Loot Probability
Calculator
Results
- Probability of at least one drop
- 80.312559
- Probability of no drop
- 19.68744
- Expected number of drops
- 1.5
Gaming results
| Probability of at least one drop | 80.312559 |
| Probability of no drop | 19.68744 |
| Expected number of drops | 1.5 |
formula-map diagram
- Probability of at least one drop
- 80.312559
- Probability of no drop
- 19.68744
- Expected number of drops
- 1.5
Game math relationship
Formula
P(≥1 drop) = 1 − (1 − r)^n ; E[drops] = r × n= 80.312559565928
Note
This is a simplified model: it applies the standard probability or game-math formula to the numbers you entered. Real games add pity systems, drop-rate tiers, rounding, server-side variance and balance patches, so treat the result as an estimate rather than a guarantee.
More in Gaming and probability
See all →Frequently asked questions
What does this calculator find — the chance of getting the item at all, or a specific number of times?+
It typically calculates the probability of getting the item at least once across n attempts, though some versions also let you solve for the probability of exactly k successes using the binomial distribution.
How does the binomial distribution apply to loot drops?+
Each attempt is treated as an independent trial with the same success probability, which is exactly the setup the binomial distribution models — it lets you calculate the probability of any exact number of successes across a fixed number of attempts, not just "at least one."
Why does increasing attempts have diminishing returns on probability?+
Each additional attempt adds less to your cumulative probability than the one before, because you're multiplying the shrinking "still no success" probability by the same factor each time — going from 100 to 200 attempts helps far less than going from 0 to 100.
Does farming in a group change individual loot probability?+
It depends on the game's loot rules — some systems roll independently for each player (making group play strictly better for individual odds), while others split a shared drop pool, which can actually lower each player's personal chance compared to solo farming.
How do I use this to decide if farming a boss is worth my time?+
Calculate the expected number of attempts for the drop you want, multiply by the average time per attempt, and compare that time investment against the value of the item or an alternative way to obtain it.