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Probability Calculators

Probability Calculator

Probability of A and B, A or B, not A, and exactly one — for two independent events given their individual probabilities.

Enter values

Results update as you type.

Result

P(A and B)

0.2

P(A or B)
0.7
P(not A)
0.5
P(not B)
0.6
P(exactly one)
0.5
P(neither)
0.3

About the Probability Calculator

Probability of A and B, A or B, not A, and exactly one — for two independent events given their individual probabilities.

Also known as: probability of events, p(a and b), p(a or b), chance calculator, likelihood calculator.

How to use this calculator

  1. Enter p(a), p(b).
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

P(A∩B) = P(A)·P(B) · P(A∪B) = P(A) + P(B) − P(A∩B)

Worked example

Using the values pre-filled in the calculator above:

  • P(A) = 0.5
  • P(B) = 0.4

the calculator returns:

  • P(A and B): 0.2
  • P(A or B): 0.7
  • P(not A): 0.5
  • P(not B): 0.6