Building a balanced encounter or filling out a campaign world by hand takes real time, and most Dungeon Masters end up leaning on at least one outside tool to speed up the process. This roundup covers the encounter and campaign generators worth knowing about in 2026: what each one actually does, what it costs, and where it falls short.

Why a dedicated generator still beats winging it

A quick mental encounter, "three goblins and a bugbear," often turns out unbalanced in practice, either a curb stomp or a near total party kill, because Challenge Rating math doesn't scale linearly with monster count the way it feels like it should on paper. Even a rough pass through a free calculator catches the most common mistake: stacking too many lower CR monsters and underestimating the action economy advantage a group of enemies has over a single tough one. None of the tools below require a subscription to get this basic check, so there's little reason to skip it even for a throwaway random encounter.

Quick comparison

Tool	Type	Price	Best for
Kobold Plus Fight Club	Encounter balancer	Free	Fast CR based encounter math for D&D 5e
Donjon	Random generator suite	Free	Dungeons, NPCs, loot, and encounters across multiple systems
Chartopia	Random table platform	Free	Community made charts for almost anything, including encounters
Eigengrau's Generator	Town and NPC generator	Free, open source	Instant towns, taverns, and NPCs with ready to read text
D&D Beyond Encounter Builder	Official encounter tool	Free with a D&D Beyond account	Encounters tied directly to your D&D Beyond characters and compendium
Sprixen Encounter Generator and AI Dungeon Master	Free generator plus AI run adventures	Free generator; AI Dungeon Master runs on credits, 6 free at signup	Quick encounter ideas, or a full AI narrated one-shot
Friends & Fables	AI game master, Discord and web	Free tier available	A full AI run D&D 5e campaign, solo or with friends

Kobold Plus Fight Club

The original Kobold Fight Club was a long running staple for balancing D&D 5e encounters by Challenge Rating, but the original site eventually went offline. Kobold Plus Fight Club is an actively maintained rewrite by Fantasy Computerworks that keeps the same core workflow: filter monsters by Challenge Rating, environment, size, and type, drop them into an encounter, and get an automatic difficulty rating using the official Dungeon Master's Guide encounter building math. If you bookmarked the original years ago, this is the tool that replaced it.

Donjon

Donjon is a long running, entirely free collection of random generators covering dungeons, NPCs, loot, magic shops, traps, and encounters across several game systems, including a dedicated d20 encounter generator that pulls monsters by encounter level, climate, and terrain. It has no subscription, no account requirement, and no interface polish to speak of, but the sheer breadth of generators makes it a genuinely useful bookmark for filling in details on the fly.

Chartopia

Chartopia is a platform for building and rolling on random tables, called charts, created and maintained by a small independent team. Anyone can publish a chart, so the library ranges from generic fantasy encounter tables to oddly specific ones like themed loot or NPC quirk generators. It's free to use, and charts can link to other charts so one roll can cascade into a fuller result. The tradeoff is quality control: since anyone can publish, results vary chart to chart in a way the more curated tools don't.

Eigengrau's Generator

Eigengrau's Generator, formally Eigengrau's Essential Establishment Generator, is a free, open source tool that generates a small fantasy town, complete with named buildings, NPCs, and a plot hook, all written as ready to read paragraphs rather than raw stat blocks. It's less about combat encounters specifically and more about the texture between encounters in a session: a tavern to describe, a blacksmith with a name and a quirk, a rumor to plant.

D&D Beyond Encounter Builder

D&D Beyond's own Encounter Builder is free to use with a D&D Beyond account and lets you build an encounter directly against your players' actual character levels, drag monsters in from the compendium, and see a live difficulty calculation. Its biggest advantage is also its limitation: it's tightly integrated with D&D Beyond's own character and monster data, so it works best if your table already lives inside that ecosystem, and less well if you're running a homebrew system or heavily modified monsters from outside sources.

Foundry VTT's own combat and encounter tools

Foundry doesn't ship with a dedicated encounter-balancing calculator the way D&D Beyond does, but its built-in Combat Tracker handles initiative, HP tracking, and status effects once an encounter is already assembled, and several community modules extend that with monster browsers and quick-add tools pulled from installed compendiums. If your table already keeps its bestiary inside Foundry, building the encounter there and using an external calculator like Kobold Plus Fight Club just for the difficulty math is a common combination, rather than expecting one tool to do both jobs.

AI run options: Sprixen, Friends & Fables, and general AI tools

A newer category runs the scene for you rather than only helping you build it. Sprixen's free encounter generator gives you a quick, themed encounter idea in seconds, and its AI Dungeon Master goes further, narrating a full one-shot adventure or an ongoing session turn by turn, including its own generated maps and tokens. It runs on a credit system: a one-shot adventure costs 3 credits, each turn afterward costs 0.2 credits, and every new account starts with 6 free credits.

Friends & Fables takes a similar approach but built specifically around Discord: its AI game master, Franz, runs actual D&D 5e sessions with leveling, HP tracking, and spellcasting, and supports both solo and multiplayer play across the Discord bot and its own web platform. It's a mature product with a large existing community. For a general purpose AI storytelling tool that isn't D&D specific, AI Dungeon remains the best known option, though it's built for open ended text adventures rather than tracking D&D 5e rules and character sheets.

Homebrew content and custom monsters

Every tool on this list handles homebrew differently. Kobold Plus Fight Club and D&D Beyond's Encounter Builder both let you add custom monster stat blocks so a homebrew boss factors into the difficulty math correctly instead of being left out entirely. Donjon and Chartopia are built around fixed content and generic tables rather than your specific homebrew, so they're better suited to inspiration and filler content than to precisely balancing an encounter built around a monster you created yourself. If your table runs mostly official content, this distinction matters less; if you build a lot of custom monsters, prioritize the tools that let you import them directly.

How to choose

If you just need fast, accurate CR math for a homebrew encounter, Kobold Plus Fight Club is the most direct tool for that one job. If you want breadth across dungeons, loot, and NPCs in one place, Donjon covers more ground than any single purpose tool. If your table already lives on D&D Beyond, its own Encounter Builder saves you from re-entering character data anywhere else. And if what you actually want is for something else to run the session, not just help you prep it, an AI Dungeon Master style tool is a genuinely different category from the generators above, worth trying for a solo session or a night when nobody wants to prep.

For more on that last category specifically, including its real strengths and limits, see the honest guide to solo play with an AI Dungeon Master. And once you've got an encounter, you'll likely need monsters and NPCs to populate it: the NPC generator roundup and the monster maker comparison cover those pieces separately.

FAQ

Is Kobold Fight Club still working?

The original Kobold Fight Club site eventually went offline. Kobold Plus Fight Club is the actively maintained successor, built by Fantasy Computerworks with the same core encounter balancing workflow.

Is Donjon free?

Yes. Donjon has been a free collection of RPG generators for many years, with no account or subscription required.

What's the difference between an encounter generator and an AI Dungeon Master?

An encounter generator gives you monsters, terrain, or a scenario idea that you then run yourself. An AI Dungeon Master actually narrates and adjudicates the session in real time, describing scenes and responding to player actions turn by turn.

Does D&D Beyond's Encounter Builder cost extra?

It's free to use with a standard D&D Beyond account. Some newer or experimental D&D Beyond features have launched behind a paid subscription tier first, so it's worth checking current access on D&D Beyond's own site if a specific feature seems locked.

Can I run a full campaign with an AI Dungeon Master instead of a human DM?

Many people do, especially for solo play or when a group can't find a human DM. The tradeoff is that AI tools are generally weaker at precise rules math and long-term plot memory than an experienced human DM, so they suit improvisational, lower stakes play better than a tightly ruled tournament style campaign.

Do any of these tools work for systems other than D&D 5e?

Donjon and Chartopia both cover multiple game systems beyond D&D. Kobold Plus Fight Club and D&D Beyond's Encounter Builder are built specifically around D&D 5e's own math and won't produce accurate difficulty ratings for a different system's rules.

Best D&D Encounter and Campaign Generators in 2026