Pricing/Discount & Markdown Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-270

Effect

Computation or source lookup only

Input and validation requirements

A zero list price produces undefined required discount and undefined effective discount because the formulas divide by list price. The instrument should reject the input or display an explicit undefined result.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "list_price": 100,
    "discount_percent": 20,
    "stacking": false,
    "target_price": 80
  },
  "expected_outputs": {
    "final_price": 80,
    "total_dollar_off": 20,
    "effective_discount_percent": 20,
    "required_discount_percent": 20
  },
  "working": "Sale price = 100 * (1 - 20/100) = 100 * 0.80 = 80. Total $ off = 100 - 80 = 20. Effective discount = (20/100) * 100% = 20%. Required discount to reach 80 = (1 - 80/100) * 100% = 20%."
}

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-tranche4/tranche4-results.json