Each decryptor option is costed as a whole batch, then divided by the units the batch makes. The cheapest per-unit total wins, and its margin is worked out against what the batch sells for (section 7).

1. Success chance of one invention attempt

chance = min(1, base × (1 + (science₁ + science₂) / 30 + encryption / 40) × (1 + decryptor% / 100))

base is the item's own invention chance from the game data; the skills are levels 0–5; decryptor% is the modifier in the table below (omitted without a decryptor).

2. What each invented copy is

runs per copy = max(1, base runs + decryptor runs)     base runs = 1 for ships and rigs, 10 for everything else
ME of copy     = 2 + decryptor ME
TE of copy     = 4 + decryptor TE

3. How many attempts the batch needs

copies needed k = ceil(batch runs / runs per copy)
attempts n     = the smallest n for which P(at least k successes in n attempts) ≥ 90%
P(X ≥ k)       = Σ for i = k..n of  C(n, i) × chance^i × (1 − chance)^(n − i)

Every attempt costs the same whether it succeeds or not, so you pay for n attempts, not for the k that work.

4. Cost of the invention

EIV             = Σ (the invented item's manufacturing materials at ME 0 × CCP adjusted price)
job cost        = floor(EIV × system cost index × (1 − structure and rig reduction))
                + floor(EIV × (facility tax% + SCC surcharge%) / 100)
cost per attempt = datacores + decryptor + job cost
invention total  = n × cost per attempt

Datacores and the decryptor are bought at the market price shown under "Variables used". The job cost uses CCP's adjusted prices instead, so it does not move with the market.

5. Cost of building the invented item

ME%             = 1 − (1 − structure role) × (1 − rig × security) × (1 − copy ME / 100)
material needed = max(runs, ceil(round(runs × base quantity × (1 − ME%), 2)))   for each material
build total     = Σ (material needed × price) + job installation fees for the whole build chain

A higher copy ME needs fewer materials, which is why a decryptor that adds ME can pay for itself on an expensive item.

6. The comparison

overall total = invention total + build total
per unit      = overall total / (runs × units per run)
price paid    = market price × (1 + brokerage% / 100)   when buying via buy orders;  market price when buying from sell orders

Brokerage is charged on placing your own buy order, so it is added to every purchased price (datacores, decryptor, materials) when the buy basis is Buy orders, and not at all when you buy from sell orders. Job installation fees are paid to the game, not bought, so it never applies to them.

7. Sale value and margin

gross sale = units × the Jita price on the sell basis chosen on the Pricing card
net sale   = gross × (1 − sales tax%) − gross × brokerage%      (brokerage only when selling via sell orders)
margin     = net sale − overall total
margin %   = margin / net sale
sales tax% = 7.5 × (1 − 0.11 × Accounting)         brokerage% = 3 − 0.3 × Broker Relations − 0.03 × faction standing − 0.02 × corp standing

The same item sells for the same price whichever decryptor made it, so the margin column puts the options in the same order as the cost column. What it adds is whether the best option makes money at all, and how much.

Decryptor modifiers

Worked example

Calculate an item above to see its winning option worked through step by step.