How do I calculate the chance of a Minecraft drop over many attempts?

Each attempt is independent, so the chance of getting nothing is the miss chance raised to the number of attempts. The chance of at least one drop is one minus that. For a 10 percent drop over 20 attempts, the at-least-once chance is one minus 0.9 to the 20th, about 88 percent.

Why am I not guaranteed a drop even after many tries?

Minecraft drops are independent random events with no pity timer, so a streak of misses does not raise your next chance. Even at a 10 percent rate over 30 attempts there is still roughly a 4 percent chance of getting nothing. The expected count rises steadily, but luck can run cold.

What is the expected number of drops?

Expected drops equal the drop chance times the number of attempts. At a 5 percent rate over 200 attempts you expect 10 drops on average, though the actual count varies around that mean. This is the long-run average, not a guarantee for any single run.

How many attempts do I need to be reasonably sure of a drop?

Solve for attempts where the at-least-once probability hits your target. For a 90 percent chance the formula is the log of 0.1 divided by the log of the miss chance, rounded up. The tool reports the attempts needed for 50, 90, and 99 percent confidence.

Does Looting change drop rates?

Looting raises many mob drop rates and rare-drop chances, so enter the effective rate with Looting already applied. For example a rare drop that starts at 0.5 percent rises with each Looting level. Use the in-game or wiki value for your Looting tier as the drop chance here.

Minecraft Drop Rate & Probability Calculator

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Minecraft loot is pure independent probability with no pity timer, so a rare drop can stay stubbornly absent long past its average. This calculator uses exact binomial math to tell you the real chance of at least one drop over your attempts, the expected number, and how many attempts you actually need to be confident.

How it works

Each attempt either drops the item with probability p or misses with 1 − p. Over n independent attempts:

at-least-once = 1 − (1 − p)ⁿ
expected drops = n × p
attempts for confidence c = ceil( ln(1 − c) / ln(1 − p) )

The confidence formula inverts the at-least-once equation: it finds the smallest n whose at-least-once probability reaches your target c, such as 0.90 for 90 percent.

Tips and example

A trident drops from a drowned about 8.5 percent of the time (with the trident held). Over 20 kills the at-least-once chance is 1 − 0.915²⁰, about 83 percent, with an expected 1.7 tridents. To be 90 percent sure of one you need roughly 26 kills, and 99 percent confidence demands about 52. Because there is no pity timer, always plan for the unlucky tail, not just the average.