Probability Calculator

Calculate probability from favorable and total outcomes

Favorable Outcomes

Total Outcomes

How many ways to choose r items from n items (order doesn't matter)

Total Items (n)

Items to Choose (r)

Probability of getting exactly X heads in N coin flips

Number of Flips

Desired Heads

Formula

P = Favorable / Total | nCr = n! / (r!(n-r)!) | nPr = n! / (n-r)!

How do I calculate probability?

Probability = Favorable outcomes / Total outcomes. For example, rolling a 6 on a die: 1 favorable / 6 total = 16.67%.

What is the difference between combinations and permutations?

Combinations: order doesn't matter (choosing a committee). Permutations: order matters (ranking contestants). nPr >= nCr.

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