Saikoru — Roll Dice Realistically in Your Browser
They bounce, tumble, and sometimes teeter on an edge. A true physics-simulated 3D dice roller — free, no install, and how hard you throw is up to you with the power gauge.
Loading 3D dice… (takes a few seconds on first visit)
Your browser does not support 3D rendering, so a simple dice roller is shown instead.
The 3D simulation works on iOS Safari 15+, Android Chrome and desktop browsers.
How to use
Pick a die type
The classic six-sided die (D6), plus the TRPG standards: D4, D8, D10, D12 and D20.
Choose how many
Roll 1 to 10 dice at once — multi-rolls like 2d6 or 8d6 in a single tap.
Set your throw power with the gauge
Tap "Roll" and a power gauge sweeps between soft and hard — tap again to throw with that exact strength. The dice drop, tumble, and whichever face lands up is your result, with totals added automatically. Place them gently or hurl them hard: your call.
Not just realistic — fairness verified over 100,000 rolls
The physics decides the result — nothing else
Many dice apps pick a random number first and then play an animation. Saikoru doesn't. Mathematically exact polyhedra are thrown inside a physics engine, and the face that settles up is the result. Every bounce, every tumble, even the occasional stubborn teeter against the tray wall — it's all the same physics real dice obey.
Every throw is generated from cryptographic randomness
Position, orientation, velocity and spin are independently generated from cryptographically secure randomness (crypto.getRandomValues) on every single roll — no pseudo-random bias can leak into the outcome.
Verified with 100,000 rolls per die
Before release, each die type is rolled 100,000 times automatically and tested with a chi-squared goodness-of-fit test. Our development rule: any die that shows statistically significant bias does not ship.
| Verification | Details |
|---|---|
| Method | Chi-squared goodness-of-fit test (5% significance level) |
| Sample size | 100,000 rolls per die type (600,000 total) |
| Result | Uniformity not rejected for all six dice (d4–d20) — no bias |
*The same 100,000-roll test is re-run every time the physics engine or parameters are updated.
FAQ
Is it truly random? Can results be manipulated?
Yes, it is truly random. The physics simulation itself produces the result — nothing is pre-selected. Throws are generated from cryptographic randomness, and neither users nor the operator can control the outcome. Fairness is statistically verified over 100,000 rolls.
How does it differ from a real die?
The shapes are mathematically exact polyhedra, and just like real dice, the face that lands up is the result. With no human throwing habits or tampering, it is arguably fairer than a physical die.
Does the power gauge change the odds?
No. Throw strength only changes how the dice bounce and tumble. Each die's orientation is drawn from cryptographic randomness on every throw, so every face remains equally likely — and fairness testing covers the whole soft-to-hard range.
Is it free? Do I need an account?
Completely free, no registration, nothing to install — it runs right in your browser.
Does it support TRPG dice?
d4, d6, d8, d10, d12 and d20 are all supported, with up to 10 dice per roll — handy for damage rolls like 8d6.
How do I read the "0" on the D10?
The D10 uses the real-world 0–9 labeling. If your game reads 0 as 10, simply interpret it that way.
How do I read the D4?
The D4 uses the bottom-face convention: the number shown around the upward-pointing vertex (which equals the bottom face) is the result. The rolled value is also displayed as a number below the dice tray.
Does it work on smartphones?
It works on iPhone (iOS Safari 15+) and Android Chrome. On browsers without 3D support, a simple dice roller is shown automatically so you can always get a result.
Choosing an online dice roller — what to look for
"RNG-style" vs "physics-simulation" rollers
Online dice tools come in two flavors: RNG-style tools that pick a number and then show an animation, and physics-simulation tools that actually tumble the dice. With RNG-style tools, the animation and the result are two separate things — which often leaves that nagging "was this really random?" feeling. Saikoru is a physics simulator: what you watch is literally what decides the result.
Fairness should be verified, not assumed
Whether physics-based or RNG-based, fairness can only be guaranteed by measurement. Saikoru rolls each die 100,000 times and runs chi-squared tests before shipping. For game nights and turn-order decisions where arguments are the last thing you want, use dice that have been tested.
No install — roll instantly
No app store download required. Open the URL and the 3D dice are ready in seconds — perfect when you left your dice at home, or when a classroom or workshop needs a quick random pick.
Made for TRPG sessions too
All the polyhedral dice used in D&D, Call of Cthulhu and other tabletop RPGs are here, with up to 10 dice per roll and automatic totals. During online sessions, screen-sharing the tumbling dice keeps the tension of a real roll.
Nothing is sent anywhere
All rolling happens locally in your browser. Results are never decided or recorded on a server.