This calculator is arithmetic on a table, not a live mixer. Enter quantities from your own Survive a Million Monkeys session. It will not click the shop.
Material planner
Gems still needed
Enter the Gem price shown in the hub, how many of that purchase you want, and the Gems already on the account. The result is the shortfall. It does not read your Roblox inventory.
Required total = materials per upgrade × number of upgrades. Missing = max(required total − materials already owned, 0).
The demo price is the published 15,000 Gem Medic unlock. The demo balance is 13,000 Gems, which is the 12,000 Gems from 1MVISITS, SURVIVE, and MONKEYS plus the 1,000 Gem gift box, if every one of those claims works. Replace both numbers with the price and balance shown on your account. Per-level class and weapon upgrade prices were not published, so this form cannot price those steps.