Calculate Warhammer 40k dice probabilities, wound rolls, and save chances with this free, fast, and accurate tabletop wargaming statistics tool.
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Technical Specification: 40k Dice Probability & Wound Tool
Overview
A clean, professional, single-file browser application designed to help tabletop gamers calculate the mathematical expectancy of their attack sequences. The app features a clean light-mode interface with real-time reactive calculations.
Key Features
- Step-by-Step Attack Sequence: Input fields for Attacks, BS/WS, Strength vs. Toughness, AP, Save/Invuln, and Damage.
- Real-Time Probability Matrix: Instant calculation of probability to hit, wound, pass save, and total expected damage.
- Expected Value Visualizer: Bar charts or percentage indicators showing the average damage output per attack run.
- Modifier Support: Toggles for rerolls (Hit/Wound), +1/-1 modifiers, and critical hit/wound thresholds.
- Responsive Design: Mobile-first grid layout that stays usable on phones during gaming sessions.
UI Layout
- Header: Simple title: "Warhammer 40k Attack Probability Calculator".
- Input Panel (Left/Top): Grouped inputs using cards.
- Section 1: Attacker Stats (Attacks, Skill, Strength, Damage).
- Section 2: Target Stats (Toughness, Save, Invuln, AP).
- Section 3: Modifiers (Rerolls, +/- 1s).
- Results Panel (Right/Bottom): A summary box showcasing "Expected Hits", "Expected Wounds", "Expected Damage Through", and "Save Probability".
Color Palette (Light Mode Only)
- Primary Blue:
#2563eb(Call to action buttons and active inputs). - Background:
#f8fafc(Off-white page background). - Card Background:
#ffffff(Clean white, high-elevation shadow). - Text:
#1e293b(Dark slate for high readability). - Border:
#e2e8f0(Subtle gray for input fields). - Accent:
#10b981(Green for success/positive results).
Animations & Transitions
- Reactive Updates: Use CSS
transition: all 0.2s easeon result fields so numbers change smoothly when inputs are modified. - Micro-interactions: Subtle scale-up on button hover; inputs show a faint blue glow (
box-shadow) when focused.
Development Constraints
- Single File: All HTML, CSS, and Vanilla JS must reside in one file.
- No Persistence: Use only transient JavaScript state variables. NO
localStorage,sessionStorage, or cookies. - Sandboxed Compatibility: The app runs in an iframe; avoid any browser functions that might trigger security policies (e.g., alert/prompt—use custom HTML modals instead).
- Library Usage: Use Tailwind CSS via CDN for rapid styling and layout consistency.
- Responsive: The layout must switch from two columns (desktop) to one vertical stack (mobile) using CSS media queries.
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Frequently Asked Questions
Everything you need to know about using this application.
How does the Warhammer 40k probability calculator work?
This tool utilizes standard statistical probability formulas to simulate the attack sequence of a unit. By inputting the number of attacks, ballistic skill or weapon skill, and strength versus toughness values, it calculates the statistical likelihood of successful hits, wounds, and failed saves. It provides an aggregate view of your offensive efficiency, helping you decide which unit is best suited to take down specific targets on the tabletop. Because it calculates expected averages rather than single rolls, it is perfect for planning your turns during competitive play.
Can I calculate wound rolls against different toughness values?
Yes, the calculator allows you to manually adjust both the strength of your attacks and the target's toughness rating. This is essential for comparing the efficiency of different weapon profiles against common infantry versus heavy armored vehicles. The tool instantly updates the probability matrix as you tweak variables, allowing for rapid A/B testing of your unit's damage output. Whether you are attacking a high-toughness monster or a swarm of infantry, the math provides clear insights into your expected damage yield.
Is this tool compatible with Warhammer 40,000 10th edition?
Yes, this probability engine is designed to accommodate the current 10th edition ruleset. It includes modifiers for hit and wound rolls, saves, and invulnerable saves, mirroring the current core rulebook's attack sequence order. We focus on the mathematical foundations of the game, meaning the logic remains accurate regardless of evolving meta shifts or points adjustments. It is a system-agnostic calculation engine built specifically for the d6-based mechanics used in modern wargaming.
Does this tool require an internet connection or account?
This is a 100% client-side application that functions entirely within your web browser. No data is sent to a server, and you do not need to create an account or provide personal information to use the calculator. All calculations happen in real-time on your device using JavaScript. This approach ensures maximum privacy and allows you to use the tool in areas with poor internet connectivity, such as gaming conventions or local hobby stores.
