# Dropchance calculator

Simple loot drop chance calculator for Warframe or other video games. Warframe drop table can found here.

## runs

• 90% probability
• to succeed at least once
• runs back to back
• equal drop chance per run

## runs

• 99% probability
• to succeed at least once
• runs back to back
• equal drop chance per run

## % per run

• probability to get item per run
• 10 runs, % probability
• 20 runs, % probability
• 30 runs, % probability
• to succeed at least once

## Do not misunderstand drop chance

One of the most common misconceptions about drop chance is taking the percentage for granted:

• A 10% drop chance does not mean every 10th repetition.
• A 10% drop chance does not mean 10 of 100 tries is a success.
• A 10% drop chance only means that over a large enough sample size or number of tries – tens of thousands – roughly 10% of those tries will lead to success.

And because randomness is involved it is possible that with a 10% drop chance you fail 900 times before you succeed the next 100 times. That is the beauty of randomness.

### Math used

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.

This means for 10 consecutive runs the probality to fail equals 0.9^10 = 0.3486784401

Rounded to two decimal places we now have a probality to fail at 0.35 or 35%.

And this again means 65% chance of succeeding (at least once) in 10 runs when having a drop chance of 10%.

### Indepth article about drop chance and RNG

If you are interested to dig a bit deeper and learn more about drop chance and RNG in general there is a detailled article here on xplainthegame: RNG and drop chance in video games with focus on Warframe