Source: https://guthlabs.ai/docs/instruments/work-hours-timesheet-calculator/implementation/

instrument implementation / implementation-contract

# Work Hours / Timesheet Calculator implementation

A source-bound implementation contract for Work Hours / Timesheet 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**: t5-029

**Effect**: Computation or source lookup only

## Input and validation requirements

A missing clock-out produces an undefined duration unless the calculator validates and rejects the input. Overnight clock pairs without dates are also convention-ambiguous and can produce a negative duration if same-day subtraction is applied.

## 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": {
    "shifts": [
      {
        "clock_in": "2025-01-06T09:00",
        "clock_out": "2025-01-06T17:00",
        "unpaid_break_minutes": 30
      },
      {
        "clock_in": "2025-01-07T09:00",
        "clock_out": "2025-01-07T17:00",
        "unpaid_break_minutes": 30
      },
      {
        "clock_in": "2025-01-08T09:00",
        "clock_out": "2025-01-08T17:00",
        "unpaid_break_minutes": 30
      },
      {
        "clock_in": "2025-01-09T09:00",
        "clock_out": "2025-01-09T17:00",
        "unpaid_break_minutes": 30
      },
      {
        "clock_in": "2025-01-10T09:00",
        "clock_out": "2025-01-10T17:00",
        "unpaid_break_minutes": 30
      }
    ],
    "overtime_threshold_hours": 40
  },
  "expected_outputs": {
    "total_hours": 37.5,
    "regular_hours": 37.5,
    "overtime_hours": 0
  },
  "working": "Each shift: 17:00 − 09:00 = 8 hours gross. Each break: 30 ÷ 60 = 0.5 hours. Each shift net: 8 − 0.5 = 7.5 hours. Weekly total: 5 × 7.5 = 37.5 hours. Overtime: max(0, 37.5 − 40) = max(0, −2.5) = 0 hours. Regular: 37.5 − 0 = 37.5 hours."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/work-hours-timesheet-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/work-hours-timesheet-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/work-hours-timesheet-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`