D&D Toolset · Browser-Based · Combat Math

MagluForge

Browser-based D&D planning tools for players and DMs: encounter simulator, DPR calculator, and action economy planner. No spreadsheets, no math, just sharper decisions at the table.

In DevelopmentSolo Developer2025
Enter the Forge ↗GitHub
magluforge.com · live
Party HP
72%
Enemy HP
18%
Round
3 / 5
Party wins84%
Avg rounds to end3.4
4
6
8
10
12
14
16
18
20
Greatsword +5 · avg 11.5
Rapier +7 · avg 9.8
Round 2 · Your Turn
Attack x2Bonus AttackMove 30ftRiposte
Action economy: +1 advantage vs single-target
Project Details
Overview

Prepping encounters and running combat math in D&D eats up time, especially for newer DMs and players optimizing builds. MagluForge is a set of browser tools that make it faster: encounter simulation, DPR comparison, and action economy analysis. Everything runs client-side with no login or backend required.

The Tools
SIM
Encounter Simulator
Test combat scenarios round-by-round and see outcome distributions
DPR
DPR Calculator
Compare damage per round across builds, spells, and attack configs, with dice distribution charts
ACT
Action Planner
Evaluate turn efficiency and spot action-economy advantages in any encounter
How It Works
I
User inputs encounter or build parameters
II
JS probability engine processes dice math and modifiers
III
Combat flow simulated round-by-round
IV
Probability distributions calculated for each outcome
V
Results rendered with Canvas-based distribution charts

All computation runs client-side. The probability engine handles advantage/disadvantage, conditional modifiers, and multi-attack sequences. The DPR calculator renders dice distributions using the Canvas API directly with no chart library.

Technical Decisions
Fully client-side, no backend: No cold starts, no hosting costs, no auth complexity. D&D tools are stateless by nature: you input parameters and get results. A backend would add friction without adding value.
Custom probability engine over a library: D&D 5e mechanics: advantage stacking, conditional modifiers, multi-attack interactions, specific spell effects, which do not map cleanly onto generic stats libraries. Purpose-built math was the only way to get accurate results.
Canvas API for charts: The DPR distribution charts use the Canvas API directly instead of Chart.js or D3. For a fixed chart type with a specific visual style, pulling in a full charting library adds load overhead without flexibility gains.
Simplified inputs for newer players: The interface was tested with less experienced players. The priority was making the tools approachable without stripping power-user functionality, which drove iterative UI changes to input labels and result breakdowns.
Challenges

D&D 5e has a lot of edge cases: advantage stacking,, conditional modifiers, multi-attack interactions. Getting those right while keeping the simulation fast required careful architecture of the probability engine so each modifier type is handled at the correct layer.

Making the interface approachable for newer players was the other major challenge. The inputs needed to make sense to someone who doesn't know what "DPR" means, while still being useful to optimizers. That balance came from iterative testing with both groups.

What's Next
  • Improved mobile layout for smaller screens
  • More tools: initiative tracker, loot generator, condition tracker
  • Refined onboarding for players new to D&D combat math