Break-Even & Contribution Margin Dashboard mechanism

Model scope

The core formulas are standard under constant per-unit price and variable cost assumptions. The honest label "Educational estimate" is appropriate, but the product should explicitly state that results are not individualized financial, tax, legal, or investment advice. Exact review remains necessary for the undefined sensitivity-table specification and the missing behavior for zero or nonpositive contribution margins.

• CM=price−varCost is correct when price and variable cost are expressed in the same currency per unit.
• CM_ratio=CM/price is correct when price is nonzero; the specification does not define behavior when price=0.
• target_profit_units=(fixed+targetProfit)/CM is correct for continuous units under constant price and variable cost, but integer unit requirements should normally be rounded up with ceiling.
• The specification claims a sensitivity table but provides no sensitivity formulas, varied inputs, step sizes, or output definitions.
• The specification does not state the required feasibility constraint CM>0; CM=0 causes division by zero and CM<0 produces economically infeasible or misleading unit results.

Units and conventions

• price and variable cost must use the same currency and both must be amounts per unit sold.
• fixed costs and target profit must use the same currency as total contribution, not currency per unit.
• price must be nonzero for CM_ratio to be defined.
• The calculated target_profit_units is a continuous-unit result unless the implementation explicitly rounds up to a whole unit.
• No taxes, discounts, refunds, tiered costs, capacity limits, or changing prices/costs are included.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "price": 50,
    "variable_cost": 30,
    "fixed_costs": 10000,
    "target_profit": 5000,
    "currency": "USD",
    "unit_basis": "USD per unit"
  },
  "expected_outputs": {
    "CM": 20,
    "CM_ratio": 0.4,
    "units_for_target_profit": 750
  },
  "working": "CM = 50 − 30 = 20 USD/unit. CM ratio = 20 / 50 = 0.4 = 40%. Required contribution = 10,000 + 5,000 = 15,000 USD. Target-profit units = 15,000 / 20 = 750 units."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The specification permits inputs that produce undefined division, especially price = 0 and CM = 0, without stating validation behavior. It also does not define handling for nonpositive contribution margins, which can yield negative unit requirements for a positive target profit, or clarify whether target profit is signed.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json