Encounters are the bread and butter of D&D. They’re the scenery that stops players from getting bored on their way to their main destination; they’re the stage for important plot points; and they’re vital for characters to grow stronger. The Dungeon Master acts as the game’s manual D&D encounter builder, but they don’t have to do this work alone.
You see, building DnD encounters is absolutely full of maths. You’ll need to consider character levels, XP thresholds, multiple monster multipliers, challenge rating, saving throws – the list of things that affect your encounter ‘budget’ goes on. That’s right, you’re budgeting in tabletop RPGs – it starts to sound less like a game, and more like a tax statement. We’re not even taking into account the different ways of building encounters in the Dungeon Master’s Guide versus Xanathar’s Guide to Everything.
If you’re a DM who likes a slightly less maths-y time, you might consider using a D&D encounter builder 5e. These do the hard work for you, and they can even suggest DnD monsters and treasure that suit your needs.
These are the best D&D encounter builders:
D&DBeyond
D&D’s official digital platform has its very own encounter calculator, and D&DBeyond’s encounter builder is one of the best for many reasons. Firstly, the number of filters you can apply to narrow down your search is huge. You start with a huge list of monsters to choose from, but you can narrow down your ideas based on anything from the creatures’ alignments, immunities, or even the D&D books they’re found in. Given how much nuance goes into crafting a perfectly balanced encounter, this will definitely come in handy.
D&DBeyond’s encounter builder is also pretty easy to understand visually. After you’ve entered the number of characters and what level they are, you’ll get a pre-calculated XP budget showing what you need to hit to make an encounter easy, medium, difficult, or deadly.
As you add creatures to your encounter, a coloured line appears in the summary to help you hit your desired difficulty level. Want to know how many apes it’ll take to wipe out your level-four party? We don’t know why you need this information, but D&DBeyond can tell you.
Given that D&DBeyond hosts pretty much every feature you’d need to run digital DnD games, you’ve also got the option to save your encounter for later – no need to hastily scribble all this information down in a messy notepad.
Donjon generator
Donjon 5e random generator is another encounter calculator site that offers a huge range of options.
It doesn’t even stop at D&D 5e – you can find various generators for Pathfinder, the Alien RPG, as well as some older editions of D&D. But you came for great D&D 5e encounter builders, and Donjon shall provide.
In terms of filters, this is a relatively simple generator – all you need to fill in is the number of player-characters, their level, what difficulty you’d like the encounter to be, and what environment it will take place in.
Based on this, Donjon suggests ten different encounters to choose from, each with different monsters and treasure to loot (something not all other 5e encounter generators provide). Having encounters suggested rather than needing to build your own will come in handy if you’re stuck for random encounter ideas.
RPGBot
RPGBot is a TTRPG resource website that offers information and calculators for different editions of both D&D and Pathfinder. The 5e encounter generator starts with a handy summary of the rules for a D&D encounter, then it splits the calculations down into two steps – party settings and encounter settings.
RPGBot offers a very streamlined generator, but this does mean you still need to do the bulk of the work yourself. You’ll need to choose and input your monsters manually, and you’ll have to figure out how factors like immunities and saving throws might skew difficulty levels.
Basically, you’re going to need a Monster Manual and your party’s character sheets handy.
One thing RPGBot does well, though, is laying out the tables for the ‘fractional method’ of calculating encounters – the alternative method you’ll find in Xanathar’s Guide to Everything. These are quickly generated, and they’re easy to copy or save digitally for later.
AideDD
AideDD’s encounter generator combines the coloured difficulty bar from D&DBeyond with the options for calculating treasure Donjon provides.
Like many of the other generators on this list, it doesn’t account for factors other than character level and XP, but it’s naturally quicker to use because of this. It also has a drop-down list of monsters to choose from to save you from flicking back and forth between sourcebooks for info.