Koshin StudioTools
Calculators
These calculators run only in your browser. The numbers you enter are not sent anywhere. Each one is checked against the results of a computer simulation of 200,000 players.
Each shows not only the average but also how long an unlucky player takes (the number of tries by which 90% and 99% of people succeed). Looking only at the average makes it easy to believe “it should hit by then.” If you are not sure which to use:
- You want every type (capsule toys, randomly packed collections) → the completion calculator.
- You want one specific item (a gacha with a fixed drop rate, with or without pity) → the drop rate and pity calculator.
- You want to know whether a booster box is priced above retail → the price per pack calculator.
- You enter several lottery sales (with known or estimated odds) → the lottery win chance calculator.
All of these are probabilities, not guarantees. Where the assumptions do not hold (odds that change mid-game, lotteries that forbid multiple entries), each page explains it under “when this calculation does not fit.”
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Gacha completion calculator
How many pulls, and how much money, to collect every type. The average, the pulls by which 90% of people finish, and whether a complete set is cheaper.
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Gacha drop rate and pity calculator
From the drop rate, how many pulls until you get it. Supports how many copies you want and a pity (guaranteed after N pulls).
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TCG booster box price per pack calculator
Turn a booster box or set price into a price per pack and compare it with the list price. Typical pack counts per box for each game, counted from 179 listings.
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Lottery win chance calculator
From the odds and the number of entries, the chance you win at least once. Works even when each entry has different odds.