Probability Calculator
Calculate the probability of an event from its favorable and total outcomes.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter the favorable and total outcomes to find the probability, percentage, and odds.
Your result
0.167
Probability
As a percentage16.667
Odds5:1 against
AI explanation
Formula
Probability = favorable outcomes ÷ total outcomesWorked example
Rolling a specific number on a 6-sided die
| Field | Value |
|---|---|
| Favorable outcomes | 1 |
| Total outcomes | 6 |
| Probability | 0.16666667 |
| As a percentage | 16.666667 |
| Odds | 5:1 against |
Assumptions
- Assumes all outcomes are equally likely (classical probability) — for outcomes with different likelihoods, this simple ratio doesn't apply.
Frequently asked questions
What is classical probability?
It's the simplest probability model: the number of favorable outcomes divided by the total number of equally likely outcomes, like the chance of rolling a specific number on a fair die.
What does "odds" mean here?
Odds express the ratio of unfavorable to favorable outcomes — "5:1 against" means for every 1 favorable outcome, there are 5 unfavorable ones.
Can this handle probabilities of combined events (like "A and B")?
No — this calculates a single event's probability from its outcome counts. Combined-event probability depends on whether the events are independent, mutually exclusive, or conditional, which needs a different formula for each case.