How to Improvise Damage for DnD 5e

Let’s say one of your players gets thrown into a fire pit. How much damage do they take? If a character falls in lava and doesn’t die right away, how much damage do they take? Your group’s paladin, who is standing in full plate in a field, is struck by lightning while holding their sword aloft. How much damage do they take? These are questions that you may have to wrestle with as a dungeon master.

Thankfully you’re not expected to know a set value for each of these random examples. Instead, you’ll need to know how to properly improvise damage. Let’s take a look at how to come up with level appropriate damage on the fly for your 5e game.

What is Improvised Damage?

Improvised damage is a way to figure out how much damage a nonstandard weapon or attack might do. This can be used for anything that deals damage but wouldn’t have a set amount applied to it in the rules or books. Usually this includes things like extreme conditions, lava damage, acid pools, fire pits, etc. However, this can also apply to falling rocks, poisonous bug bites, dungeon traps, or anything else just as easily.

This kind of damage, while covering a wide range of cases, does not apply to all non-weapon or non-spell damage. Things like falling damage have a set table you can pull from in the Player’s Handbook (page 183).

Other types of damage may have rules, such as poisons or magical effects, even if they are not listed directly with what they occur on. For example a trap that casts a spell would be assumed to default to the spell’s damage rather than take on improvised damage for being a trap.

The real trick is learning when to apply improvised damage and learning how to do it quickly.

When to Use Improvised Damage

There are no hard and fast rules on how to improvise damage in your game. Improvised damage should be applied when you don’t know what the actual damage would be and are not sure if the damage exists in any set rule.

This should not be relied on just because you’re forgetful, but instead used to keep the game moving. Nothing halts game flow like stopping to look up damage in a splat book that isn’t well-indexed in the first place.

For the sake of argument, knowing how to use improvised damage correctly could hypothetically give you everything you need for all the damage in a game. You could completely improvise an entire campaign, start to finish, and rely on nothing but improvised damage. You shouldn’t do this, but if used correctly your players wouldn’t know the difference between this and specific damage rules.

Improvised damage is best used for a cases such as the following:

  • being hit by falling objects
  • Suffering sudden elemental damage like being too hot or too cold
  • encountering a mechanical damage source like a thresher or winch
  • other non-weapon, non-spell damage sources like a boiler exploding or a magical gem discharging

These are all just examples of when it can be best applied to a situation, but really any time you would have damage where a specific rule is unlikely to exist, improvised damage is the way to go.

How to Use Improvised Damage for 5e

When applied, improvised damage ranges from 1d10 to 24d10. This is important to note because all improvised damage uses d10s. This allows for a fairly wide range of possibilities, but for your use cases you only ever need a d10 to figure it out.

The improvised damage table in the Dungeon Master’s Guide (page 249) lists out examples for when to apply improvised damage and what the scales of damage should be. They are stepped in 1d10, 2d10, 4d10, 10d10, 18d10, and 24d10 levels. What’s even more important than these levels is knowing how dangerous each set is likely to be to different leveled adventures.

This idea is explored more in the second table on the same page and groups damage by character level into setback, dangerous, and deadly categories. While this isn’t perfect, it offers a good yardstick by which to measure the risk involved with each damage type. The levels are grouped 1st – 4th, 5th – 10th, 11th – 16th, and 17th – 20th. Let’s take a look at the lowest level row and discuss how this works more conceptually.

For 1st – 4th level a setback is considered 1d10 damage, dangerous damage is 2d10, and deadly damage is 4d10. In general this works well, but because of the high variability on a d10, a first level wizard is in moral danger on a high roll for even a setback. That same wizard at 4th level is likely to see 1d10 damage more accurately as a setback, where a a 4th level barbarian or fighter wouldn’t bat an eye at it.

The reason these variability and level grouping matter is because as the dungeon master you need to know if applying improvised damage seems reasonable. This is where your judgement comes in.

As a general rule we recommend never killing your players with improvised damage that should be a setback or dangerous. No one likes getting killed by an arbitrary event like tripping on some stairs. It feels very unheroic and does not make for great DnD memories. Depending on the group, we might even suggest fudging your damage rolls to just barely let them escape death.

On the flip side, if you are using the deadly damage column from this table at all, you should definitely not be pulling your punches. If your player characters do something that deserves deadly damage improvisation, by all means slay them. We still advocate for players dying as a consequence of their own actions though, so try not to kill your players without them having a chance to escape damage that is highly random anyway.

Applying Improvised Damage

Improvised damage should be applied quickly to keep the game moving. To do this you need to quickly assess the situation and determine the level of damage you are applying. Rather than remembering a bunch of use cases, you should think about how dangerous the situation is for the player character in question and quickly pick from the table. 

If you want to be safe about your choice, lean more towards setback than anything else. When something is deadly, it’s often quite obvious and you’ll know when to use more dice. Dangerous is your middle ground, but we find that you’ll use this damage range the least since improvised damage tends to skew one way or the other in many cases.

When you’re using improvised damage we recommend applying it behind a DM screen. While DM screens have a lot of advantages, you don’t want your players to think your rulings are random or arbitrary. You’re working within a framework of damage, but keeping your rolls hidden will give you a lot more control over a situation that defies conventional rules.

The main thing you’re trying to achieve with improvised damage is a smooth game with uninterrupted flow. So when you use improvised damage, don’t hesitate.

In the case that you know a rule for damage exists, you can of course look it up. But consider using improvised damage if it’s going to be hard to pull up at a moment’s notice. You’re not announcing that you’re improvising damage to your players, so if you do it correctly no one will know you’ve done anything at all.

Optional Considerations

Sometimes you need to improvise damage but you need it to be more precise. Improvised damage is a d10 by base because it is a wide range and is expected to allow players to miraculously avoid massive damage or be obliterated by the high end of the same scale.

However, when you need to reign things in you can use the same table and drop your dice type to a d8 or a d6. This only lowers the top range, so 1-10 becomes 1-8 and that might be perfect for your needs. 4d10 can be 4-40 damage and 4d8 is 4-32. But even that small decrease could make a big difference when you know where your players fall in terms of lethal damage.

This modification should not get anymore complicated. It’s simply a way to reduce randomness as needed and saves you from having to fudge numbers later because you left too much up to fate.

Improvising is a DM’s Duty

As a dungeon master you’ll find yourself improvising a lot, so getting used to improvising damage is something you should definitely pursue. Knowing what improvised damage is and when to apply it is the first thing you’ll need to get used to. But using the right amount of improvised damage is where the real finesse comes in.

As long as you’re careful with your applications of it and ensure you’re putting your players’ characters into the appropriate damage categories for their level, you’ll be improvising damage like a pro in no time. We hope this helps you understand improvised damage a bit more and gives you a pathway to using it in your game.

Happy DMing!

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