OSRS Drop Rate Calculator

Calculate the chances of receiving rare drops based on a 1-in-X drop rate and your kill count.

Drop Information
Enter drop rate and your current kill count

Example: Enter 512 for a 1/512 drop rate

How many times have you killed this boss or monster?

Popular OSRS Drop Rates:

  • Dragon Warhammer (Shamans): 1/5,000
  • Twisted Bow (CoX): 1/1,200
  • Abyssal Whip: 1/512
  • Dragon Defender: 1/100
  • Bandos Chestplate: 1/381
Clockwork
Probability Analysis
Your drop chances and RNG luck
17.76%

Chance of Getting Drop

82.2420%

Chance of NOT Getting the Drop

(Use this to show how unlucky/dry you are!)

Expected kills (drop rate):512
50% chance at:355 kills
90% chance at:1178 kills
99% chance at:2356 kills
Understanding OSRS Drop Rates and Probability

Drop rates in Old School RuneScape describe the rarity of items from monsters and bosses. A "1/512" drop rate means each kill has a 1 in 512 chance independently. That doesn't mean you'll see the drop after 512 kills — luck can be wildly inconsistent, and many players post about going absurdly "dry" well past the expected value.

How Drop Rate Probability Works

The chance to have gotten the drop after a number of kills is calculated as 1 - (1 - 1/droprate)^killcount. That means at the expected kill count (e.g. 512 for a 1/512 rate) you're only ~63% likely to have seen the drop; at 2× the drop rate you're ~86% likely.

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