Loot Drop Calculator
Enter an item's drop chance and your number of attempts to calculate the probability of getting the drop — and the expected number of tries.
Drop Rate Probability Calculator
Understanding Loot Drop Rates
A drop rate is the percentage chance an item drops from a specific enemy, chest, or activity on a single attempt. A 1% drop rate means each kill or run has a 1-in-100 chance of yielding the item. However, probability doesn't guarantee the item will drop within the expected number of runs due to the nature of independent random events.
The "Bad Luck" Problem
Even with a 1% drop rate and 100 attempts, your chance of getting the item is only ~63.4% — not 100%. This is because each attempt is independent. After 200 attempts, the probability rises to ~86.6%, and after 300 to ~95%. Some games implement "pity systems" that guarantee a drop after a set number of failed attempts to combat this variance.
Formula Used
The probability of getting at least one drop in N attempts with drop rate R is: P = 1 − (1 − R)^N. This is the complement of the probability of getting zero drops in N attempts. The expected number of attempts to get one drop is simply 1 ÷ R.