Random Wheel Picker

How It Works

Every non-empty line becomes one sector of a canvas wheel, coloured from a palette derived from the site's accent hue. When you press Spin, the tool first picks the winner with a secure random draw, then computes the exact stopping angle that parks that sector under the pointer at the top, and finally plays the animation for about 3.5 seconds so the result feels earned rather than announced.

The arc maths

With n entries each sector spans 2π/n radians. The pointer sits at the 12 o'clock position (−π/2 in canvas coordinates), and sector i occupies the arc [i·2π/n, (i+1)·2π/n) rotated by the wheel's current angle. To land on winner w, the wheel stops at −π/2 − (w + ½)·2π/n plus three to five full turns for flourish — so the animation is deterministic once the winner is drawn, and the visual can never disagree with the result.

Why ease-out cubic

The spin follows 1 − (1 − t)³: fast start, long decelerating tail. It mimics a real wheel losing momentum to friction, and it keeps the last second slow enough that everyone can watch the pointer settle instead of squinting at a blur. Total duration is fixed at 3.5 s regardless of entries, so classroom attention never drifts.

Fairness: crypto, not a seeded pseudo-random

Winners come from crypto.getRandomValues — the operating system's entropy pool — with a direct uniform pick over the entry count (30 sectors max against a 32-bit draw introduces no meaningful bias). There is no seed to inspect, no repeatable sequence, and no server involved: the result is genuinely unpredictable at the moment you press Spin.

Frequently Asked Questions