AbraCalc

Binomial Probability: 100 Coin Flips, Exactly 50 Heads

The probability of exactly 50 heads in 100 fair coin flips is approximately 7.96%.

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How to use this tool

  1. Enter trials (n), successes (k) and probability of success (p) in the fields above.
  2. Results update instantly as you type — or click Calculate.
  3. Read your p(x = k) and the full breakdown beneath it.

Find the exact probability of getting precisely 50 heads in 100 coin flips, a classic statistics problem.

Frequently asked questions

What is the binomial distribution?
The binomial distribution models the number of successes in n independent yes/no trials, each with the same probability p of success. Classic examples: coin flips, pass/fail tests.