Expected Attempts Calculator
Calculate the average attempts needed for a drop using its probability.
Average waiting time is not a countdown
If an item has a 2% chance of dropping on each independent attempt, the average wait for the first drop is fifty attempts. That statement describes many runs taken together. It does not mean the fiftieth attempt in your own run will pay out.
Why the average can feel misleading
Some players get the drop immediately. Others take far longer than the average. Those longer runs pull the average upward, which is why it is a poor substitute for a guarantee.
For a constant chance, the average attempts to first success are one divided by the probability. In percentage form, this tool uses 100 divided by your entered chance.
Use the right follow up
Start here for a quick sense of scale, then use Target Chance Planner for a probability based stopping point. If every attempt has a cost, Drop Cost Calculator converts the same average into an expected spend.
Questions about Expected Attempts Calculator
Can the answer contain a fraction?
Yes. An average can be fractional even though a single run contains a whole number of attempts.
What does a zero percent chance return?
The drop is unreachable under the entered model, so there is no finite average wait.
Does a previous miss bring me closer?
Not when attempts are independent and the chance stays constant. A separate pity system would change that assumption.