Decision wheel
Percentage Spinner — Spin with Custom Odds
Give each outcome its own percentage chance, then spin — the free percentage spinner for raffles, giveaways, games, and probability practice. No sign-up.
Odds You Choose Before You Spin
A Percentage Spinner is a free online wheel that lets you assign an exact percentage chance to each outcome before you spin. A plain 50/50 wheel, or any wheel with equal segments, gives every outcome the same odds — two options mean 50% each, four options mean 25% each, and so on. A percentage spinner breaks that symmetry on purpose: you decide the odds up front, whether that's a 90%/10% split, a 60%/30%/10% split, or anything else, and the wheel's segments resize to match.
- Grand prizeweight 5 of 100 → 5%5%
- Runner-upweight 25 of 100 → 25%25%
- Try againweight 70 of 100 → 70%70%
This is the demo wheel loaded above: three outcomes with weights of 5, 25, 70, which the tool normalizes to the segment sizes shown. Change any weight and every percentage — and every segment — recalculates instantly.
From a Blank Wheel to a Set of Real Odds
Setting up the percentage wheel spinner takes three steps. First, add the outcomes you want on the wheel — at least two, with no real upper limit. Second, assign each outcome a value from 1 to 100 using the slider or input field; this value represents its share of the total odds. Third, click Spin and watch the wheel land on a result.
Weights you set
- Grand prize
- 5
- Runner-up
- 25
- Try again
- 70
Normalization
- Sum: 5 + 25 + 70 = 100
- Each weight ÷ total = that outcome's share
Odds shown
- Grand prize
- 5%
- Runner-up
- 25%
- Try again
- 70%
You do not need your numbers to add up to exactly 100 — the tool normalizes whatever you enter, as shown above with weights that only sum to 100.
Percentage Spinner vs. Weighted Decision Wheel
The Percentage Spinner and our Weighted Decision Wheel both let you set a value per option and spin for a result matching those odds, but they're built for opposite directions of that same math.
| What differs | Percentage Spinner | Weighted Decision Wheel |
|---|---|---|
| Starting point | A number you already know (a stated rate) | A preference — "I like this one a bit more" |
| Framed around | Games, raffles, giveaways, probability demos | Personal decisions — jobs, purchases, plans |
| The demo wheel's Grand prize | 5% exact, stated in advance | Would be set by how strongly you lean toward it |
Where a Stated Percentage Beats Equal Odds
e.g. 5% grand prize
Raffles and giveaways
Give a grand prize a low percentage chance and consolation prizes higher odds, mirroring how real raffles are structured.House rules
Games with weighted odds
Board game house rules, drinking-game-style party wheels, or trivia formats where some results should be rarer than others.Classroom
Probability demonstrations
Set a known percentage and spin repeatedly to see how often it actually comes up, making abstract probability concepts concrete.No real stakes
Simulated odds scenarios
Simulate odds-based scenarios — like a "chance of rain" or "chance of success" model — without any real money or stakes involved.
Keeping Percentages Fair and Legible
- Make Odds Match Intent: If a prize is meant to feel rare, keep its percentage low (5-15%). If two outcomes should feel roughly equal, keep their values close together rather than exactly identical.
- Round Numbers Are Easier to Trust: Odds like 10%, 25%, or 50% are easier for participants to understand and verify than oddly specific numbers like 13.7%.
- Disclose the Odds When It Matters: For raffles and giveaways, telling participants the percentage chance for each prize in advance builds trust and avoids disputes about fairness.
- Test with Multiple Spins: Before using the spinner for something official, open "Simulate & Calculate Odds" to run 10, 100, or 1,000 spins instantly and confirm the outcomes behave the way you expect.
- Paste Long Lists: For more than a handful of outcomes, use "Paste a List" under Edit Options — one "Prize, 5" line each, or two columns copied straight from a spreadsheet.
- Keep the Outcome List Manageable: Very small percentages (under 2-3%) on a wheel with many outcomes can be hard to read visually, even though the underlying math is still correct.
How a Percentage Becomes an Outcome
Each spin runs the same four-step process: your browser generates a random number using JavaScript's built-in Math.random(), that number is checked against the percentage ranges you set (a 20% outcome occupies 20% of the possible values), the matching outcome is selected, and the wheel animates a rotation that lands the pointer on it. The animation itself has no influence on the result — the outcome is already decided the instant you click Spin, so speeding up or slowing down the animation would never change which outcome wins.
This level of randomness works well for entertainment, games, informal raffles, and classroom probability demonstrations, since Math.random() only needs to feel fair, not prove it. It carries no cryptographic guarantees and no independent audit, so for a raffle with real prizes or legal stakes, use a purpose-built, audited random-drawing service instead of any browser-based tool, including this one.
Setting Odds: Common Questions
No. The percentage spinner automatically normalizes whatever values you enter. If you give one outcome a value of 3 and another a value of 1, the wheel treats that as a 75%/25% split even though the raw numbers only add up to 4. You can type numbers that already sum to 100 if you want the display to match exactly, but it is not required for the odds to work correctly.
Last updated October 11, 2026. Something wrong with this tool, or a feature you need? Tell us — reported problems are looked into within 24 hours (corrections policy).