Spin The Wheel
Free Spin the Wheel. Free online tool with accurate results using verified formulas. Includes worked examples, FAQ, and instant calculations.
Formula
P(segment) = 1 / number of segments
Each segment has equal probability of being selected. With n segments, each has a 1/n (or 100/n percent) chance of being chosen.
Worked Examples
Example 1: Equal Probability Calculation
Problem:A wheel has 8 equal segments. What's the probability of landing on any specific segment?
Solution:Each segment has equal probability: P(specific segment) = 1/n = 1/8 = 0.125 = 12.5% All 8 segments sum to 100%: 8 ร 12.5% = 100% โ
Result:12.5% chance for each segment
Example 2: Weighted Probability (Multiple Entries)
Problem:You add 'Gym' 3 times and 'Rest' 1 time. What are the probabilities?
Solution:Total entries: 3 + 1 = 4 P(Gym) = 3/4 = 75% P(Rest) = 1/4 = 25% By adding 'Gym' multiple times, it has 3x the probability of 'Rest'.
Result:Gym: 75%, Rest: 25%
Example 3: Multiple Spins
Problem:What's the probability of landing on 'Pizza' twice in a row with 5 options?
Solution:Each spin is independent. P(Pizza) = 1/5 = 0.2 per spin P(Pizza twice) = P(Pizza) ร P(Pizza) = 0.2 ร 0.2 = 0.04 = 4% The more spins required, the lower the probability.
Result:4% chance of Pizza twice in a row
Frequently Asked Questions
How does the spin the wheel work?
The wheel uses random number generation to determine the rotation amount. It spins 5-10 full rotations plus a random angle, then calculates which segment is at the top when it stops. Each segment has an equal probability of being selected based on its size (equal for all entries).
Is the wheel truly random?
Yes! The wheel uses JavaScript's Math.random() which provides pseudo-random numbers. Each segment has exactly equal probability (1/n where n is the number of items). There's no weighting or bias - every option has the same chance of being selected.
How many items can I add to the wheel?
This wheel supports 2-12 items. Two items is the minimum for a meaningful choice. Twelve is the maximum to keep segments visible and readable. For more complex decisions with many options, consider using a random picker list instead.
What are good uses for a spin wheel?
Popular uses include: Deciding where to eat, picking what movie to watch, classroom random student selection, game show style prizes, team member selection, chore assignment, restaurant menu decisions, gift exchange picking, and breaking decision deadlock in groups.
Can I use this for giveaways?
Yes! The wheel is perfectly fair for giveaways. Enter participant names, spin, and the winner is randomly selected. For important giveaways, consider recording the spin for transparency. Each name has exactly 1/n probability of winning.
Why do decision wheels help with choices?
Decision wheels help by: 1) Removing the burden of choosing, 2) Making decisions fun, 3) Ensuring fairness in group decisions, 4) Breaking analysis paralysis, 5) Adding excitement to routine choices. Psychologically, outsourcing decisions to 'fate' reduces decision fatigue.
What's the math behind wheel probability?
For a wheel with n equal segments: P(any specific segment) = 1/n. With 6 items, each has 16.67% chance. With 4 items, each has 25% chance. The formula for k specific items from n segments over multiple spins follows binomial distribution.
Can I save my wheel configurations?
Currently, wheel configurations aren't saved between sessions. For repeated use, you can bookmark the page and re-enter items. Future versions may include save functionality. You can also screenshot your configuration to recreate it.
How do I ensure fair group decisions?
For fair group decisions: 1) Have everyone agree on options BEFORE spinning, 2) Let a neutral person add items, 3) Spin once and accept the result (no 'best of 3'), 4) Display the wheel visibly to all, 5) Everyone should agree in advance to honor the result.
What if I want weighted probabilities?
This wheel gives equal probabilities. For weighted chances (some options more likely), you can add the same item multiple times. If 'Pizza' should have 2x the chance, add 'Pizza' twice. Each instance adds to that option's probability.