OSRS Dry Streak Calculator
Calculate the probability of going dry on rare drops in Old School RuneScape
OSRS Dry Streak Calculator
Calculate your chances of going dry on OSRS drops
Enter the drop rate in any format
Number of kills/attempts you've made
Understanding OSRS Drop Rates and Dry Streaks
In Old School RuneScape (OSRS), a "dry streak" refers to going many kills without receiving a specific drop. This calculator helps you understand the probability of experiencing such streaks and manage your expectations while grinding for rare items.
Drop rates in OSRS are typically expressed as fractions (like 1/512 for many boss pets) or percentages. Each kill is an independent event, meaning your previous kills don't affect your future chances - the drop rate remains constant.
Many players fall victim to the "gambler's fallacy," believing they're "due" for a drop after many failed attempts. In reality, each kill has the same probability regardless of your history. A 1/512 drop rate means you have a 0.195% chance per kill, whether it's your first or thousandth attempt.
The expected number of kills (drop rate) is an average - about 63% of players will get the drop by this point, while 37% will go "dry." Going twice the drop rate dry happens to about 13.5% of players, which is more common than many realize.
This calculator uses binomial probability to determine your chances. Remember that RNG (Random Number Generation) can be streaky - both good and bad luck are part of the game. Use this tool to set realistic expectations and plan your grinds accordingly.
Frequently Asked Questions
Going dry means not receiving a specific drop after many attempts. For example, if a boss has a 1/128 drop rate for an item and you've killed it 300 times without getting the drop, you're experiencing a dry streak.
Drop rates are usually shown as fractions (1/X). A 1/512 drop rate means you have 1 chance in 512 to get the item per kill, or about 0.195%. Some rates are shown as percentages directly.
No, each kill is independent. Going 1000 kills dry doesn't make your next kill more likely to drop the item. The probability remains the same for every attempt.
Going up to the drop rate (e.g., 512 kills for a 1/512 item) without getting the drop happens to about 37% of players. Going twice the drop rate dry happens to about 13.5% of players. These are more common than you might think!
This calculator uses exact binomial probability formulas, the same math that governs OSRS drops. However, it assumes the published drop rates are accurate and that Jagex's RNG is truly random.