Statistics Calculator

Probability Calculator

Calculate probabilities, combinations, permutations, and binomial distributions with visual representations.

Favorable Outcomes

Total Outcomes

Learning Guide

Probability measures the likelihood of an event occurring. It ranges from 0 (impossible) to 1 (certain), often expressed as a percentage.

P(A) = Favorable outcomes / Total outcomes

Example: Rolling a 6 on a fair die = 1/6 ≈ 16.67%

Selecting r items from n items where order does NOT matter.

C(n,r) = n! / (r! × (n-r)!)

Example: Choosing 3 people from 10 = C(10,3) = 120 ways

Arranging r items from n items where order DOES matter.

P(n,r) = n! / (n-r)!

Example: First 3 places in a race of 10 = P(10,3) = 720 ways

Probability of exactly k successes in n independent trials.

P(X=k) = C(n,k) × p^k × (1-p)^(n-k)