Source: https://guthlabs.ai/docs/instruments/mulch-soil-gravel-volume-calculator/implementation/

instrument implementation / implementation-contract

# Mulch/Soil/Gravel Volume Calculator implementation

A source-bound implementation contract for Mulch/Soil/Gravel Volume Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t5-129

**Effect**: Computation or source lookup only

## Input and validation requirements

A zero bag volume causes division by zero and an undefined bag count. Negative depth is also not guarded by the stated arithmetic and can produce negative volume and negative bag counts instead of a validation error.

## 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": {
    "area_ft2": 120,
    "depth_in": 3,
    "bag_volume_ft3": 2
  },
  "expected_outputs": {
    "volume_ft3": 30,
    "cubic_yards": 1.1111111111,
    "bags": 15
  },
  "working": "volume_ft3 = 120 × 3 ÷ 12 = 360 ÷ 12 = 30 ft³; cubic_yards = 30 ÷ 27 = 1.1111111111 yd³; bags = ceil(30 ÷ 2) = ceil(15) = 15 bags."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/mulch-soil-gravel-volume-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/mulch-soil-gravel-volume-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/mulch-soil-gravel-volume-calculator/qualification/>)

## 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`