This basic calculator shows the theoretical probabilty of succeeding by repeating something with a fixed drop chance.

67.02% for 10 runs

89.12% for 20 runs

89.12% for 30 runs

Calculate 28.00%
**Ayatan Anasa Sculpture** drop chance from sortie

Calculate 7.52%
**Harrow Systems BP** drop chance from Memphis / Phobos on rotation C

Calculate 5.64%
**Khora blueprint** drop chance from rotation C (stage 8) of onslaught

Calculate 4.17%
**Fleeting Expertise** drop chance from Orokin Vault

Calculate 1.36%
**Shotgun riven** drop chance from sortie

Calculate 0.50%
**Augur Seeker** drop chance Recon Commander kill on PoE

A while back I made a video on how to use this website and on how to interpret the results. This video also covers the different aspects of probability without diving too deep into the math rabbit hole.

There is also a complete video transcript available.

The drop chance for each individual run stays the same. Repetition does not increase the drop chance as such. What it does increase is the probability to get what you want the more repetitons you do.

*But there is no guarantee for success even at 99.99% probability.*

This calculator gives you an indication of the number of tries you have to expect.

This calculator gives you an indication of the number of tries you have to expect.

The calculation of how many tries should give at least one positive result is done by using the chance to fail.

10% drop chance means a 90% probability (0.9) to fail. For 10 runs this means a probabilty 0.9^{10} to fail. 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.

10% drop chance means a 90% probability (0.9) to fail. For 10 runs this means a probabilty 0.9

If you want to nerd out on the subject here are some additional resources: