Have you heard of "Catan," the globally popular board game?
I don't usually play board games, but after playing with some old friends over the holidays, I was completely hooked before I knew it.
Catan has a simple premise: players place settlements on a board made of 19 resource tiles, roll two dice each turn, and any player with a settlement adjacent to a tile matching the dice total collects resources.
By spending resources to build roads and placing new settlements along those roads, you can collect even more resources.
What becomes critical here is the tile placement and number distribution. If the same type of resource tiles are adjacent, or if high-probability numbers (6 and 8) end up next to each other, certain players can dominate resource collection and the game balance falls apart.
To create a fairer game, tiles need to be carefully placed so that probabilities don't skew too heavily in any direction.
That's why I built the "Catan Board Generator" -- a tool that mathematically generates "fair tile layouts" in an instant.
[June 2025 Update] v2.1.0 introduces resource balance visualization and improved generation quality! Building on v2.0.0's Expansion (5-6 player) support and UI improvements, even higher quality board generation is now possible.
What Is the Catan Board Generator?
This tool is a web app that automatically generates Catan boards. It randomly places both resource tiles and number tokens at once, and you can also reshuffle just the numbers. While following the official rules -- such as "keep 6 and 8 apart" and "avoid too many consecutive same resources" -- it aims to create reasonably balanced layouts. When you find a board layout you like, you can save it as an image.
v2.0.0 adds support for the Expansion (5-6 players) in addition to the Standard (3-4 players), along with major UI improvements.
Features
- Supports both Standard and Expansion -- switch between 3-4 player (19 tiles) and 5-6 player (30 tiles)
- Automatic shuffling of resource tiles and number tokens
- "Shuffle Numbers Only" to keep the resource layout while changing numbers
- Strict avoidance of adjacent 6 and 8
- Advanced balancing to minimize probability bias
- Two-column layout for greatly improved usability
- Responsive design -- optimized for PC, tablet, and mobile
- Save as a high-resolution image (2000x2000px)
How to Use
- Go to Catan Board Generator
- Select a board type -- Choose "Standard" or "Expansion (5-6 players)"
- Click the Shuffle button to randomly place resource tiles + number tokens
- To keep the resource layout but change the numbers, click the Shuffle Numbers Only button
- To save as an image, click the Save Image button
Placement Rules in Detail
This tool builds on the official rules while adding custom balancing algorithms for a fairer and more strategic gameplay experience.
Basic Placement Rules
- No adjacent same resources: Same resource tiles (forest, pasture, hills, mountains, fields) are never placed next to each other
- No adjacent specific numbers: High-probability "6" and "8" as well as low-probability "2" and "12" are kept apart
- No duplicate numbers on same resource: The same number won't be assigned to the same resource type more than once
Advanced Balancing
- High-probability number distribution: "6" and "8" are distributed evenly across resource types to prevent concentration on a single resource
- Intersection expected value equalization: The value of "intersections" (where 3 tiles meet) is adjusted so that no area has an extremely low total probability
- Per-resource number quality: Prevents poor numbers (2, 3, 11, 12, etc.) from clustering on a single resource type, guaranteeing a minimum production expected value for each resource
- Probability distribution optimization: Fine-tunes each resource type's production probability to approach the ideal ratio
Display Details
- Number probabilities: The dots below each number token represent that number's probability (out of 36 possible dice combinations)
- High-probability highlighting: The particularly high-probability "6" and "8" are displayed in red
- Visual clarity: Each tile is color-coded by resource type for easy board comprehension at a glance
v2.0.0 Expansion Support (2025/06/07)
In the June 2025 update, v2.0.0 was released. Key improvements include:
Expansion Features
- Tile count: Increased from 19 to 30 tiles
- Resource composition: Additional resources of each type enable more diverse strategies
- Number tokens: Additional numbers provide more placement options
- Desert tiles: Increased from 1 to 2
Other Improvements
- Two-column layout: On desktop, the control panel and board display are separated for much better usability
- Responsive design: Layout adapts to different device sizes
- Dynamic parameter adjustment: Generation algorithm parameters are automatically tuned based on board size
- Optimized search space: Expansion mode uses 2.3x more search steps for stable generation
- Performance improvements: Coordinate calculation caching and algorithm optimization
- Error handling: Proper feedback and retry functionality when generation fails
This allows the Expansion board to be generated at the same quality level as the Standard version.
v2.1.0 Improved Fairness + Resource Balance Visualization (2025/06/12)
In the June 12, 2025 update, v2.1.0 was released. Key improvements include:
- Resource balance visualization: Added a statistics section showing "resource production likelihood," scoring and displaying each resource's production expected value
- Improved fairness: Set minimum thresholds for per-resource total production expected values (Standard: 11, Expansion: 16) to prevent any resource from being extremely disadvantaged
- Faster processing: Introduced Web Workers to speed up and stabilize board generation calculations
These improvements make it possible to more accurately evaluate generated board quality, enabling fairer and more strategic gameplay.
v2.2.0 Balance Chaos Option (2025/06/14)
In the June 14, 2025 update, v2.2.0 was released. Key improvements include:
- Balance Chaos option: A new "Balance Chaos" option that intentionally allows resource and number bias. By default, the fairest possible board is generated, but enabling this option lets you create "chaotic boards" with extreme resource or number imbalances.
- Resource expected value balance: Adjustable minimum thresholds for each resource's production expected value, letting you choose the degree of imbalance.
- Resource adjacency control: Toggle whether same resources can be placed adjacently.
- Number adjacency control: Toggle whether high-probability or low-probability numbers can be placed adjacently.
This allows the tool to accommodate not only balanced, fairness-focused play but also novelty games and advanced variant rules.
Use the "Balance Chaos" option to enjoy intentionally unfair boards or highly strategic layouts.
Summary
The "Catan Board Generator" helps you avoid the problem of clustered 6s and 8s or biased resource tiles, letting you quickly determine your board layout.
v2.0.0 added Expansion support for 5-6 player games, along with UI improvements for better usability. v2.1.0 introduced resource balance visualization and improved generation quality for fairer, more strategic board generation.
It's perfect for cutting down setup time and getting straight to playing.
Usage Notes
This tool is designed to aim for a fair gaming experience, but the "optimality" of a board may vary depending on player strategy and preferences. The generation logic includes probabilistic elements, so please verify the final board balance yourself before playing.
May your Catan experience be smoother and more enjoyable!