How to use the geometric distribution calculator
Find the probability that the first success occurs on trial k. Enter success probability, trial number k in the fields above; the p(first success on trial k), expected trials are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- p — Success probability
- k — Trial number k
Worked example
With success probability = 0.2, trial number k = 5, the calculator gives p(first success on trial k) ≈ 0.08192; expected trials ≈ 5.
Frequently asked questions
What is the formula for the geometric distribution calculation?
P(first success on trial k) = (1-p)^(k-1) × p. Expected trials = 1 / p. Here p is success probability, k is trial number k.
What inputs do I need for the geometric distribution calculator?
You need success probability, trial number k. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.