{
  "id": "biological-age",
  "version": "879de34c4c36",
  "status": "published",
  "name": "Biological Age Calculator",
  "question": "What is my biological age?",
  "summary": "Estimates your biological age (phenotypic age, PhenoAge) from nine routine blood test results and your age with the Levine 2018 formula, and how far it is from your age in years.",
  "category": "health",
  "subcategory": "body",
  "url": "https://www.acalculator.org/health/biological-age-calculator",
  "markdown": "https://www.acalculator.org/health/biological-age-calculator.md",
  "kind": "function",
  "method": "xb = −19.907 − 0.0336 × albumin + 0.0095 × creatinine + 0.1953 × glucose + 0.0954 × ln(CRP) − 0.0120 × lymphocyte % + 0.0268 × MCV + 0.3306 × RDW + 0.00188 × ALP + 0.0554 × WBC + 0.0804 × age; M = 1 − exp(−1.51714 × e^xb ÷ 0.0076927); PhenoAge = 141.50225 + ln(−0.00553 × ln(1 − M)) ÷ 0.090165.",
  "assumptions": [
    "Units in the formula: albumin g/L, creatinine µmol/L, glucose mmol/L, CRP mg/dL (the typed mg/L ÷ 10), lymphocytes %, MCV fL, RDW %, ALP U/L, WBC 1000 cells/µL.",
    "US units convert as albumin g/dL × 10, creatinine mg/dL × 88.4 (KDIGO), glucose mg/dL ÷ 18.016.",
    "The formula was trained on US adults (NHANES III) to predict 10-year mortality; it is a research estimate, not a diagnosis."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "age": {
        "title": "Age (years)",
        "description": "Your age in years on the day of the blood test.",
        "type": "number",
        "minimum": 18,
        "maximum": 100
      },
      "units": {
        "title": "Lab units",
        "description": "US units (albumin g/dL, creatinine and glucose mg/dL) or SI units (g/L, µmol/L, mmol/L).",
        "type": "string",
        "enum": [
          "us",
          "si"
        ]
      },
      "alb": {
        "title": "Albumin (g/dL)",
        "description": "Serum albumin in g/dL.",
        "type": "number",
        "minimum": 1,
        "maximum": 7
      },
      "cr": {
        "title": "Creatinine (mg/dL)",
        "description": "Serum creatinine in mg/dL.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 15
      },
      "glu": {
        "title": "Glucose (mg/dL)",
        "description": "Fasting serum glucose in mg/dL.",
        "type": "number",
        "minimum": 20,
        "maximum": 600
      },
      "albSi": {
        "title": "Albumin (g/L)",
        "description": "Serum albumin in g/L.",
        "type": "number",
        "minimum": 10,
        "maximum": 70
      },
      "crSi": {
        "title": "Creatinine (µmol/L)",
        "description": "Serum creatinine in µmol/L.",
        "type": "number",
        "minimum": 9,
        "maximum": 1330
      },
      "gluSi": {
        "title": "Glucose (mmol/L)",
        "description": "Fasting serum glucose in mmol/L.",
        "type": "number",
        "minimum": 1.1,
        "maximum": 33.3
      },
      "crp": {
        "title": "C-reactive protein (mg/L)",
        "description": "C-reactive protein (CRP or hs-CRP) in mg/L.",
        "type": "number",
        "minimum": 0.01,
        "maximum": 300
      },
      "lym": {
        "title": "Lymphocytes (%)",
        "description": "Lymphocytes as a percent of white blood cells.",
        "type": "number",
        "minimum": 1,
        "maximum": 90
      },
      "mcv": {
        "title": "Mean cell volume (fL)",
        "description": "Mean corpuscular volume (MCV) in femtolitres.",
        "type": "number",
        "minimum": 50,
        "maximum": 130
      },
      "rdw": {
        "title": "Red cell distribution width (%)",
        "description": "RDW in percent.",
        "type": "number",
        "minimum": 8,
        "maximum": 30
      },
      "alp": {
        "title": "Alkaline phosphatase (U/L)",
        "description": "Alkaline phosphatase (ALP) in units per litre.",
        "type": "number",
        "minimum": 10,
        "maximum": 1000
      },
      "wbc": {
        "title": "White blood cells (×1000/µL)",
        "description": "White blood cell count in thousands per microlitre.",
        "type": "number",
        "minimum": 0.5,
        "maximum": 100
      }
    }
  },
  "outputs": {
    "phenoAge": {
      "label": "Biological age (PhenoAge)",
      "description": "141.50225 + ln(−0.00553 × ln(1 − M)) ÷ 0.090165.",
      "format": "number"
    },
    "gap": {
      "label": "Difference from your age (years)",
      "description": "PhenoAge − age: negative means younger than your age.",
      "format": "number"
    },
    "mortality": {
      "label": "10-year mortality score",
      "description": "M, the model’s 10-year chance of death, in percent.",
      "format": "percent"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "age": 45,
      "units": "us",
      "alb": 4.5,
      "cr": 0.9,
      "glu": 90,
      "albSi": 45,
      "crSi": 80,
      "gluSi": 5,
      "crp": 1,
      "lym": 30,
      "mcv": 90,
      "rdw": 13,
      "alp": 70,
      "wbc": 6
    },
    "outputs": {
      "phenoAge": 37.374585438633446,
      "gap": -7.625414561366554,
      "mortality": 1.5015704411112423
    },
    "text": "Your biological age (PhenoAge) is 37.4 years."
  },
  "examples": [
    {
      "given": {
        "age": 45,
        "units": "us",
        "alb": 4.5,
        "cr": 0.9,
        "glu": 90,
        "crp": 1,
        "lym": 30,
        "mcv": 90,
        "rdw": 13,
        "alp": 70,
        "wbc": 6
      },
      "expect": {
        "phenoAge": 37.374585438633474,
        "gap": -7.625414561366526,
        "mortality": 1.501570441111244
      },
      "source": "Levine ME and others, An epigenetic biomarker of aging for lifespan and healthspan, Aging 2018;10:573, Table 1 (phenotypic age weights), https://pmc.ncbi.nlm.nih.gov/articles/PMC5940111/; The full PhenoAge formula (intercept −19.907, 1.51714, 0.0076927, 141.50225, 0.00553, 0.090165) as printed in https://pmc.ncbi.nlm.nih.gov/articles/PMC12172999/ (retrieved 2026-10-05); Python 3 check in content.mdx: xb = −9.4754, PhenoAge 37.37",
      "tolerance": 1e-9
    },
    {
      "given": {
        "age": 60,
        "units": "si",
        "albSi": 38,
        "crSi": 110,
        "gluSi": 6.1,
        "crp": 5,
        "lym": 22,
        "mcv": 95,
        "rdw": 15,
        "alp": 95,
        "wbc": 8
      },
      "expect": {
        "phenoAge": 72.29520437032392,
        "gap": 12.295204370323916,
        "mortality": 29.712566143472696
      },
      "source": "Levine ME and others, An epigenetic biomarker of aging for lifespan and healthspan, Aging 2018;10:573, Table 1 (phenotypic age weights), https://pmc.ncbi.nlm.nih.gov/articles/PMC5940111/; The full PhenoAge formula (intercept −19.907, 1.51714, 0.0076927, 141.50225, 0.00553, 0.090165) as printed in https://pmc.ncbi.nlm.nih.gov/articles/PMC12172999/ (retrieved 2026-10-05); Python 3 check in content.mdx: xb = −6.3268, PhenoAge 72.30",
      "tolerance": 1e-9
    },
    {
      "given": {
        "age": 30,
        "units": "us",
        "alb": 4.8,
        "cr": 0.8,
        "glu": 85,
        "crp": 0.3,
        "lym": 35,
        "mcv": 88,
        "rdw": 12,
        "alp": 60,
        "wbc": 5
      },
      "expect": {
        "phenoAge": 14.325277767845463,
        "gap": -15.674722232154537
      },
      "source": "Levine ME and others, An epigenetic biomarker of aging for lifespan and healthspan, Aging 2018;10:573, Table 1 (phenotypic age weights), https://pmc.ncbi.nlm.nih.gov/articles/PMC5940111/; The full PhenoAge formula (intercept −19.907, 1.51714, 0.0076927, 141.50225, 0.00553, 0.090165) as printed in https://pmc.ncbi.nlm.nih.gov/articles/PMC12172999/ (retrieved 2026-10-05); Python 3 check in content.mdx: xb = −11.5537, PhenoAge 14.33",
      "tolerance": 1e-9
    }
  ],
  "sources": [
    "Levine ME, Lu AT, Quach A, and others. An epigenetic biomarker of aging for lifespan and healthspan. Aging (Albany NY). 2018;10(4):573-591, Table 1, retrieved 2026-10-05. https://pmc.ncbi.nlm.nih.gov/articles/PMC5940111/",
    "The full PhenoAge formula (intercept and constants) as printed in a 2025 open-access study, retrieved 2026-10-05. https://pmc.ncbi.nlm.nih.gov/articles/PMC12172999/",
    "KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (1 mg/dL creatinine = 88.4 µmol/L). https://kdigo.org/guidelines/ckd-evaluation-and-management/",
    "Meidenbauer JJ, Mukherjee P, Seyfried TN. Nutrition & Metabolism. 2015;12:12 (glucose mg/dL ÷ 18.016 = mmol/L), retrieved 2026-10-05. https://pmc.ncbi.nlm.nih.gov/articles/PMC4367849/"
  ],
  "related": [
    "life-expectancy",
    "heart-age"
  ],
  "changelog": []
}