Converting from 4th to D&D next


I have been playing around with a conversion method for monsters to go from D&D 4th to D&D Next.

Basically, using excel, I assess the %chance of a hit on the monster by a +5 PC. I multiply that %chance to hit by an assumed 10 hits of damage. I then divide that average damage per round by the number of total hitpoints the monster has. This gives me the number of rounds the monster will be expected to last in combat.

After that, using a similar method, I work out how much damage the monster is likely to do per round to a 15AC PC. I multiply that by the number of rounds the monstor is expected to last in combat. The final number is "total damage dished out by the monster before he dies". Lets shorten that to "TD Rating"

Using excel to do this for a range of monsters I found this:
4th Edition: every 1xp of monster is worth about 0.6 TD rating
5th Edition: every 1xp of monster is worth about 0.2 TD rating

(i.e. 4th Monsters are much tougher for the given xp value)

I then went about trying to come up with a conversion from one to the other.

What I found was that if you do the following for the 4th Edition Monster:

5th Edition AC = 4th Edition AC minus (Level/2 Rounded down)
5th Edition to Hit = 4th Edition to Hit minus (level/2 Rounded down)
5th Edition hits = 4th Edition hits/2

If you do this your converted 4th Edition Monsters now becomes every 1xp of monster is worth about 0.18 TD rating (not perfect but its an easier conversion to remember than hits*55%) 

Anyone spot any major flaws with this method?
1) What are you basing your assumptions about monster activity in either edition on? (ie, how long you expect them to live, how often you expect them to attack, etc)

2) How are you accounting for the variances in 4e's scaling that happens between mid-tier (levels 6, 16, and 26--the points at which 4e PCs are strongest relative to monsters +/-3 levels) and end-tier (levels 10 and 20--the points at which 4e PCs are weakest relative to monsters +/-3 levels)?

3) Are you making distinctions between 4e monster type and role? (Brutes hit harder, but Soldiers are more accurate, for example. Likewise, Minion, Standard, Elite and Solo monsters all provide very different expected profiles of activity, longevity, resilience and threat)

4) How are you accounting for the differing rates of attack and defense progression for monsters and PCs in 4e? (Monster defenses increase faster than PC attacks; this is why "match patch" feats like Expertise exist)

5) How are you translating 4e monster attacks that target NADs?

6) How are you adjusting the XP values of monsters to compensate for different level progressions?

7) How are you adjusting monster HP relative to PC damage output? A Next Goblin has 3 HP. A 4e Goblin has 30.

I don't think I have accurate methods on any of those questions but I'm hoping the conversion is "accurate enough".


1) I have worked out damage-per-round for the monster (e.g x2 attacks per round at d6 each is average of 6dmg per round). I match the monster against a token player character of infinite hit points but AC15, +5 to hit, 10 hits damage done per hit. I basically work out how much total damage the monster does to the token player character before the monster dies. The total damage done by the monster under these circumstances is a simplification of how bass-ass the monster is.


2) I don't think I need to account for this....its a monster to monster conversion for a given XP value


3) I have not done this. This may be too much of an over-simplification in my method. It may give some big monsters like huge dragons too many hit points for a D&D next game. Got any suggestion on how to deal with that one?


4) For a given XP value, using the conversion makes the monsters equally dangerous.


Orc Leader in Next. 340xp - Total Damage 64.

Ogre Savage in 4e. 350xp - Total Damage 444 (i.e. roughly same XP but 4e does MUCH more damage)

Ogre Save in 4e after my conversion. 350xp - Total Damage 99.9 (Damage is ball-park equivalent for the same XP....remember the method came from averaging results over several monster types)


5) Looked at simple hack-and-slash monster only


6) No XP adjustment required. You keep the same XP. I am using this method on the 4e scales of war campaign (Dungeon magazine 156) and playing it with D&D Next rules and it seem to reasonably well balanced so far


7) Things do get a little inaccurate on the extremes. I started the PC's on level 2 to compensate and it worked out fine.

I've noticed that most damage convertions get a little to edgy in damage output. Any thougs in how to decrease this? In your calculation for example--like half damage or Damage minus 20... i dunno. thanks in advance for any ideas...


May all your luck be fortunate and your rolls always have advantage!
...If you're playing the defining edition of Dungeons & Dragons.

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