Apparel SizeHat Size

Head Circumference (cm) to Inner Diameter (mm) Hat Size for Snug Fit

Snapshot

58 Head Circumference (cm) equals 185 Inner Diameter (mm).

  • Reference basis: This result uses the selected mm mapping as the profile basis.
  • Example: For 54 Head Circumference (cm), the mm mapping returns 172 Inner Diameter (mm) under the same fit assumptions.

Interactive conversion

Converter Calculator

Decimals: 1.5 or 1,5. Fractions: 1/2. Scientific notation: 1e3. Write 1000 without grouping separators.

185 Inner Diameter (mm) value

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API and AI agent access

Head Circumference (cm) to Inner Diameter (mm) Hat Size for Snug Fit. fit: snug-fit.

Machine-readable identifiers

Conversion family
hat-size
Source unit
circumference-centimeters
Target unit
diameter-millimeters
Fit
snug-fit

Use these identifiers in the API request. Sources and model limits also apply to software clients.

Example API request and response

POST /api/v1/convert

Request

{
  "family": "hat-size",
  "value": 58,
  "from": "circumference-centimeters",
  "to": "diameter-millimeters",
  "parameters": {
    "fit": "snug-fit"
  }
}

Essential response

{
  "ok": true,
  "conversion": {
    "family": "hat-size",
    "value": 58,
    "from": "circumference-centimeters",
    "to": "diameter-millimeters",
    "result": {
      "raw": 184.619733987,
      "display": "185"
    },
    "canonicalPath": "/apparel-size/hat-size/circumference-centimeters-to-diameter-millimeters-for-snug-fit/"
  }
}
API, OpenAPI and WebMCP documentation

Explanation

Head Circumference (cm) converts to Inner Diameter (mm) using head circumference in millimeters. Fit profile: Snug Fit.

Model estimate based on head circumference, not a fit guarantee. No manufacturer chart is established for this model; compare your measurement with the brand’s chart.

Method & Size Mapping

  • Model basis: output depends on the selected fit profile and follows the same fit mapping in both directions.
  • Profile reference: mm.
  • Consistency rule: calculator output and table values keep the same fit profile in both directions.

Common Conversion Values

Head Circumference (cm) valueInner Diameter (mm) value
54 172
56 178
58 185
60 191
62 197