The damage for the spell delayed blast fireball is listed as:

The spell’s base damage is 12d6. If at the end of your turn the bead has not yet detonated, the damage increases by 1d6.

The spell's duration is "Concentration, up to 1 minute".

Does this damage increase repeat on each of your turns throughout the spell's duration?
Or does it only apply to the turn when you cast the spell?

I tried to draw comparison to the 3.5e version of the spell, but according to the d20 SRD, there is no damage bonus for delaying the blast in D&D 3.5e; the spell is simply more powerful than fireball.


2 Answers 2


Yes, every turn you delay the explosion you increase the damage by +1d6, up to the max of 10 turns, 12d6+10d6 = 22d6.

  • \$\begingroup\$ Is the max duration due to the fact that a round is 6 seconds (1 min concentration) or is that RAW for the spell? \$\endgroup\$ Commented Jul 15, 2015 at 21:28
  • 1
    \$\begingroup\$ 1 round = 6 seconds, 60 seconds in 1 min, so 60/6 = 10 rounds. So, Yes, due to both 1 round = 6 seconds and RAW 1 min duration. \$\endgroup\$
    – GreySage
    Commented Jul 15, 2015 at 21:31
  • 2
    \$\begingroup\$ And if you cast the spell with a level 9 slot, the damage can go up to 24d6! \$\endgroup\$ Commented Mar 19, 2016 at 8:15

It gets better..

Yes.. every single turn you delay the Fireball it goes up 1d6 damage...

Which means if you use the Extended Spell metamagic, the damage can go up to 32d6.

And if you use the Elemental Adept feat, you ignore resistance and reroll 1's.

Aaaand if you have Draconic Ancestry (Gold/Red dragon) you add your Charisma bonus to the roll as well..

So a +5 Charisma means.. 69 -197 damage to everyone in range.

Well.. assuming the room isnt full of gunpowder and oil.


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