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OSRS Drop Formula:
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The OSRS (Old School RuneScape) drop formula calculates the probability of receiving at least one drop after multiple attempts. It's based on the complementary probability of not receiving the drop across all attempts.
The calculator uses the OSRS drop formula:
Where:
Explanation: The formula calculates the probability of getting at least one successful drop by subtracting the probability of never getting the drop from 1.
Details: Understanding drop probabilities helps players estimate how many attempts they might need to obtain rare items, plan their gameplay time, and set realistic expectations for item acquisition.
Tips: Enter the drop probability per attempt (between 0 and 1) and the number of attempts (must be a positive integer). The calculator will compute the overall probability of receiving at least one drop.
Q1: What does a probability of 1 mean?
A: A probability of 1 means a 100% chance of receiving at least one drop, which is only theoretically possible with infinite attempts.
Q2: How accurate is this formula for OSRS?
A: This formula accurately represents the probability calculation used in OSRS and many other games with independent drop chances.
Q3: Does killing more monsters increase my chance per kill?
A: No, each kill has the same independent chance. This formula calculates the cumulative probability across multiple independent attempts.
Q4: What's the probability of getting exactly one drop?
A: This formula calculates the probability of getting at least one drop. The probability of exactly one drop is \( k \times p \times (1-p)^{k-1} \).
Q5: How many attempts do I need for a certain probability?
A: You can rearrange the formula: \( k = \frac{\ln(1-P)}{\ln(1-p)} \) to calculate the number of attempts needed for a desired probability P.