{
  "id": "bmr",
  "version": "708925acf36f",
  "status": "published",
  "name": "BMR Calculator",
  "question": "What is my BMR?",
  "summary": "Estimates basal metabolic rate (calories a day at rest) with the Mifflin-St Jeor, revised Harris-Benedict, or Katch-McArdle equation, and daily energy needs at three activity levels.",
  "category": "health",
  "subcategory": "body",
  "url": "https://www.acalculator.org/health/bmr-calculator",
  "markdown": "https://www.acalculator.org/health/bmr-calculator.md",
  "kind": "formulas",
  "method": "Mifflin-St Jeor: BMR = 10W + 6.25H − 5A + 5 (men) or − 161 (women). Harris-Benedict (Roza and Shizgal 1984): 88.362 + 13.397W + 4.799H − 5.677A (men), 447.593 + 9.247W + 3.098H − 4.330A (women). Katch-McArdle: 370 + 21.6 × W × (1 − body fat ÷ 100). W in kg, H in cm, A in years.",
  "assumptions": [
    "The equations estimate the energy used at complete rest for healthy adults; a measured value can differ.",
    "Katch-McArdle uses lean body mass (weight × (1 − body fat ÷ 100)), so it ignores sex, age, and height.",
    "Daily energy needs are BMR × the physical activity level (PAL) of the FAO/WHO/UNU (2004) examples: 1.53, 1.76, and 2.25."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "bodyWeight": {
        "title": "Weight",
        "description": "Your body weight.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "exclusiveMinimum": 0,
        "maximum": 700
      },
      "height": {
        "title": "Height",
        "description": "Your height without shoes. Katch-McArdle does not use it.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 3
      },
      "age": {
        "title": "Age",
        "description": "Your age in whole years. Katch-McArdle does not use it.",
        "type": "integer",
        "minimum": 1,
        "maximum": 120
      },
      "bodyFat": {
        "title": "Body fat",
        "description": "Your body fat as a percent of body weight. Only Katch-McArdle uses it.",
        "type": "number",
        "x-unit": "percent",
        "minimum": 0,
        "maximum": 70
      },
      "bmr": {
        "title": "BMR (calories a day)",
        "description": "Basal metabolic rate: kilocalories a day the body uses at complete rest.",
        "type": "number",
        "exclusiveMinimum": 0,
        "maximum": 10000
      },
      "sex": {
        "title": "Sex",
        "description": "Sex at birth. Mifflin-St Jeor and Harris-Benedict use it.",
        "type": "string",
        "enum": [
          "male",
          "female"
        ]
      },
      "formula": {
        "title": "Formula",
        "description": "The equation used to estimate BMR.",
        "type": "string",
        "enum": [
          "mifflin-st-jeor",
          "harris-benedict",
          "katch-mcardle"
        ]
      }
    }
  },
  "solve": {
    "fillAny": 4,
    "variables": [
      "bodyWeight",
      "height",
      "age",
      "bodyFat",
      "bmr"
    ],
    "inputsOnly": [
      "height",
      "age",
      "bodyFat"
    ]
  },
  "outputs": {
    "weight": {
      "label": "Weight",
      "description": "Your body weight.",
      "format": "quantity"
    },
    "height": {
      "label": "Height",
      "description": "Your height without shoes. Katch-McArdle does not use it.",
      "format": "quantity"
    },
    "age": {
      "label": "Age",
      "description": "Your age in whole years. Katch-McArdle does not use it.",
      "format": "integer"
    },
    "bodyFat": {
      "label": "Body fat",
      "description": "Your body fat as a percent of body weight. Only Katch-McArdle uses it.",
      "format": "percent"
    },
    "bmr": {
      "label": "Your BMR",
      "description": "Basal metabolic rate: kilocalories a day the body uses at complete rest.",
      "format": "number"
    },
    "sedentary": {
      "label": "Sedentary or light activity (PAL 1.53)",
      "description": "Daily energy need at physical activity level 1.53 (FAO/WHO/UNU sedentary example): BMR × 1.53.",
      "format": "number"
    },
    "active": {
      "label": "Active or moderately active (PAL 1.76)",
      "description": "Daily energy need at physical activity level 1.76 (FAO/WHO/UNU active example): BMR × 1.76.",
      "format": "number"
    },
    "vigorous": {
      "label": "Vigorously active (PAL 2.25)",
      "description": "Daily energy need at physical activity level 2.25 (FAO/WHO/UNU vigorous example): BMR × 2.25.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "sex": "male",
      "formula": "mifflin-st-jeor",
      "height": 1.778,
      "bodyWeight": 81.6466266,
      "age": 30,
      "bodyFat": 15
    },
    "outputs": {
      "bmr": 1782.716266,
      "sedentary": 2727.5558869799997,
      "active": 3137.58062816,
      "vigorous": 4011.1115984999997
    },
    "text": "With the Mifflin-St Jeor (1990) formula, your BMR is about 1,783 calories a day."
  },
  "examples": [
    {
      "given": {
        "bodyWeight": 81.6466266,
        "height": 1.778,
        "age": 30,
        "bodyFat": 15,
        "sex": "male",
        "formula": "mifflin-st-jeor"
      },
      "expect": {
        "bmr": 1782.716266,
        "active": 3137.58062816
      },
      "source": "Mifflin et al. (1990) men: 10 × 81.6466266 kg + 6.25 × 177.8 cm − 5 × 30 + 5 = 1,782.72 (hand calculation in content.mdx)"
    },
    {
      "given": {
        "bodyWeight": 60,
        "height": 1.65,
        "age": 40,
        "bodyFat": 30,
        "sex": "female",
        "formula": "mifflin-st-jeor"
      },
      "expect": {
        "bmr": 1270.25,
        "sedentary": 1943.4825
      },
      "source": "Mifflin et al. (1990) women: 10 × 60 + 6.25 × 165 − 5 × 40 − 161 = 1,270.25 (hand calculation in content.mdx)"
    },
    {
      "given": {
        "bodyWeight": 70,
        "height": 1.75,
        "age": 30,
        "bodyFat": 15,
        "sex": "male",
        "formula": "harris-benedict"
      },
      "expect": {
        "bmr": 1695.6670000000001
      },
      "source": "Revised Harris-Benedict (Roza and Shizgal 1984) men: 88.362 + 13.397 × 70 + 4.799 × 175 − 5.677 × 30 = 1,695.67 (hand calculation in content.mdx)"
    },
    {
      "given": {
        "bodyWeight": 55,
        "height": 1.6,
        "age": 25,
        "bodyFat": 25,
        "sex": "female",
        "formula": "harris-benedict"
      },
      "expect": {
        "bmr": 1343.608
      },
      "source": "Revised Harris-Benedict (Roza and Shizgal 1984) women: 447.593 + 9.247 × 55 + 3.098 × 160 − 4.330 × 25 = 1,343.61 (hand calculation in content.mdx)"
    },
    {
      "given": {
        "bodyWeight": 80,
        "height": 1.8,
        "age": 30,
        "bodyFat": 20,
        "sex": "male",
        "formula": "katch-mcardle"
      },
      "expect": {
        "bmr": 1752.4,
        "vigorous": 3942.9
      },
      "source": "Katch-McArdle: lean mass 80 × 0.8 = 64 kg; 370 + 21.6 × 64 = 1,752.4 (hand calculation in content.mdx)"
    },
    {
      "given": {
        "bmr": 1800,
        "height": 1.8,
        "age": 30,
        "bodyFat": 15,
        "sex": "male",
        "formula": "mifflin-st-jeor"
      },
      "expect": {
        "bodyWeight": 82
      },
      "source": "Mifflin-St Jeor solved for weight: (1,800 − 1,125 + 150 − 5) ÷ 10 = 82 kg (hand calculation in content.mdx)"
    }
  ],
  "sources": [
    "Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. https://doi.org/10.1093/ajcn/51.2.241",
    "Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. Am J Clin Nutr. 1984;40(1):168-182. https://doi.org/10.1093/ajcn/40.1.168",
    "Harris JA, Benedict FG. A biometric study of human basal metabolism. Proc Natl Acad Sci USA. 1918;4(12):370-373. https://doi.org/10.1073/pnas.4.12.370",
    "McArdle WD, Katch FI, Katch VL. Exercise Physiology: Nutrition, Energy, and Human Performance. Lippincott Williams & Wilkins (Katch-McArdle equation, 370 + 21.6 × lean body mass).",
    "Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775-789. https://doi.org/10.1016/j.jada.2005.02.005",
    "FAO/WHO/UNU. Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation, 2004, chapter 5 (physical activity levels). https://www.fao.org/4/y5686e/y5686e07.htm"
  ],
  "related": [],
  "changelog": [
    {
      "date": "2026-09-28",
      "note": "The Katch-McArdle option label no longer carries “(uses body fat)”, so the answer reads cleanly."
    }
  ]
}