How Heroic Inspiration Works in D&D 2024

Heroic Inspiration lets you reroll any die immediately after rolling it, you must use the new roll, and you can never hold more than one. Heroic Inspiration is the only reroll in SRD 5.2.1 that works on any die. Most tables hand it out and then forget it. Spent well, it turns a miss into a hit about as often as Advantage does.

The rule

If you have Heroic Inspiration, you can expend it to reroll any die immediately after rolling it, and you must use the new roll.

Three things follow from that sentence. You see the roll before you decide. It works on any die: a d20, a damage die, a Hit Die. And the second roll stands, even if it is worse.

You can hold one, never two:

You can never have more than one instance of Heroic Inspiration. If something gives you Heroic Inspiration and you already have it, you can give it to a player character in your group who lacks it.

The glossary says the same thing from the other side: a second one is "lost unless you give it to a player character who lacks it."

Where it comes from

Typically, GMs award it when you do something particularly heroic, in character, or entertaining. It's a reward for making the game more fun for everyone playing.

One rule hands it out on a timer. Every Human has the Resourceful trait:

Resourceful. You gain Heroic Inspiration whenever you finish a Long Rest.

So a Human starts every adventuring day with one reroll. If it is still unspent at the next Long Rest, the new one has nowhere to go but to a friend. Unspent Heroic Inspiration at the end of a day is a reroll thrown away.

Halfling Luck, the smaller cousin

Luck. When you roll a 1 on the d20 of a D20 Test, you can reroll the die, and you must use the new roll.

Luck never runs out, but it only fires on a 1, and only on the d20 of an attack roll, ability check or saving throw. Heroic Inspiration fires on anything, once.

With Advantage or Disadvantage

When you have Advantage or Disadvantage and something in the game lets you reroll or replace the d20, you can reroll or replace only one die, not both. You choose which one.

With Advantage, reroll one die only when both missed. With Disadvantage, reroll the low die when the other one already hits; if both missed, a reroll of one cannot save you, so keep it.

What one reroll is worth

A Fighter with +5 to hit swings at a Goblin Warrior, AC 15. The Fighter needs a 10 on the d20: 55%.

Spent on a miss, one Heroic Inspiration equals Advantage on that attack. Spent with Disadvantage, it cancels it, and a little more.

Spend it on the d20, not the damage

"Any die" tempts players to reroll a bad damage roll. The numbers say no.

Greatsword damage is 2d6, average 7. Rerolling the lower die whenever it shows 3 or less lifts the average to 8.24: a gain of about 1.2 damage. A Fireball's 8d6, rerolling the lowest die when it shows 3 or less, gains about 2.2 on an average of 28.

Now spend the same reroll on that Fighter's missed Greatsword swing: 55% of the time it becomes a hit worth 2d6+3, average 10. That is 5.5 damage, four times the damage reroll.

The rule of thumb: reroll the d20 that decided whether anything happened. Reroll damage only when the d20 already hit and the damage is the last thing standing between an enemy and 0 Hit Points.

The best reroll in the game: a death save

A character at 0 Hit Points rolls a d20 each turn: 10 or higher is a success, 9 or lower a failure, a 1 counts as two failures, a 20 brings the character back with 1 Hit Point. Three successes and the character is Stable; three failures and the character dies. Our death saving throws post has every rule quoted.

Left alone, with no help, here is how it ends:

One Heroic Inspiration cuts the chance of dying from 40.5% to 23%. No other single choice a downed character can make comes close, because a downed character can make no other choice at all.

That gives a Human's daily reroll a clear default: hold it for the death save, and spend it on a key attack or save in the last fight before the Long Rest, so it never goes to waste.

Pass it on

A GM can award Heroic Inspiration to a player who already holds one. That player can hand it to anyone at the table who lacks it. A table that passes rerolls around spends more of them, and spent rerolls are the only kind that change a fight.

This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License.