This calculator is arithmetic on a table, not a live mixer. Enter quantities from your own Needle In A Haystack session. It will not click the shop.
Drop probability
What-if search checks
Tests the chance that at least one check succeeds. You type the percent and the number of checks. This is not the game's drop rate. The experience says the haystack has 5 million straws, and the Facility 09 badge describes a by-hand clear. Those are not a per-click percentage.
Chance of at least one success = 1 − (1 − chance per attempt) raised to the number of attempts.
The defaults of 1 percent and 100 checks are placeholders so the form is not silently using another game's rate. Replace both. Do not convert 5 million straws into a percent unless you have decided that each check is one equally likely straw.
Upgrade payback
Purchase payback
Estimates how many cycles of extra cash cover a price you enter. Catalogue pass prices can be used as the price. Straw value and skill-tree costs are not published, so the extra cash per cycle has to come from your session.
Payback cycles = upgrade cost ÷ extra profit per cycle, rounded up.
249 is the catalogue price of 2× HANDS, 2× CASH, and VENT IN YOUR POCKET. It is not a straw price. The extra-cash default of 1 is only a placeholder. Type the extra cash one cycle paid you and how many minutes that cycle took.