{
  "id": "calorie",
  "version": "fb42db2fd930",
  "status": "published",
  "name": "Calorie Calculator",
  "question": "How many calories do I need a day?",
  "summary": "Estimates the calories a day an adult needs to keep their weight (BMR × activity factor), and the daily targets to lose or gain 0.5 to 2 pounds a week.",
  "category": "health",
  "subcategory": "nutrition",
  "url": "https://www.acalculator.org/health/calorie-calculator",
  "markdown": "https://www.acalculator.org/health/calorie-calculator.md",
  "kind": "function",
  "method": "Calories to keep your weight = BMR × activity factor, with BMR from Mifflin-St Jeor (10 × kg + 6.25 × cm − 5 × age + 5, or − 161 for women) or the revised Harris-Benedict; each 500 calories a day less loses about 1 lb a week.",
  "assumptions": [
    "The formulas are for adults (Mifflin-St Jeor was fitted on people aged 19 to 78). They are not for children, pregnancy or breastfeeding.",
    "Activity factors: sedentary 1.2, light 1.375, moderate 1.55, very active 1.725, extra active 1.9.",
    "A pound of body weight is taken as 3,500 calories, so 500 fewer calories a day is about 1 lb a week. Real loss slows over time as your needs fall.",
    "Loss targets under 1,200 calories a day (women) or 1,500 (men) are left out, the low end of the diets in the 2013 AHA/ACC/TOS guideline.",
    "This is an estimate for planning, not medical advice."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "sex": {
        "title": "Sex",
        "description": "Sex at birth, which the body formulas use.",
        "type": "string",
        "enum": [
          "male",
          "female"
        ]
      },
      "age": {
        "title": "Age",
        "description": "Your age in whole years.",
        "type": "integer",
        "minimum": 18,
        "maximum": 100
      },
      "height": {
        "title": "Height",
        "description": "Your height without shoes.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.9,
        "maximum": 3
      },
      "weight": {
        "title": "Weight",
        "description": "Your body weight.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "minimum": 25,
        "maximum": 700
      },
      "activity": {
        "title": "Activity",
        "description": "How active you are in a usual week, which sets the multiplier on your BMR.",
        "type": "string",
        "enum": [
          "sedentary",
          "light",
          "moderate",
          "very",
          "extra"
        ]
      },
      "formula": {
        "title": "BMR formula",
        "description": "The equation for basal metabolic rate: Mifflin-St Jeor (1990) or the revised Harris-Benedict (1984).",
        "type": "string",
        "enum": [
          "mifflin",
          "harris"
        ]
      }
    }
  },
  "outputs": {
    "maintain": {
      "label": "Calories to keep your weight",
      "description": "Estimated calories a day to keep your current weight: BMR × activity factor.",
      "format": "number"
    },
    "mildLoss": {
      "label": "Lose 0.5 lb (0.23 kg) a week",
      "description": "Calories a day to lose about half a pound a week: 250 fewer than to keep your weight.",
      "format": "number"
    },
    "loss": {
      "label": "Lose 1 lb (0.45 kg) a week",
      "description": "Calories a day to lose about one pound a week: 500 fewer than to keep your weight.",
      "format": "number"
    },
    "fastLoss": {
      "label": "Lose 2 lb (0.91 kg) a week",
      "description": "Calories a day to lose about two pounds a week: 1,000 fewer than to keep your weight.",
      "format": "number"
    },
    "mildGain": {
      "label": "Gain 0.5 lb (0.23 kg) a week",
      "description": "Calories a day to gain about half a pound a week: 250 more than to keep your weight.",
      "format": "number"
    },
    "gain": {
      "label": "Gain 1 lb (0.45 kg) a week",
      "description": "Calories a day to gain about one pound a week: 500 more than to keep your weight.",
      "format": "number"
    },
    "bmr": {
      "label": "BMR (calories at complete rest)",
      "description": "Basal metabolic rate: the calories a day your body uses at complete rest.",
      "format": "number"
    },
    "limit": {
      "label": "Note",
      "description": "Which loss targets are left out because they fall below the lowest intake the guideline suggests.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "sex": "female",
      "age": 30,
      "height": 1.651,
      "weight": 68.0388555,
      "activity": "light",
      "formula": "mifflin"
    },
    "outputs": {
      "maintain": 1926.737388125,
      "mildLoss": 1676.737388125,
      "loss": 1426.737388125,
      "mildGain": 2176.737388125,
      "gain": 2426.737388125,
      "bmr": 1401.263555,
      "limit": "Losing 2 lb a week would mean eating under 1,200 calories a day, below the lowest diet the weight-loss guideline suggests."
    },
    "text": "You need about 1,927 calories a day to keep your current weight."
  },
  "examples": [
    {
      "given": {
        "sex": "female",
        "age": 30,
        "height": 1.651,
        "weight": 68.0388555,
        "activity": "light",
        "formula": "mifflin"
      },
      "expect": {
        "bmr": 1401.263555,
        "maintain": 1926.737388125,
        "mildLoss": 1676.737388125,
        "loss": 1426.737388125,
        "gain": 2426.737388125,
        "limit": "Losing 2 lb a week would mean eating under 1,200 calories a day, below the lowest diet the weight-loss guideline suggests."
      },
      "source": "Mifflin et al. 1990 and the 1.375 activity factor; hand calculation in content.mdx"
    },
    {
      "given": {
        "sex": "male",
        "age": 35,
        "height": 1.778,
        "weight": 81.6466266,
        "activity": "moderate",
        "formula": "mifflin"
      },
      "expect": {
        "bmr": 1757.716266,
        "maintain": 2724.4602123,
        "fastLoss": 1724.4602123,
        "mildGain": 2974.4602123
      },
      "source": "Mifflin et al. 1990 and the 1.55 activity factor; hand calculation in content.mdx"
    },
    {
      "given": {
        "sex": "female",
        "age": 40,
        "height": 1.65,
        "weight": 60,
        "activity": "sedentary",
        "formula": "harris"
      },
      "expect": {
        "bmr": 1340.383,
        "maintain": 1608.4596
      },
      "source": "Roza and Shizgal 1984 (revised Harris-Benedict) and the 1.2 activity factor; hand calculation in content.mdx"
    },
    {
      "given": {
        "sex": "female",
        "age": 60,
        "height": 1.55,
        "weight": 50,
        "activity": "sedentary",
        "formula": "mifflin"
      },
      "expect": {
        "maintain": 1209.3,
        "limit": "Losing 0.5 lb, 1 lb or 2 lb a week would mean eating under 1,200 calories a day, below the lowest diet the weight-loss guideline suggests."
      },
      "source": "Mifflin et al. 1990; AHA/ACC/TOS 2013 guideline (1,200 kcal a day for women); 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",
    "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 (2004), section 5.3.1, Classification of physical activity levels (PAL = TEE ÷ BMR). https://www.fao.org/4/y5686e/y5686e07.htm",
    "Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 1958;6(5):542-546. https://doi.org/10.1093/ajcn/6.5.542",
    "Jensen MD, Ryan DH, Apovian CM, et al. 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults. Circulation. 2014;129(25 Suppl 2):S102-S138. https://pmc.ncbi.nlm.nih.gov/articles/PMC5819889/",
    "Centers for Disease Control and Prevention. Steps for Losing Weight. https://www.cdc.gov/healthy-weight-growth/losing-weight/index.html"
  ],
  "related": [
    "tdee",
    "calorie-deficit",
    "macro",
    "bmi"
  ],
  "changelog": [
    {
      "date": "2026-09-28",
      "note": "Shorter activity labels so they fit the select at 375 px."
    }
  ]
}