Casting Dice — cast and roll dice online for D&D, Warhammer, and tabletop games
“Cast with confidence. Play with precision!”
Welcome Caster!
Choose your dice, speak the cast, and let fate answer.
Casting Dice gives you fast, provably fair dice rolls for every tabletop adventure — from a single d20 to a fistful of fireball d6s — with modifiers, advantage, saved macros and a full cast history.
Results
Click on the dice to cast…
Total
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Crit die: d20 — a natural 20 is a critical, a natural 1 is a fumble.
Quick Cast
Cast Builder
Cast History
- No casts yet — your history will appear here.
Presets & Macros
Name your current Cast Builder setup to save it as a quick-access macro (for example, “Fireball 8d6”). Presets live in memory only and reset on refresh — use “Copy presets as text” to keep a copy.
No presets saved yet.
Dice Browser
Extended and system dice — click any die to cast it. Results appear in the Results panel above and in your history.
Extended Polyhedral
Uniform 1…N dice beyond the standard set.
System Dice
FATE/Fudge, d66, and dice-pool systems.
Star Wars / Genesys Narrative Dice
Build a pool of narrative dice; opposing symbols cancel and the net result is shown (success/advantage, triumph/despair). ◇ success · ▲ advantage · ◆ failure · ▽ threat · ★ triumph · ✦ despair.
Wargaming Dice
Warhammer d3 (ceil of d6 ÷ 2), scatter and artillery dice.
Narrative & Board-Game Dice
Story dice with symbol faces and common board-game dice.
Game Master Tools
Themed Dice Sets
Recolour your dice to match the mood of the table.
Probability & Statistics
Analyse the current Cast Builder configuration — dice count, type and modifier. (Advantage is not included in the distribution.)
Multi-Group Casting & Encounters
Add several groups and cast them together — a whole encounter in one click. Save the set as an encounter to reuse it.
How to Use Casting Dice
- Quick cast: tap any die in Quick Cast (d4–d100) to cast one instantly.
- Build a cast: set the number of dice, pick a dice type, add a modifier, and choose Normal, Advantage or Disadvantage.
- Cast it: click the felt table and your dice tumble onto it in 3D, with the total below. Larger or specialist casts show as result chips instead.
- Read crits: on a d20, a natural 20 glows green (critical) and a natural 1 glows red (fumble).
- Save macros: name your current setup under Presets to make a one-tap button (e.g. “Sneak Attack 6d6”).
- Keep a record: every cast is logged in History — expand, copy or print it any time.
- Sound: flip the sound toggle in Results for cast, crit and fumble tones (on by default).
- Go deeper: open the Dice Browser for extended, system, wargaming and narrative dice, and the Game Master Tools for probabilities, multi-group encounters and themed dice.
Understanding Dice Odds
Every die here is uniform — each face is equally likely. What changes the odds is how many dice you cast and how you combine them.
What are the odds of rolling a natural 20?
Exactly 1 in 20, or 5%. The same is true of a natural 1. Over a long session those extremes feel streaky, but each cast is independent — a d20 has no memory of the last roll.
How much does advantage actually help?
Advantage casts two d20s and keeps the higher. On average it adds about +3.3 to your result, but the benefit depends entirely on the target number:
Advantage is worth most on a coin-flip check (needing 10–11), where it swings your odds by 25 percentage points. It helps least when you were nearly certain to succeed, or nearly certain to fail. Disadvantage is the exact mirror.
| You need | Normal | Advantage | Gain |
|---|---|---|---|
| 5+ | 80% | 96% | +16 |
| 10+ | 55% | 80% | +25 |
| 11+ | 50% | 75% | +25 |
| 15+ | 30% | 51% | +21 |
| 20 | 5% | 9.8% | +4.8 |
Why does 3d6 feel different to a d20?
Both average 10.5, but the shapes differ completely. A d20 is flat — every number is equally likely. Cast 3d6 and results cluster: 10 and 11 come up about 12.5% of the time each, while a 3 or an 18 appear only once in 216 casts. Multiple dice produce a bell curve, which is why systems using dice pools feel more predictable than a single d20.
What is each die normally used for?
- d4 — daggers, magic missiles, small damage steps.
- d6 — the workhorse: sneak attack, fireballs, most dice-pool systems.
- d8 — longswords, common hit dice.
- d10 — percentile tens, World of Darkness pools, many damage rolls.
- d12 — greataxes and barbarian hit dice; the least-used polyhedral.
- d20 — attacks, saves and skill checks in d20 systems.
- d100 — percentile rolls, loot and wild-magic tables.
Dice by Game System
Different games count dice in very different ways. Casting Dice handles each convention natively — here is what to reach for.
Dungeons & Dragons 5e
Use the Cast Builder for attacks and saves: one d20, a modifier, and Normal, Advantage or Disadvantage. Damage rolls are the same builder with a different die and count — 8d6 for a fireball, 2d6+3 for a greatsword. Natural 20s glow green and natural 1s glow red so crits are obvious at a glance.
Warhammer and wargaming
The Wargaming Dice group in the Dice Browser covers the Warhammer d3 (a d6 halved and rounded up), plus scatter and artillery dice. For to-hit and to-wound rolls, cast a bucket of d6s from the Cast Builder and read the individual results in the breakdown.
Shadowrun dice pools
Open System Dice and set your pool size. Casting Dice rolls that many d6s, counts every 5 or 6 as a hit, and warns you of a glitch when too many 1s appear. You get the hit count and the individual dice, so you can check the result yourself.
World of Darkness and Storyteller games
Also under System Dice. Set the pool and Casting Dice rolls that many d10s, counting 8 or higher as a success and reporting the total.
Star Wars and Genesys narrative dice
The Narrative Dice group lets you build a pool from boost, ability, proficiency, setback, difficulty and challenge dice. Opposing symbols cancel automatically and the net result is shown — success or failure, advantage or threat, plus any triumph or despair. No symbol chart needed.
FATE and Fudge
Cast 4dF from System Dice. Each Fudge die reads minus, blank or plus, giving a total between −4 and +4, with 0 the most common outcome.
Dice Rolling for Game Masters
Running a table means rolling for a lot of creatures at once, and knowing the odds before you set a difficulty.
Rolling initiative and attacks for a whole encounter
Use Multi-Group Casting in Game Master Tools. Add a group per creature type — six goblins at 1d20+2, two ogres at 1d20+5 — then cast them all in one click. Save the set as an encounter and reuse it next session instead of rebuilding it.
Choosing a fair difficulty class
Open Probability & Statistics and analyse your current Cast Builder setup before you set a DC. As a rough guide on a d20: a DC of 10 against a +3 modifier succeeds about 70% of the time, while a DC of 18 succeeds about 30%. Setting difficulties deliberately, rather than by feel, keeps encounters honest.
Keeping a record of what was cast
Every cast is logged in Cast History with a timestamp. You can copy the log as text or print it — useful for play-by-post games, or for settling a disagreement about what the dice actually said.
Frequently Asked Questions
Are the dice really random?
Yes. Every cast uses your browser’s cryptographic random number generator (
crypto.getRandomValues) with bias-free sampling, not the weaker Math.random. Each face of each die has an equal chance, so results are fair and unpredictable.Do my presets save?
Presets and history are held in memory for your current session only and reset when you refresh or close the tab. Casting Dice stores nothing on your device. Use the “Copy presets as text” button to keep a copy you can paste back later.
Which game systems are supported?
Casting Dice supports the full polyhedral set (d4 to d100) with modifiers and advantage/disadvantage, extended dice (d2, d3, d5, d7, d14, d16, d24, d30), FATE/Fudge, d66, Warhammer d3, scatter and artillery dice, Shadowrun and World of Darkness dice pools, Star Wars/Genesys narrative dice, and story and board-game dice. Game Master tools add multi-group encounter casting, probability charts, cast statistics and themed dice sets.
Can I use it on my phone?
Yes. Casting Dice is mobile-first and responsive. Controls stack into a single, thumb-friendly column on narrow screens, so you can cast comfortably at the table from any phone or tablet.
Is it free?
Completely free. There is no account, no download and no cost — just open the page and cast.
What are the odds of rolling a natural 20?
Exactly 1 in 20, or 5% — and the same for a natural 1. Each cast is independent, so a run of low rolls does not make a 20 any more likely on the next cast.
How do advantage and disadvantage work?
Advantage casts two d20s and keeps the higher; disadvantage keeps the lower. On average advantage adds about +3.3 to your result, and it helps most on a roughly even check — needing 11 or better, it lifts your odds from 50% to 75%. Both dice are shown so you can see what was kept.
Can I roll a Shadowrun or World of Darkness dice pool?
Yes. Open the Dice Browser and find System Dice. Set your pool size and Casting Dice rolls it, counting hits automatically — 5s and 6s for Shadowrun, with a glitch warning for excess 1s, or 8 and above for World of Darkness. Individual dice are always shown alongside the total.
Do you support Genesys and Star Wars narrative dice?
Yes. Build a pool from boost, ability, proficiency, setback, difficulty and challenge dice in the Dice Browser. Opposing symbols cancel automatically and the net result is shown, including triumph and despair.
Can I roll for a whole encounter at once?
Yes. Multi-Group Casting in Game Master Tools lets you add a group per creature type, each with its own dice count, die type and modifier, then cast them all together. Sets can be saved as encounters and reused.
Why do some casts show as chips instead of 3D dice?
The 3D felt table renders standard polyhedral casts of up to eight dice. Larger handfuls, advantage pairs and symbol-based dice such as FATE or narrative dice are shown as result chips instead, because a number on a chip is clearer than a crowded table.
Does Casting Dice use cookies or tracking?
Casting Dice uses Google Analytics to count visits and understand which features are used. That sets analytics cookies in your browser. Your rolls, presets and history are never stored, sent or shared — all dice logic runs entirely in your browser.