This calculator is arithmetic on a table, not a live mixer. Enter quantities from your own Fishing Master session. It will not click the shop.
Drop probability
Mythical skill roll chance
Chance of at least one Mythical skill in the number of spins you enter. The default 0.5% is the rate read from one Skill Master panel. Change it if your panel differs. This does not include the guaranteed Mythical at 500 spins.
Chance of at least one success = 1 − (1 − chance per attempt) raised to the number of attempts.
Default chance is the reported 0.5% Mythical rate. Pity at 500 spins is a separate rule and is not part of this calculation.
Material planner
Bamboo Fragment shortfall
The Bamboo Rod quest asks for 20 Bamboo Fragments from Jungle Island. Enter how many you already hold. The form does not know the drop amount per catch.
Required total = materials per upgrade × number of upgrades. Missing = max(required total − materials already owned, 0).
20 is the quest total from Giang Lao's offer. Drop rate per catch is not published, so owned is a count you type, not a prediction.