D&D Combat Balancer 

 A Monte‑Carlo–driven combat analysis tool for Dungeon Masters who want accurate, data‑backed encounter balancing. This simulator runs 150,000 batched combat tests to determine whether a party survives a given encounter, achieving roughly 99.5% accuracy in predicting lethality. 

 What Is This? 

 This tool is a full‑fidelity combat probability simulator for tabletop RPGs (D&D‑style systems). Instead of guessing encounter difficulty or relying on vague CR guidelines, the simulator: 

•  Models your party and enemies 
•  Supports class features, feats, spell slots, gear, and monster stat blocks 
•  Tracks positioning, range, movement, and attacks of opportunity on a 2D grid
• Resolves attacks, spells, AoE, DoT, conditions, and immunities using 5E rules 
• Runs thousands of automated combat rounds 
• Allows copying combatants on either side for fast encounter setup
• Caps AC at 18 to maintain 5E balance 
• Produces statistical results you can trust 

 It’s built for DMs who want real math, not gut feelings — and who want simulations that behave like actual 5E combat, not abstract DPR calculators. 

Why Does It Exist? 

 Traditional encounter‑building rules are notoriously unreliable. CR ratings don’t scale well, party composition varies wildly, and even “balanced” fights can swing out of control. Add in class features, feats, AoE spells, positioning, and monster abilities, and the gap between theory and reality becomes enormous. 

This simulator solves that by: 

• Using Monte Carlo simulation, the same technique used in finance, physics, and AI
• Running 150k+ combat iterations to smooth out randomness 
• Modeling real 5E combat behaviors, not simplified abstractions 
• Incorporating class‑based logic, user‑defined AI, and monster card data 
• Handling resistances, vulnerabilities, immunities, and special effects 
• Supporting multiple targets, AoE templates, DoT, focus logic, and range rules
• Allowing pre‑built and custom monsters, gear, and feats
• Giving you a clear probability of party death 

If you’ve ever wondered: 

• “Is this boss too strong?”
• “Will the wizard get one‑shot?”
• “Does this AoE wipe the party?”
• “How does this fight change if the rogue actually uses Stealth?”
• “What happens if the barbarian rages and the cleric conserves spell slots?”

…this tool answers those questions with data, not guesswork.

How It Works

1. You define the combatants 

• The simulator takes in: Party stats (27‑point buy or 4d6) 
• Class features, feats, and gear 
• Monster stats (pre‑built or custom)
• Behavior profiles (class‑based or user‑defined)
• Combatants can be duplicated instantly to create groups, swarms, or reinforcement waves. 

2. It runs 150,000 Monte Carlo simulations 

Each simulation: 

• Rolls initiative
• Alternates turns using 5E action economy
• Moves units on a 2D grid
• Triggers attacks of opportunity
• Resolves melee, ranged, and spell attacks
• Applies damage, DoT, conditions, and immunities
• Tracks spell slot usage and class‑specific abilities
• Evaluates focus logic and target selection
• Ends when one side wins

This is repeated 150,000 times to generate a statistically meaningful result.

3. It analyzes the outcomes

After all simulations complete, the tool reports the overall encounter winnability.

You can compare encounters, tweak variables, and iterate until the fight feels right. 

Accuracy

The simulator’s 150k‑run Monte Carlo approach yields roughly 99.5% accuracy in predicting whether you will cause a TPK during the encounter. Because it models real 5E mechanics — not simplified abstractions — its predictions align closely with actual table outcomes. 

 UI, SFX, and VFX Layer 

 The simulator includes a full wxWidgets‑based graphical interface. To enhance clarity and immersion during simulations, the tool features: 

Sound effects for interactions and key events

Pixel‑art visual effects that animate actions and outcomes

A 2D block‑based combat renderer for spatial visualization

Background music to create a cohesive testing atmosphere

These additions do not alter the underlying math or simulation logic — they simply make the experience more intuitive and engaging while preserving analytical accuracy.