This calculator is arithmetic on a table, not a live mixer. Enter quantities from your own Angry Birds Tower Defense session. It will not click the shop.
Drop probability
Slingshot spin odds
Estimate the chance of at least one Red Slingshot (or any later roulette prize) if every spin is an independent roll at the chance you type. The 5 percent and 100-Feather price are launch-window reports, not a permanent rate table.
Chance of at least one success = 1 − (1 − chance per attempt) raised to the number of attempts.
Defaults match the reported Angry Birds Red Slingshot roulette: about 5 percent at 100 Feathers, with a stated stock of 3,000. The like-reward code grants 50 Feathers, which is short of one reported spin. Replace both inputs with the numbers on the live wheel. Each spin is treated as an independent roll. This does not read your inventory or guarantee a limited.
