Typing WPM / Accuracy Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Everyday & Life

Tranche

tranche-5

Evidence ID

t5-062

Ledger rows

1

No ledger note is attached.

Review findings

The arithmetic formulas are standard under the stated assumptions, but the instrument is not fully specified. Define the elapsed-time unit, character-counting convention, and exact meaning of error_count before implementation. The honest label should distinguish gross WPM from net WPM and state the 5-characters-per-word convention; labeling the result simply as words per minute could imply actual word counting.

Formula and scope findings

• The accuracy formula requires correct_chars, but the declared inputs provide only typed text and error count; it is ambiguous whether correct_chars should be calculated as total_chars − error_count.
• The meaning of error_count is undefined: character errors, incorrect keystrokes, uncorrected errors, and error events produce different accuracy and net-WPM results.
• The formulas require minutes, but the input is only described as elapsed time; the unit must be explicitly defined or converted.
• The formula is valid only when minutes > 0, characters_typed >= 0, and 0 <= error_count <= total_chars if errors represent incorrect characters.

Unit assumptions

• characters_typed and total_chars count all characters included by the product's convention, including or excluding spaces consistently.
• elapsed time is converted from seconds to minutes when necessary: minutes = elapsed_time_seconds / 60.
• The standard WPM convention is 5 characters per word.
• For the test vectors, error_count is assumed to mean incorrect character count, so correct_chars = characters_typed − error_count.
• WPM and error-rate calculations use decimal minutes; no rounding rule is specified for displayed outputs.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

Zero elapsed time makes both gross WPM and net WPM undefined, so the instrument must reject that input. The specification also does not state the elapsed-time unit and does not explicitly define correct_chars from error_count, creating additional ambiguity.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "characters_typed": 300,
    "elapsed_time_seconds": 120,
    "error_count": 15
  },
  "expected_outputs": {
    "gross_WPM": 30,
    "net_WPM": 22.5,
    "accuracy_percent": 95
  },
  "working": "minutes = 120 / 60 = 2; gross_WPM = (300 / 5) / 2 = 60 / 2 = 30; correct_chars = 300 − 15 = 285; accuracy = (285 / 300) × 100 = 0.95 × 100 = 95%; net_WPM = 30 − (15 / 2) = 30 − 7.5 = 22.5."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json