All Free Calculators
Choose a free calculator by topic. Each page explains the method, shows worked examples and links to related tools.
Probability & Statistics
To convert a raw score into a standardized score, probability or percentile, use the z-score calculator. For discrete success counts, start with the binomial distribution calculator; the normal approximation tool compares an approximation with the exact binomial result.
Retirement & Savings
Worked Probability Examples
What is the probability of getting exactly 3 heads when a fair coin is flipped 10 times? Read the probability of exactly 3 heads in 10 coin flips worked solution.
If a fair six-sided die is rolled 4 times, what is the probability that at least one roll is a six? Read the probability of at least one six in 4 dice rolls worked solution.
In a sample of 20 independent items, each with an 8% defect probability, what is the chance that exactly 2 are defective? Read the probability of exactly 2 defective items in 20 worked solution.