Expected Attempts for Drop Calculator

How many tries should you expect, on average?

For any fixed-probability random event with no memory of past attempts (each try is independent), there's a simple formula for the average number of tries needed before the first success.

Worked example

For a 1% drop rate:

Expected Attempts = 1 / 0.01 = 100.0 attempts

Frequently asked questions

Does this mean I'm guaranteed the item by attempt 100? No - this is an average (the mean of a geometric distribution), not a guarantee. Some players get lucky and receive the item on attempt 1, while others may need several times the expected number before succeeding, purely by chance.

What's the probability I still haven't gotten it after the expected number of attempts? Interestingly, there's roughly a 37% chance of still not having succeeded even after exactly the expected number of attempts (1/e, from the properties of geometric distributions) - this is a common source of frustration and the reason "bad luck" streaks longer than the average feel so common.