Source: https://guthlabs.ai/docs/instruments/pace-split-calculator/implementation/

instrument implementation / implementation-contract

# Pace / Split Calculator implementation

A source-bound implementation contract for Pace / Split 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**: t4-199

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-speed case produces division by zero and undefined time, pace, and splits. Negative-distance handling is also convention-sensitive, and the unit-mode branch can produce 40 minutes or 64.37376 minutes from the same numerical pace and distance unless units are enforced.

## 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": {
    "distance": 5,
    "distance_unit": "mi",
    "time": 40,
    "time_unit": "min",
    "interval_distances": [
      1,
      1,
      1,
      1,
      1
    ],
    "interval_unit": "mi"
  },
  "expected_outputs": {
    "pace": 8,
    "pace_unit": "min/mi",
    "speed": 7.5,
    "speed_unit": "mph",
    "split_times": [
      8,
      8,
      8,
      8,
      8
    ],
    "split_time_unit": "min",
    "total_split_time": 40
  },
  "working": "pace = time ÷ distance = 40 min ÷ 5 mi = 8 min/mi. speed = distance ÷ time = 5 mi ÷ (40 min ÷ 60 min/h) = 5 ÷ (2/3) = 7.5 mi/h. Each split = pace × interval distance = 8 min/mi × 1 mi = 8 min. Five splits total = 8 + 8 + 8 + 8 + 8 = 40 min."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/pace-split-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/pace-split-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/pace-split-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-tranche4/tranche4-results.json`