Spin the Wheel: Random Name Picker

At the click, the tool asks the browser's cryptographic random generator (crypto.getRandomValues) for a 32-bit number and turns it into a segment number. A plain remainder would slightly favor the first segments whenever their count does not divide 2³², so the values that would create that bias are discarded and a new number is drawn: each of n segments keeps a chance of exactly 1 in n. Only then is the stop computed: 5 to 7 full turns plus the distance to the drawn segment, halting between 10% and 90% of its width so the pointer never rests on a dividing line, over 4.2 to 5.6 seconds.

The wheel counts lines, not people. A name typed twice gets two segments and twice the chance, which is exactly what “Duplicate” does in the list. “Remove duplicates” merges entries that differ only in capitals, accents or spacing and keeps the first; “Shuffle” reorders the list with the same uniform draw, which moves segments and colors but not the odds; and removing a winner deletes that one segment, not other entries with the same name.

The site's automated tests check both halves. One draws 8,000 times from 2 entries, 28,000 times from 7 and 400,000 times from 100, and fails if the frequencies drift further from equal than chance would allow, at a one-in-a-million threshold; another spins 200 wheels at each of six sizes, from 2 to 1,000 entries, and checks that the pointer always stops on the drawn segment. If you switch tabs mid-spin, the browser pauses the animation, but the winner is already fixed: when you come back, the wheel jumps to where it should be, or straight to the result.

• In class: a random name picker calls on students without anyone feeling singled out. With “Remove the winner automatically” checked, everyone gets a turn before anyone is picked twice; for two students with the same first name, add an initial, since “Remove duplicates” would keep only one of them.
• Stand-ups and retrospectives: settle the speaking order. With automatic removal on, spin until the wheel is empty; the “History” block lists each name with the time of the draw, newest at the top, so the order reads from the bottom up.
• A giveaway on a livestream or among friends: “Full screen” shows only the wheel and what the draw needs (title, button, result), which suits a shared screen. Viewers can check the link you post for doubled names, although that link shows the list, not your draw.
• Deciding where to eat: load “Meals”, swap in your own restaurants, and give the group's favorite a second segment with “Duplicate”, in plain sight of everyone at the table.
• Dares, forfeits and chores: one wheel of challenges for a party, another titled “Who does the dishes?”; with the “Yes / no” example, each answer has a 50% chance.
• A number wheel: “Numbers 1–10” picks a table, a question or a seat; type 1 to 30 yourself for a whole class. To split a group into teams in one go, a group generator is quicker than one spin per person.

• Weighting with “Duplicate”: James, Emma, Oliver, Sophia and Liam make 5 segments at 20% each. Click “Duplicate” next to James and the list becomes James, James, Emma, Oliver, Sophia, Liam: 6 segments, so James now has 2 in 6 = 33.3% and each of the others 1 in 6 = 16.7%.
• A speaking order for 4 people with automatic removal: the wheel shrinks from 4 to 3, 2 and 1 segment. Three spins are real draws; before the fourth, the tool says “Only one entry: the result is known in advance.” Each of the 24 possible orders has a probability of 1/4 × 1/3 × 1/2 = 1/24, about 4.2%.
• The same name three times in a row: with 4 entries and no removal, the chance that the next two spins repeat the first winner is 1/4 × 1/4 = 6.25%, about one run in 16. With 8 entries it drops to 1/64, roughly 1.6%. Runs like this are part of a fair draw.
• Hitting the limits: paste 1,200 lines and the counter stops at “1,000 entries”, with a red line saying “Only the first 1,000 lines go on the wheel.” A wheel of the numbers 1 to 763, with no title and the default “Vivid” colors, still fits in a link (5,994 characters of code); add 764 and the link buttons answer “Wheel too big for a link.”

• 1,000 entries and 80 characters per entry at most. Lines beyond the thousandth stay in the text box but never reach the wheel, and they are not saved: they vanish on reload, or as soon as a list action or an automatic removal rewrites the list. A longer line is cut at 80 characters, on the wheel and in what is saved.
• The link carries the whole list, capped at 6,000 characters of code: about 344 names of 10 unaccented characters, only 298 if two of those characters are accented, because accented letters take more room. It also carries the title, the colors and the automatic-removal setting, but neither the sound nor the history.
• On the largest wheel outside full screen (560 pixels across), names are written on up to 129 segments and not at all from 130 on; a narrower screen drops them sooner, and long names are shortened with an ellipsis well before that. The winner card and the history always show the full name.
• Sound is off by default. Once you turn it on, the ticks and the final chime are synthesized by the browser, at most 25 ticks per second, and they follow the device volume; on a phone, silent mode can mute them.
• Your wheel is saved in this browser only: another browser or device will not see it, a private window forgets it when closed, and clearing the site's data deletes it. The history keeps the last 50 results.
• Nothing proves afterwards that a draw took place: the history stays on your device, the link shows the list but not your result, and the tool issues no certificate for a contest's rules. For a public giveaway, spin where your audience can watch.