Source: https://guthlabs.ai/docs/instruments/hourly-rate-freelance-pricing-calculator/implementation/

instrument implementation / implementation-contract

# Hourly Rate / Freelance Pricing Calculator implementation

A source-bound implementation contract for Hourly Rate / Freelance Pricing 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**: t5-041

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-utilization case produces a division by zero and must be rejected. Additionally, tax_buffer_percent is an input without a defined role in the supplied formula, and project_rate_suggestion cannot be computed without project-duration inputs.

## 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": {
    "target_income": 60000,
    "overhead": 12000,
    "working_weeks": 48,
    "hours_per_week": 40,
    "utilization_pct": 60,
    "tax_buffer_pct": 25
  },
  "expected_outputs": {
    "billable_hours": 1152,
    "required_hourly_rate": 62.5,
    "day_rate": null,
    "project_rate_suggestion": null
  },
  "working": "billable_hours = 48 × 40 × (60 ÷ 100) = 48 × 40 × 0.60 = 1,152 hours.\\nrate = (60,000 + 12,000) ÷ 1,152 = 72,000 ÷ 1,152 = 62.50 per billable hour.\\ntax_buffer_pct = 25 is not used by the supplied formula. Day rate and project rate are undefined because no formulas are supplied."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/hourly-rate-freelance-pricing-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/hourly-rate-freelance-pricing-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/hourly-rate-freelance-pricing-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`