✓ Effortless Math · Free Tool

Geometric Distribution Calculator

Find P(X = k) and cumulative probabilities for the trial of the first success — plus the mean, variance, standard deviation, and a chart.

P(X = k) = (1 − p)k−1 · p
p = success prob p ,  k = trial k

p is the probability of success on each trial (0–1). k is the trial on which the first success occurs (k ≥ 1).

Results

P(X = k)
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P(X = k)
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P(X ≤ k)
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P(X > k)
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Mean (1/p)
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Variance
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Std. deviation
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Distribution P(X = i)

Step-by-step