{
  "id": "calorie-deficit",
  "version": "a5f66ef251ee",
  "status": "published",
  "name": "Calorie Deficit Calculator",
  "question": "What is my calorie deficit?",
  "summary": "Works out the daily calorie deficit and intake to lose a chosen weight each week: TDEE (BMR × activity factor) minus the rate × 3,500 calories per pound ÷ 7.",
  "category": "health",
  "subcategory": "nutrition",
  "url": "https://www.acalculator.org/health/calorie-deficit-calculator",
  "markdown": "https://www.acalculator.org/health/calorie-deficit-calculator.md",
  "kind": "function",
  "method": "Daily target = TDEE − weekly loss (lb) × 3,500 ÷ 7, with TDEE = BMR × activity factor and BMR from Mifflin-St Jeor or the revised Harris-Benedict.",
  "assumptions": [
    "A pound of body weight is taken as 3,500 calories (7,716 calories a kilogram). Real loss slows over time as your needs fall.",
    "TDEE is worked out at your current weight. Enter your new weight every few weeks.",
    "Activity factors: sedentary 1.2, light 1.375, moderate 1.55, very active 1.725, extra active 1.9.",
    "A target under 1,200 calories a day (women) or 1,500 (men) is shown with a warning: 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"
        ]
      },
      "rate": {
        "title": "Weight to lose each week",
        "description": "How much weight you want to lose each week.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "exclusiveMinimum": 0,
        "maximum": 1
      }
    }
  },
  "outputs": {
    "target": {
      "label": "Eat this many calories a day",
      "description": "Daily calories to lose the chosen weight each week: TDEE − daily deficit.",
      "format": "number"
    },
    "deficit": {
      "label": "Daily calorie deficit",
      "description": "Calories a day under your TDEE: weekly loss in lb × 3,500 ÷ 7.",
      "format": "number"
    },
    "tdee": {
      "label": "Calories to keep your weight (TDEE)",
      "description": "Total daily energy expenditure: BMR × activity factor.",
      "format": "number"
    },
    "share": {
      "label": "Deficit as a share of TDEE",
      "description": "The daily deficit as a percentage of TDEE.",
      "format": "percent"
    },
    "limit": {
      "label": "Note",
      "description": "A warning when the daily target is below the lowest intake the weight-loss guideline suggests.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "sex": "female",
      "age": 30,
      "height": 1.651,
      "weight": 68.0388555,
      "activity": "light",
      "formula": "mifflin",
      "rate": 0.45359237
    },
    "outputs": {
      "target": 1426.737388125,
      "deficit": 500,
      "tdee": 1926.737388125,
      "share": 25.950604533946052
    },
    "text": "Eat about 1,427 calories a day for your weekly goal: a deficit of 500 from your 1,927."
  },
  "examples": [
    {
      "given": {
        "sex": "female",
        "age": 30,
        "height": 1.651,
        "weight": 68.0388555,
        "activity": "light",
        "formula": "mifflin",
        "rate": 0.45359237
      },
      "expect": {
        "deficit": 500,
        "target": 1426.737388125,
        "tdee": 1926.737388125,
        "share": 25.950604533946052
      },
      "source": "Mifflin et al. 1990; 3,500 kcal per lb (Wishnofsky 1958); hand calculation in content.mdx"
    },
    {
      "given": {
        "sex": "male",
        "age": 45,
        "height": 1.8,
        "weight": 100,
        "activity": "moderate",
        "formula": "mifflin",
        "rate": 0.5
      },
      "expect": {
        "tdee": 2952.75,
        "deficit": 551.155655462194,
        "target": 2401.594344537806,
        "share": 18.665842196670695
      },
      "source": "Mifflin et al. 1990; 3,500 kcal per lb = 7,716.2 kcal per kg; hand calculation in content.mdx"
    },
    {
      "given": {
        "sex": "female",
        "age": 50,
        "height": 1.6,
        "weight": 70,
        "activity": "sedentary",
        "formula": "mifflin",
        "rate": 0.90718474
      },
      "expect": {
        "tdee": 1546.8,
        "deficit": 1000,
        "target": 546.8,
        "limit": "This is under 1,200 calories a day, below the lowest diet the weight-loss guideline suggests. Choose a slower rate or ask a doctor."
      },
      "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",
    "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",
    "Thomas DM, et al. Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule. Int J Obes. 2013;37(12):1611-1613. https://doi.org/10.1038/ijo.2013.51",
    "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": [
    "calorie",
    "tdee",
    "weight-loss",
    "macro"
  ],
  "changelog": [
    {
      "date": "2026-09-28",
      "note": "The share of TDEE is a whole percent; shorter activity labels."
    }
  ]
}