OSRS Drop Rate Calculator
Calculate drop probabilities, dry streaks, and kills needed for any drop rate — including boss pets, weapons, and armour
Drop Rate
Probability Calculator
Kills for Target Probability
How Dry Are You?
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Frequently Asked Questions
01How does the dry calculator work?
The dry calculator uses the binomial probability formula: P(at least 1 drop) = 1 − (1 − rate)^kills. To calculate how dry you are, it computes the probability of NOT getting the drop after N kills. The 'How many kills' calculator finds the kills needed for a target probability (default 95%).
02What does 'X kills without drop' mean?
This calculates the cumulative probability of going X kills without receiving the drop. For example, if a drop is 1/1000 and you've done 2000 kills without it, there was only a ~13.5% chance of being that dry. You'd be in the ~86.5th percentile of unluckiness.
03Why does 95% probability need so many kills?
For a 1/N drop rate, you need approximately 3× N kills for a 95% chance of getting at least one drop. This is because each kill is independent — past kills don't affect future ones. The drop rate stays constant regardless of how many kills you've done. Note: some drop rates have been updated by Jagex (e.g., Dragon warhammer is now 1/3,000).