What are the odds?

This is a simple calculator that helps you understand what drop chance in Warframe actually means. Use the form below to calculate the chance of getting an item once in multiple runs.



chance in one run


chance of succeeding at least once in 10 runs


chance of succeeding at least once in 20 runs


chance of succeeding at least once in 30 runs


chance of succeeding at least once in 4 runs, equals 4 tenno equipping the same relic of the same refinement

123 runs

to have a 90% chance to get the item at least once

423 runs

to have a 99% chance to get the item at least once

Harrow Systems BP drop chance from Memphis / Phobos
Calculatei 7.52%
Fleeting Expertise drop chance from Orokin Vault
Calculate 4.17%
Shotgun riven drop chance from sortie
Calculate 1.36%
Imperator Vandal Receiver drop chance from Fomorian Sabotage
Calculate 2.01%
Nitain Extract drop chance from rotation C Cache Plato / Lua
Calculate 1.29%
Oberon Prime Systems drop chacne from Axi O1 Radiant
Calculate 10%

The math behind the chance
The drop chance for each run stays always the same. But each repeated run with the same drop chance increases your chance of being successful. The calulation is done by using the fail chance and put it to the power of runs.
A 10% drop chance item has a 90% probability (0.9) to not drop. For ten runs this means 0.910 to not drop. This results in 0.35, meaning 35% chance of not succeeding in 10 runs. And this again means 65% chance of succeeding (at least once) in 10 runs.
The math behind number of runs
The calculation of the number of runs it takes you to have 90 or 99 percent chance of succeeding (getting a drop) is a bit more complex because it involves logarithmic calculations.
The probability of something not droping is used a logarithmic base and one minus the percent chance you want to calculate is used in the operator.
To calcate the number of runs needed to achieve a 95% chance to succeed at least one for an item with 10% drop chance that results in log0.9(1-0.95) = 28.43 runs.
You want to dig deeper into drop chances?

The simple odds calculator is not perfect. It provides a simplified view of drop chance. If you want to nerd out on the subject here are some additional resources: