Random Encounter Generator
Build encounter tables by terrain and roll weighted random encounters.
Overview
The Random Encounter Generator builds and rolls weighted encounter tables organised by terrain. Pick a terrain (forest, mountain, desert, urban, dungeon, coastal, plains, swamp), and the tool either rolls a random encounter from its built-in table or lets you supply your own custom entries with weights. The result is a one-line encounter seed you can drop into a tabletop session.
Encounter tables are a foundational tool of tabletop game-mastering. They keep the world feeling alive between scripted plot beats, provide easy tension when players linger somewhere, and let the GM react to player decisions without prepping every cubic mile of the map. The built-in tables borrow from old-school D&D random encounter conventions.
How it works
Each terrain has a weighted table of encounter strings — most entries describe a hostile group, some describe non-combat events (travellers, weather shifts, environmental hazards), and a few are flavour beats with no immediate consequence. Weights bias the distribution so that common encounters like wolves in a forest appear more often than rarer events like a wandering dragon.
The roll uses cumulative-weight sampling: weights are summed into a prefix array and a uniform random sample of the total selects the entry whose prefix interval contains the sample. You can override the built-in weights or supply a completely custom table to match your campaign setting, and the output is a single-line string suitable for note-taking.
Examples
- Terrain "forest" roll: "A pack of six wolves stalking from upwind. Survival DC 12 to spot them before they pounce."
- Terrain "mountain" roll: "A goblin scouting party of four, mounted on wolves and carrying a captured villager."
- Terrain "urban" roll: "A pickpocket bumps into the party — sleight-of-hand check vs perception."
- Terrain "swamp" roll: "Sudden fog reduces visibility to 20 feet. Lost-pace checks for the next hour."
FAQ
Are the tables balanced for any specific edition?
The defaults skew toward fifth edition D&D's CR conventions but the strings are system-agnostic.
Can I add custom entries?
Yes — supply a list of strings with weights and the generator uses your list instead of the built-in one.
How frequently should I roll encounters?
Old-school dungeons roll every ten minutes of in-fiction time. Modern tables usually roll only when the players signal a slow stretch.
Does the same entry roll twice in a row?
Possible — each roll is independent. Many GMs re-roll if they get an immediate repeat for narrative variety.
Are the entries combat-only?
No. The tables mix combat, exploration, and social events to keep travel scenes varied.