{
  "id": "mid-parental-height",
  "version": "f38e5f128a3b",
  "status": "published",
  "name": "Mid-Parental Height Calculator",
  "question": "What is the mid-parental height?",
  "summary": "Works out a child’s mid-parental target height from both parents’ heights with Tanner’s method, (father + mother ± 13 cm) ÷ 2, and the ± 8.5 cm target range.",
  "category": "health",
  "subcategory": "body",
  "url": "https://www.acalculator.org/health/mid-parental-height-calculator",
  "markdown": "https://www.acalculator.org/health/mid-parental-height-calculator.md",
  "kind": "function",
  "method": "Mid-parental height = (father’s height + mother’s height + 13 cm) ÷ 2 for a boy, or − 13 cm for a girl; target range ± 8.5 cm.",
  "assumptions": [
    "Men are on average about 13 cm taller than women, so the parents’ average is moved 6.5 cm up for a boy and 6.5 cm down for a girl (Tanner 1970).",
    "The target range of 8.5 cm either side is Tanner’s, about the 3rd to 97th centile; later work widened it to about 9 cm for girls and 10 cm for boys.",
    "The parents are the biological parents, and the child grows in good health and nutrition.",
    "This is a rough guide for families, not a medical prediction. A pediatrician can use growth charts and bone age for more."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "sex": {
        "title": "Child’s sex",
        "description": "The child’s sex, which moves the target up or down by 6.5 cm.",
        "type": "string",
        "enum": [
          "male",
          "female"
        ]
      },
      "father": {
        "title": "Father’s height",
        "description": "The biological father’s adult height.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 1,
        "maximum": 2.5
      },
      "mother": {
        "title": "Mother’s height",
        "description": "The biological mother’s adult height.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 1,
        "maximum": 2.5
      }
    }
  },
  "outputs": {
    "target": {
      "label": "Mid-parental height",
      "description": "The target height: (father + mother + 13 cm) ÷ 2 for a boy, − 13 cm for a girl.",
      "format": "quantity",
      "unit": "in"
    },
    "feetInches": {
      "label": "In feet and inches, or metres",
      "description": "The mid-parental height in feet and inches (US) or in metres (Metric).",
      "format": "quantity",
      "unit": "ft-in"
    },
    "targetCm": {
      "label": "In centimetres",
      "description": "The mid-parental height in centimetres.",
      "format": "quantity",
      "unit": "cm"
    },
    "low": {
      "label": "Target range from",
      "description": "The low end of the target range: the mid-parental height − 8.5 cm.",
      "format": "quantity",
      "unit": "in"
    },
    "high": {
      "label": "Target range up to",
      "description": "The high end of the target range: the mid-parental height + 8.5 cm.",
      "format": "quantity",
      "unit": "in"
    },
    "average": {
      "label": "Parents’ average height",
      "description": "The plain average of the two heights, before the 6.5 cm sex adjustment.",
      "format": "quantity",
      "unit": "in"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "sex": "male",
      "father": 1.778,
      "mother": 1.6256
    },
    "outputs": {
      "target": 1.7668,
      "feetInches": 1.7668,
      "targetCm": 1.7668,
      "low": 1.6818,
      "high": 1.8518,
      "average": 1.7018
    },
    "text": "The mid-parental height is 69.6 in (5 ft 9.6 in), with a target range of 66.2 in to 72.9 in."
  },
  "examples": [
    {
      "given": {
        "sex": "male",
        "father": 1.778,
        "mother": 1.6256
      },
      "expect": {
        "target": 1.7668,
        "low": 1.6818,
        "high": 1.8518,
        "average": 1.7018
      },
      "source": "Tanner JM, Goldstein H, Whitehouse RH, Standards for children’s height at ages 2–9 years allowing for heights of parents, Arch Dis Child 1970;45:755–762, https://doi.org/10.1136/adc.45.244.755; Zeevi D et al., Accurate Prediction of Children’s Target Height from Their Mid-Parental Height, Children (Basel) 2024 (NIH PMC: Tanner’s ± 6.5 cm sex adjustment and ± 8.5 cm range), https://pmc.ncbi.nlm.nih.gov/articles/PMC11352326/, retrieved 2026-10-02; hand calculation in content.mdx: (177.8 + 162.56 + 13) ÷ 2 = 176.68 cm",
      "tolerance": 1e-12
    },
    {
      "given": {
        "sex": "female",
        "father": 1.778,
        "mother": 1.6256
      },
      "expect": {
        "target": 1.6368,
        "low": 1.5518,
        "high": 1.7218
      },
      "source": "Tanner JM, Goldstein H, Whitehouse RH, Standards for children’s height at ages 2–9 years allowing for heights of parents, Arch Dis Child 1970;45:755–762, https://doi.org/10.1136/adc.45.244.755; hand calculation in content.mdx: (177.8 + 162.56 − 13) ÷ 2 = 163.68 cm",
      "tolerance": 1e-12
    },
    {
      "given": {
        "sex": "female",
        "father": 1.8,
        "mother": 1.65
      },
      "expect": {
        "target": 1.66,
        "targetCm": 1.66,
        "average": 1.725
      },
      "source": "Tanner JM, Goldstein H, Whitehouse RH, Standards for children’s height at ages 2–9 years allowing for heights of parents, Arch Dis Child 1970;45:755–762, https://doi.org/10.1136/adc.45.244.755; hand calculation in content.mdx: (180 + 165 − 13) ÷ 2 = 166 cm",
      "tolerance": 1e-12
    }
  ],
  "sources": [
    "Tanner JM, Goldstein H, Whitehouse RH. Standards for children’s height at ages 2–9 years allowing for heights of parents. Arch Dis Child. 1970;45(244):755–762. https://doi.org/10.1136/adc.45.244.755",
    "Zeevi D, Ben Yehuda A, Nathan D, Zangen D, Kruglyak L. Accurate Prediction of Children’s Target Height from Their Mid-Parental Height. Children (Basel). 2024 (Tanner’s ± 6.5 cm sex adjustment and ± 8.5 cm range; later ± 9 cm for girls and ± 10 cm for boys), retrieved 2026-10-02. https://pmc.ncbi.nlm.nih.gov/articles/PMC11352326/",
    "Centers for Disease Control and Prevention. Growth charts, retrieved 2026-10-02. https://www.cdc.gov/growthcharts/"
  ],
  "related": [
    "height",
    "height-percentile",
    "growth-chart"
  ],
  "changelog": []
}