Cumulative Probability Calculator

Answer questions like "if a drop has a 3% chance, what are the odds I get at least one in 50 runs?". The calculator uses the binomial distribution: given a per-trial success probability and a number of independent trials, it computes the cumulative chance of reaching at least your desired number of successes.

How to use it

1. Enter the per-attempt success probability (for example 0.03 for 3%).
2. Enter the number of trials and the minimum successes you want.
3. Read the cumulative probability; share the link to save the calculation.