What 10% actually means
Imagine 100 players each making ten independent attempts at a fixed 10% success rate. About 65 would get at least one success on average; about 35 would get none. Individual players can still be much luckier or unluckier.
For one attempt, the failure chance is 90%. For ten consecutive failures, multiply 0.9 by itself ten times. Subtract that result from 1:
P(at least one success) = 1 − (1 − p)n1 − 0.910 = 0.65132156…Here, p is the probability as a decimal and n is the number of attempts.
Budget is different from expected cost
Ten items at 400 tokens each require 4,000 tokens if you use them all. That buys ten attempts, not a successful mutation. If you stop after the first success, your actual spending may be lower than this full-attempt budget.
Under the same assumptions, the long-run average waiting time is 1 ÷ p. At 10%, that is ten attempts. An average is not a deadline: the chance of at least one success by attempt ten is still only 65.13%.
Does a failed roll improve the next one?
Only if the game has a mechanic that changes the odds. In an independent, fixed-rate model, the next attempt has the same chance after a failure. This calculator does not assume any pity system, luck boost or guaranteed mutation. If the rate changes between rolls, this simple model no longer describes those attempts.
Plan from the tokens you already have
Select “My token budget” to calculate whole attempts and leftover tokens. Read the worked budget guide for examples and limits.
When to use this tool
Use it to compare a budget you already have with a target probability. It does not recommend buying currency, predict the next result or calculate pet income. To check the item’s target and timing, read the Mutation Consumable guide.