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Calorie Deficit Calculator (Weight Loss Planner)

Calculate your daily calorie deficit and target intake to lose weight safely and effectively, with or without a known BMR.

If left empty, it will be calculated automatically based on your age, gender, height, and activity level. (auto-estimate below ...)
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    🔥 Overview: Plan Your Weight Loss With Precision

    The Calorie Deficit Calculator is a science-based tool designed to help you lose weight in a controlled, measurable way. Whether you're a fitness beginner, athlete, or nutrition coach, this tool helps determine:

    • ✅ Your total calorie deficit needed to reach your goal weight
    • ✅ Your daily calorie deficit based on your chosen timeframe
    • ✅ Your target daily calorie intake to maintain steady fat loss

    It supports both metric (kg/cm) and imperial (lb/inch) units and allows you to use your known Basal Metabolic Rate (BMR) or let the tool estimate it for you using the Mifflin-St Jeor equation.

    📐 Formula & Methodology

    The calorie deficit needed for weight loss is based on the energy content of fat:

    Fat Loss = Current Weight – Target Weight

Total Calorie Deficit:
- Metric: Fat Loss (kg) × 7,700 kcal
- Imperial: Fat Loss (lb) × 3,500 kcal

Duration (days) = Weeks × 7 or Months × 30

Daily Deficit = Total Deficit ÷ Duration

Target Intake = Daily Burn (BMR × Activity Level) – Daily Deficit

    If BMR is unknown: We use the Mifflin-St Jeor Equation to estimate it:

    BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age) + s
where s = +5 for males, –161 for females
→ Final BMR × Activity Level Multiplier (e.g., 1.55 for Moderate)

    🧮 Example Calculation

    Let’s say you weigh 80 kg and want to reduce to 70 kg in 2 months:

    • Fat Loss = 80 – 70 = 10 kg
    • Total Deficit = 10 × 7,700 = 77,000 kcal
    • Duration = 2 × 30 = 60 days
    • Daily Deficit = 77,000 ÷ 60 = 1,283 kcal/day
    • If your BMR = 2,200 kcal, target intake = 2,200 – 1,283 = ~917 kcal/day

    Note: This is an aggressive target—adjust based on your needs and safety guidelines.

    💡 Use Cases

    • 📉 Plan a calorie deficit for healthy, sustainable weight loss
    • 📊 Compare intake vs burn across various activity levels
    • 🧠 Use with macro calculators and TDEE estimators
    • 🧮 Calculate targets for clients, patients, or fitness programs
    • 📱 Optimize tracking with fitness apps like MyFitnessPal or Cronometer

    ❓ Frequently Asked Questions (FAQ)

    🧮 What is a calorie deficit?

    It’s when you consume fewer calories than your body burns, prompting fat loss to meet the energy gap.

    ⚖️ How many calories are in a kg or lb of fat?

    1 kg of fat ≈ 7,700 kcal; 1 lb of fat ≈ 3,500 kcal. These are general estimates used for weight loss planning.

    ⏱️ What is a safe rate of fat loss?

    Experts recommend losing 0.5–1 kg (1–2 lbs) per week for safety and sustainability.

    💡 What if I don’t know my BMR?

    Leave the BMR field blank. We'll estimate it using your age, sex, height, weight, and activity level.

    🔢 What activity level should I choose?

    Pick the one that reflects your lifestyle: Sedentary (no exercise), Light (1–3 days/week), Moderate (3–5 days), Very Active (daily intense activity).

    📏 Can I switch between kg/lb?

    Yes. Use the unit selector at the top. The tool instantly converts based on your selection.

    📆 Can I set a goal over months?

    Yes. Choose “months” and enter the number. The tool will convert it into days automatically for accurate planning.

    📱 Is this mobile-friendly?

    Absolutely! The calculator works on all screen sizes—desktop, tablet, and smartphone.

    🧾 Can I print or share my results?

    Yes! Use the built-in Copy or Print buttons to save or share your plan.

    🔁 Does clearing reset all results?

    Yes. Clicking “Clear” will reset the entire form and hide previous outputs.