{
  "slug": "calorie-deficit",
  "title": "Calorie Deficit Calculator",
  "heading": "Calorie Deficit & Weight Loss Timeline Calculator",
  "category": "fitness-health",
  "url": "https://www.revenuelab.fyi/toolbox/calorie-deficit",
  "summary": "Daily calories and weeks to reach your goal weight.",
  "description": "A pound of fat stores roughly 3,500 calories, so a 500/day deficit averages about a pound a week. Deficits beyond 25% of maintenance accelerate muscle loss and adherence failure.",
  "formula": "Weeks = (Current − goal) × 3,500 ÷ (daily deficit × 7).",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=calorie-deficit",
  "inputs": [
    {
      "id": "maintenance",
      "label": "Maintenance calories (TDEE)",
      "kind": "number",
      "hint": null,
      "default": 2600,
      "unit": null,
      "min": 1000,
      "max": 6000
    },
    {
      "id": "weight",
      "label": "Current weight",
      "kind": "number",
      "hint": null,
      "default": 195,
      "unit": "lb",
      "min": 60,
      "max": 600
    },
    {
      "id": "goalWeight",
      "label": "Goal weight",
      "kind": "number",
      "hint": null,
      "default": 175,
      "unit": "lb",
      "min": 60,
      "max": 600
    },
    {
      "id": "deficit",
      "label": "Daily deficit",
      "kind": "number",
      "hint": null,
      "default": 500,
      "unit": "cal",
      "min": 100,
      "max": 1500
    }
  ],
  "outputs": [
    {
      "id": "calories",
      "label": "Daily calorie target",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "weeks",
      "label": "Weeks to goal",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "perWeek",
      "label": "Pounds lost per week",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "months",
      "label": "Months to goal",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "lbs",
      "label": "Pounds to lose",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "deficitPct",
      "label": "Deficit as % of maintenance",
      "format": "percent",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Maintenance calories (TDEE): 2600",
      "Current weight: 195 lb",
      "Goal weight: 175 lb",
      "Daily deficit: 500 cal"
    ],
    "outputs": [
      "Daily calorie target: 2,100",
      "Weeks to goal: 20",
      "Pounds lost per week: 1",
      "Months to goal: 4.6",
      "Pounds to lose: 20",
      "Deficit as % of maintenance: 19.2%"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter maintenance calories (tdee).",
      "Enter current weight (lb).",
      "Enter goal weight (lb).",
      "Enter daily deficit (cal).",
      "Read your daily calorie target on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "maintenance": 1550,
        "weight": 195,
        "goalWeight": 105,
        "deficit": 300
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "maintenance": 2600,
        "weight": 195,
        "goalWeight": 175,
        "deficit": 500
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "maintenance": 4150,
        "weight": 195,
        "goalWeight": 280,
        "deficit": 800
      }
    }
  ],
  "limitations": [
    "Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.",
    "Results do not account for medical conditions, medication, or pregnancy.",
    "Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it."
  ],
  "faq": [
    {
      "q": "How does the calorie deficit & weight loss timeline calculator work?",
      "a": "A pound of fat stores roughly 3,500 calories, so a 500/day deficit averages about a pound a week. Deficits beyond 25% of maintenance accelerate muscle loss and adherence failure. The underlying maths is: Weeks = (Current − goal) × 3,500 ÷ (daily deficit × 7)."
    },
    {
      "q": "What do I need to enter?",
      "a": "4 values: maintenance calories (tdee), current weight, goal weight, and daily deficit. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the daily calorie target result mean?",
      "a": "It is returned as a whole number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for anyone tracking a health or training target and wanting the standard formula applied correctly, without a signup or an app."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/protein-intake",
    "https://www.revenuelab.fyi/toolbox/running-pace",
    "https://www.revenuelab.fyi/toolbox/water-intake"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Calorie Deficit Calculator (https://www.revenuelab.fyi/toolbox/calorie-deficit)"
}