Drop Rate Calculator
At the expected number of attempts, you are only 63% there.
Work out Drop Rate. At the expected number of attempts, you are only 63% there. Names the misconception directly.
Chance of at least one in 100 attempts
63.4%
Expected wait 100 attempts — but only 63.4% certain by then
The number worth internalising is that after the expected number of attempts you have only a 63% chance of having seen the drop. That figure is 1 − 1/e, it holds for any drop rate, and it is why grinding to the average so often feels like being cheated. Each attempt is independent, which means bad luck does not build up credit. A hundred failures do not make the next attempt more likely — the distribution is memoryless, and any feeling of being 'due' is exactly the gambler's fallacy. Reaching 99% certainty takes about 4.6 times the expected number of attempts. A 1% drop expects 100 attempts and needs 458 before you can be reasonably confident, which is why long tails on drop tables generate so much frustration.
How the Drop Rate Calculator works
Odds of seeing a drop over repeated attempts, with the attempts needed for 50%, 90% and 99% certainty. The 63% figure at the expected number is the one that explains why grinding feels rigged.
Also known as: how many kills for a drop · 1 percent drop rate odds · am i due a drop · how long to farm this item
Frequently asked questions
How many attempts for a 1% drop?
100 on average, but only a 63% chance of having seen it by then. For 90% certainty you need 229 attempts, and for 99% you need 458.
Why is it only 63% at the average?
Because the distribution is geometric with a long tail. The figure is 1 − 1/e and it holds for any drop rate — a mathematical fact rather than a quirk of any particular game.
Am I due a drop after many failures?
No. Each attempt is independent and the distribution is memoryless, so a hundred failures do not make the next attempt more likely. That feeling is the gambler's fallacy.
Why do some games use pity systems?
Precisely because of this. Pure random drops produce players who are far past the average through no fault of their own, and a guaranteed threshold caps that frustration.
How many attempts to be reasonably sure?
About 4.6 times the expected number gets you to 99%. That multiple is constant regardless of the drop rate, which is worth knowing before starting a grind.
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