RPG Generator for Maps: Seeded Battle Maps in Under a Minute
Reviewed by the FreeOnline.fyi team · Updated 2026-09-14
Who actually needs a procedural battle map
The most common game master problem isn't a lack of ideas — it's the gap between "the party fights in a collapsed mine" and having something to put on the table. That gap usually gets filled with one of three things: a scribbled grid on a whiteboard, a stock map that doesn't quite fit, or twenty minutes in an image editor. None of those are what you want at 7 p.m. on a Tuesday.
RPG Generator for Maps exists for exactly that moment. You pick a map type, a grid size, a theme, and a seed, and a live canvas redraws a dungeon, cave, wilderness, or town map as you move the sliders. When it looks right, you download a PNG (or an SVG) and you're done.
The people who get the most out of it tend to be improvisational GMs running one-shots, hex-crawl and West Marches referees who need a lot of maps and don't care about hand-crafting each one, VTT users who just need a background image to import, and teachers or writers using tabletop mechanics to structure a session. If your prep style is "three bullet points and a monster stat block," this fits. If your style is hand-drawing every corridor, it probably won't replace your sketchbook.
What the controls do — and what they deliberately don't
The control set is small on purpose. Map type chooses the generator (dungeon, cave, wilderness, or town) and re-renders the moment you change it. Grid size runs from 20 to 80 tiles per side; above about 60 the tool warns that rendering may take a moment, which is honest — you're asking the browser to draw several thousand tiles. Room or feature density runs 4 to 20 and is clamped per map type, so "20 rooms in a cave" produces something different from "20 rooms in a dungeon."
Theme is the one control that changes nothing structural. Parchment, ink, blueprint, and dark only alter the render colors, so you can flip between them mid-preview and keep the exact same layout. Same goes for the grid overlay toggle: it's a visual layer over the same geometry.
Under the hood it uses well-worn techniques rather than anything exotic — the dungeon generator lays out rooms and corridors with binary space partitioning, while caves lean on cellular-automata-style growth, both long-standing approaches in procedural generation. The important limitation: it draws geometry, not content. There are no door keys, no monster tokens, no room numbers, no treasure. Stocking the map is still your job.
The seed is the feature that changes how you prep
Every map is driven by a text seed. Type in any string, and the same seed plus the same settings will always produce the identical map. That sounds like a small thing until you use it: you can generate a dozen variants by mashing the seed field, keep the one you like, and write the seed down in your session notes.
It also makes maps shareable. Instead of emailing a PNG and hoping your co-GM uses the right one, you can send six characters and tell them to regenerate it. The legend and summary block under the canvas lists the seed, the tile dimensions, the room count, and the theme, which is the piece of information people forget to save when they generate on impulse.
Two edge cases are worth knowing. First, if you leave the seed field empty, the tool substitutes a fresh random seed rather than erroring out — handy, but it means an empty field isn't reproducible. Second, changing density or map type with the same seed generally gives you a *different* map, not a rearranged version of the same one. If you want to preserve a layout, copy the seed and settings together before you touch anything else.
Choosing between dungeon, cave, wilderness, and town
The four map types aren't just cosmetic reskins; they produce meaningfully different tactical spaces. Dungeons give you rectangular rooms connected by corridors — lots of chokepoints, clean line-of-sight questions, easy to describe. Caves come out organic and irregular, which is great for natural caverns but harder to narrate room-by-room because the spaces don't have obvious boundaries.
Wilderness maps read as open terrain with scattered features, useful for travel encounters, ambushes, and campsites where cover matters more than walls. Towns produce buildings and street layouts, which suit urban chases, market brawls, and "we need to get from the gate to the temple without being seen" sessions.
A practical rule: pick based on how much cover and how many chokepoints you want. If the encounter hinges on a doorway the party can hold, you want a dungeon. If it hinges on open ground and long sight lines, you want wilderness. And if you're running theater of the mind, you can turn the grid overlay off and use the map purely as a shared visual reference.
Exporting, printing, and the scale mistake everyone makes
Download gives you a full-resolution PNG at whatever grid size you chose; SVG export is also available and is the better choice if you plan to scale the map up or edit it. Because the SVG is vector, you can open it in a vector editor and drop in room numbers, trap markers, or a compass rose without pixelation.
Printing is where most people trip up. A grid size of 40 means 40 squares across the width of the image — printed at a true one-inch grid, that's a 40-inch-wide sheet. Cheaper and saner: generate at 20 to 30 tiles and scale to fit your paper, or accept a smaller square size. Always measure one square with a ruler on the first print before you commit to a whole battle map; if your miniatures are 28mm and your squares are 18mm, the table gets awkward fast.
Theme matters for print in a way it doesn't on screen. Dark is designed for monitors and will drink ink. Parchment, ink, and blueprint are all far friendlier to a home printer, and the grid overlay prints cleanly at typical laser-jet resolution.
Why browser-only matters here
Everything runs client-side: no account, no upload, no server round-trip, and no storage. Your seed and settings never leave the page, and closing the tab leaves nothing behind. That's a deliberate design choice, and it's the reason the tool stays fast even when you're mashing the seed field looking for the right cave.
If you want the same no-signup, no-install approach for other tasks, FreeOnline.fyi hosts the full set — for example the Générateur Fiche De Révision Gratuit if you're also trying to memorize spell lists or rules between sessions.
The honest summary: this is a fast, free starting point, not a cartography suite. The layouts are readable and printable but generic, and you'll still want to verify print scale and add your own notes. Used as a first draft you customize at the table, it removes the part of prep nobody enjoys — staring at a blank grid.