How the wheel actually works
Spinaroo is intentionally simple: a list of options, a spin, and a result. Here's what happens behind the scenes, so you can trust the outcome.
1. Picking the winner
Before the wheel even starts spinning, your browser picks a winning option using JavaScript's random number generator, giving every option currently on the wheel an equal chance — a wheel with 4 options gives each one a 25% chance, a wheel with 10 options gives each one a 10% chance, and so on.
2. Animating the spin
Once the winner is chosen, Spinaroo calculates exactly how far the wheel needs to rotate so that the winning slice ends up under the pointer at the top, adds several extra full rotations so it feels like a real spin, and animates it over about five seconds with an easing curve that starts fast and eases to a stop — the same technique used in most physical-feeling web animations.
3. What happens to your data
Your list of options is saved only in your own browser's local storage, so it's there the next time you visit that page on the same device. It is never uploaded to a server, logged, or shared — Spinaroo doesn't have accounts, so there's nowhere for it to go.
4. Why the result can be trusted
Because the winner is chosen first and the animation is just a visual reveal, there's no way to "nudge" the wheel toward a particular answer after the fact. What you see landing under the pointer matches the number that was drawn at the moment you pressed spin.