Gacha Probability Calculator β Pull Odds, Pity & Cost
Calculate your real chance of pulling a character or item: probability of at least one hit in N pulls, pulls needed for 50/90/99% odds, expected hits, hard-pity guarantee and total cost.
π Runs entirely in your browser. Your input and output are never sent to a server or stored β fully private.
Each pull is independent: past misses do not make the next pull more likely β there is no "due" hit. Even after many pulls the chance can stay below 100% forever (only a hard pity guarantees it). P(at least one) = 1 β (1 β p)^N.
About this tool
How many pulls until the banner character is actually yours? Wondering beats knowing β so this calculator turns a gacha rate into hard numbers. Enter the drop rate and your planned number of pulls, and it shows the probability of at least one hit, the expected number of hits, and how many pulls you would need for a 50%, 90% or 99% chance. Add your game's pity or ceiling and it estimates the worst-case cost too. Works for any gacha, lootbox or drop-rate system, and every calculation runs locally in your browser β nothing about your spending habits goes anywhere.
Frequently asked questions
I have failed 80 pulls in a row β am I due for a hit soon?
Unfortunately no β unless your game has pity, each pull is independent, and the machine has no memory of your losing streak. A 1% banner is still exactly 1% on pull 81, no matter what came before. The feeling that a win is 'due' is the gambler's fallacy, and it is precisely how streaks lure people into overspending. What is true: across many pulls, the chance of at least one hit climbs β about 55% after 80 pulls at 1% β but it never reaches 100% without a pity system.
How does a pity or ceiling system change the math?
Pity puts a hard cap on your bad luck. Without it, probability only ever approaches 100%; with a ceiling of, say, 90 pulls, you are guaranteed the item by pull 90, so your worst-case cost becomes a fixed, budgetable number. Soft pity β where rates rise sharply near the ceiling, as in several popular gacha games β pulls the average cost well below the ceiling itself. This calculator shows both views: the pure probability curve and the maximum spend your pity implies. Always check your game's exact rules, since systems vary.
Is my pull data or budget information sent anywhere?
No. The rates, pull counts and costs you enter are processed entirely on your device using standard binomial probability β nothing is uploaded, stored or shared, and the page keeps working offline once loaded. A tip for accuracy: use the rate for the specific item you want, not the overall banner rate. If the 5-star rate is 0.6% but the featured character is only half of those, the number to enter is 0.3%. Rates are published in each game's in-game details screen.