming Sphere then Produce Flame's effects end as I'm no longer concentrating on it, even though the duration specified has not ended.

I find this interpretation extremely limiting on spellcasting, especially as a druid, as it means I can't ever use multiple spells that have durations of more than one turn, like Summon Nature's Ally, Entangle, Flaming Sphere and others.

The way I understand it is that only spells specifying concentration in its use, such as Summon Swarm, require the user to actively concentrate on the spell, and that only another of these concentration-based spells would cause the first to cease and that the casting and use of multiple non-concentration spells was fine.

  • \$\begingroup\$ I feel like you(r friends) basically described how I feel most spells are in 5e:P If they're 5e players maybe that's where they got that feeling from. \$\endgroup\$
    – joedragons
    Jul 5 '16 at 15:40

For reference, here are the rules for duration.

They're arguing that non instant spells require concentration and the casting of any other non instant spell would cause the first to disappear.

I can't find anything in the RAW to support this. Let's call it a house rule for the sake of discussion.

(I can't find anything that explicitly refutes it either, but that's for the same reason that I can't find anything to refute the idea that every time a character casts a spell their player has to light a big dribbly candle and use it to melt a D4)

Watching how that house rule interacts with obvious things shows it to be ridiculous.

Mage Armor has a duration of 1 hour/level. It is traditional for a wizard to cast it on themselves before going into danger. There isn't a whole lot of point in doing that if they won't be able to do anything other than shoot things with their crossbow (or if the rules for maintaining a spell that requires concentration are used, not even that since they would only get move and free actions as the standard action would be eaten by maintaining Mage Armor).

Gentle Repose has a duration of One day/level. When a Wizard gets access to the spell at level 5, that would allow them to maintain it for 5 days … providing they could concentrate, which would involve not going to sleep, for that long.

Then we get Permanent Image with a duration of Permanent. It's rather pointless if it goes away as soon as you stop spending a standard action every round to keep it.

Then we have spells with a duration of concentration (or concentration + 1 round, etc). It makes no sense to define a spell with a duration of concentration if all spells require concentration.

Your understanding is correct. The other players are wrong. If a spell doesn't have a duration that mentions concentration, then it is a Fire & Forget spell.

  • \$\begingroup\$ Note that some spells (such as Flaming Sphere) have a fixed duration but require an action from the player to "do" something. This might be what has triggered the idea that it required concentration. \$\endgroup\$ Jul 4 '16 at 10:11

I believe your friends might be confusing spells with the concentrate duration on them.


The spell lasts as long as you concentrate on it. Concentrating to maintain a spell is a standard action that does not provoke attacks of opportunity. Anything that could break your concentration when casting a spell can also break your concentration while you’re maintaining one, causing the spell to end.

You can’t cast a spell while concentrating on another one. Sometimes a spell lasts for a short time after you cease concentrating.

As an example. You cast a spell with the duration:

Concentrate + 1d6 + 1

What this means is you can keep the spell going as long as you concentrate but when you stop concentrating on it the spell continues for 1d6+1 rounds.


If you are playing 3.5 D&D, according to the PHB, all spells, unless specifically stated otherwise, require concentration to cast:


You must concentrate to cast a spell. If you can’t concentrate you can’t cast a spell. If you start casting a spell but something interferes with your concentration you must make a Concentration check or lose the spell. The check’s DC depends on what is threatening your concentration (see the Concentration skill). If you fail, the spell fizzles with no effect. If you prepare spells, it is lost from preparation. If you cast at will, it counts against your daily limit of spells even though you did not cast it successfully.

Further, any spells that require continued concentration may require subsequent concentration checks to maintain that spell for another round. Lastly, according to traditional 3.5 rules, you cannot cast another spell while you are currently concentrating for another duration spell.

Concentrating to Maintain a Spell

Some spells require continued concentration to keep them going. Concentrating to maintain a spell is a standard action that doesn’t provoke an attack of opportunity. Anything that could break your concentration when casting a spell can keep you from concentrating to maintain a spell. If your concentration breaks, the spell ends. You can’t cast a spell while concentrating on another one. Sometimes a spell lasts for a short time after you cease concentrating."

I use a house rule that allows up to three continuous concentrated spells, with a caveat of increased concentration DC.

  • 2
    \$\begingroup\$ That does not appear to indicate that it requires a concentration check every time you cast a spell; rather, you must make a concentration check if something interferes with your concentration. \$\endgroup\$ May 30 '19 at 1:27
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    – V2Blast
    May 30 '19 at 1:39
  • \$\begingroup\$ No, they do not neccessarily require a skill check, but they all require concentration. I misquoted. There are many situations and conditions that ellicit concentration checks. And house rules for distractions as well. But regardless, you can't cast stacked continuous spells that require concentration. If you cast to concentrate on another spell, you lose the concentration on the spell you were maintaining. \$\endgroup\$
    – Ben B
    May 30 '19 at 1:56

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