Every recommendation is traceable to the math.
The tool is a pre-screening and financial-modeling aid. It does not authenticate a card, issue a grade, appraise market value or provide investment advice.
Money strategy
All money is stored as integer cents. Percentages and grade probabilities are integer basis points, where 10,000 equals 100%. Percentage fees round once to the nearest cent.
Sale proceeds
fee base = sale price + applicable buyer shipping + applicable handling + applicable sales tax
marketplace fee = percentage fee + per-order fee + promoted fee + other marketplace costs
net proceeds = sale price + buyer shipping + handling − marketplace fee − seller shipping
Raw and graded profit
raw profit = raw net proceeds − acquisition cost
outcome profit = graded net proceeds − acquisition cost − allocated grading costs
expected graded profit = Σ(outcome profit × outcome probability)
incremental expected value = expected graded profit − raw profit
The break-even sale price is found with an integer-cents binary search against the complete marketplace fee function. The break-even grade is the lowest-price modeled outcome with nonnegative profit; labels never control the calculation.
Total profit versus from today forward
Total-profit view includes acquisition cost. When a card is already owned, from-today-forward view treats that purchase as sunk for displayed profit. The acquisition cost remains visible, and the raw-versus-grade incremental comparison remains mathematically consistent.
Recommendation thresholds
A strong candidate currently requires at least $50 of incremental expected value, at least 80% input completeness, non-low probability confidence and a loss probability inside the selected risk tolerance. A potential candidate requires at least $20 and a modestly wider loss band. Negative incremental value favors the raw-sale scenario or more research. These thresholds are site-defined, configurable and not industry standards.
Probability and uncertainty
Outcome probabilities must total exactly 100.00%. Preset controls are clearly labeled editable examples. Sensitivity rows lower top-grade probability, sale values, fee assumptions and grading costs so the recommendation is not driven by the best case.
Limits
- Market values are user-entered and may be wrong or stale.
- Centering, photos and checklists cannot reproduce a grader’s complete process.
- Turnaround estimates and grader fees can change quickly.
- Taxes, shipping and marketplace fees vary by seller and transaction.