Guides to Randomness and Fair Draws on WheelJar

How to Make a Custom Spinner Wheel

Thu, 06 Aug 2026 00:00:00 +0000

Start with the list, not the wheel

The wheel is the easy part. Open the wheel spinner, clear the demo entries and type your own, one per line. The wheel redraws as you go, so you can see immediately whether the labels are readable at the size you are working with.

Two rules make the difference between a wheel people use and one they abandon. Keep entries short — anything past about twenty characters gets squeezed into a thin slice and stops being legible on a phone. And only include options you will actually accept. A wheel loaded with aspirational choices gets overruled the first time one comes up, and a wheel that has been overruled once is never trusted again.

Is a Coin Flip Really 50/50?

Thu, 06 Aug 2026 00:00:00 +0000

The coin is fair. The toss is not.

Everyone learns that a coin flip is the definition of an even chance, and for most purposes that is close enough to true. But it is not exactly true, and the reason is genuinely surprising: the bias lives in the throw, not in the metal.

Persi Diaconis, Susan Holmes and Richard Montgomery worked out the mechanics in a 2007 paper in SIAM Review. A coin thrown by a human hand does not tumble neatly end over end. It precesses — the axis it spins about wanders, describing a cone, in the same way a spinning top leans and circles. Because of that wobble, the coin spends marginally more of its flight time showing the face that was up when it left the thumb. Catch it in your hand and that surplus shows up in the result.

Fair Ways to Pick a Giveaway Winner

Thu, 06 Aug 2026 00:00:00 +0000

The generator is not the problem

In practice, nobody argues about the random number. They argue about everything surrounding it: was my entry in the list, did that person really get five entries, did you draw twice because you did not like the first name, why did the winner turn out to be your cousin.

All of which means a fair draw is mostly a documentation exercise. The tool takes half a second; the credibility comes from what you did before and after.

How Random Is Random?

Thu, 06 Aug 2026 00:00:00 +0000

Two different jobs called “random”

Software has two kinds of random number generator, and they are built for opposite purposes.

A PRNG — pseudo-random number generator — is an algorithm that turns a small internal state into a long sequence of well-spread numbers. It is deterministic: the same starting state always gives the same sequence. That is a feature for games and simulations, where you often want to reproduce a run exactly, and it makes the generator very fast. Math.random is one of these.

Secret Santa Rules That Actually Work

Thu, 06 Aug 2026 00:00:00 +0000

Settle the budget before anything else

The draw is trivial. The budget is where Secret Santa lives or dies, and it fails in a predictable way: somebody proposes “about ten to twenty”, half the group hears ten and the other half hears twenty, and on the day one person unwraps a keyring while the next unwraps a bottle of something proper. Nobody did anything wrong and everyone feels awkward.

State one number. Not a range, not a guideline, not “whatever you like”. One number, in one message, before names are drawn — because once people know who they are buying for, the budget conversation becomes personal.

Wheel Odds Chart

Tue, 11 Aug 2026 00:00:00 +0000

Every figure on this page is generated at build time from the same arithmetic the wheel runs: a uniform draw over equal slices, with the winner left on the wheel unless you switch that off.

Odds for a wheel with equal slices, worked out from the uniform draw the spinner performs. „Spins to give everyone a turn" is the average number of spins before every option has won at least once, with the winner left on the wheel.
Options	Slice	Chance per spin	Same winner twice in a row	A repeat within 5 spins	Spins to give everyone a turn
2	180.0°	50.00%	25.00%	100.0%	3
3	120.0°	33.33%	11.11%	100.0%	6
4	90.0°	25.00%	6.25%	100.0%	8
5	72.0°	20.00%	4.00%	96.2%	11
6	60.0°	16.67%	2.78%	90.7%	15
8	45.0°	12.50%	1.56%	79.5%	22
10	36.0°	10.00%	1.00%	69.8%	29
12	30.0°	8.33%	0.69%	61.8%	37
15	24.0°	6.67%	0.44%	52.5%	50
20	18.0°	5.00%	0.25%	41.9%	72
25	14.4°	4.00%	0.16%	34.7%	95
30	12.0°	3.33%	0.11%	29.6%	120
40	9.0°	2.50%	0.06%	22.9%	171
50	7.2°	2.00%	0.04%	18.6%	225

Why does a wheel need more spins than it has names?

Because the wheel has no memory. Once eight of your ten names have won, the next spin still gives each of the ten a 10% chance, so the two names left need on average five spins each to appear — and the last one alone accounts for ten. Adding that up across every stage is the coupon collector’s sum, n multiplied by 1 + ½ + ⅓ + … + 1/n, and it grows faster than the list does.