Calorie Deficit Calculator

Tip: 10–25% is a common range for sustainable fat loss.
Enter to estimate time-to-goal.
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About Calorie Deficit Calculator

Our Calorie Deficit Calculator estimates your maintenance calories (TDEE) from age, sex, height, weight, and activity (using the Mifflin–St Jeor equation), then creates a daily calorie target for fat loss by applying a percent deficit or a custom kcal reduction. It’s a fast way to answer “How many calories should I eat to lose weight?”

Start by finding your TDEE (maintenance calories) and choose a moderate deficit (often 10–25%) to aim for a sustainable rate of loss (e.g., ~0.25–1.0 kg/week depending on body size and activity). The tool also supports metric & US units (kg/lb, cm/in, ft+in) and an optional goal weight to estimate time to goal.

How to use this Calorie Deficit Calculator

  1. Enter your age, sex, height, weight and activity level to calculate TDEE.
  2. Select a calorie deficit (Percent or Custom kcal) to get your daily calorie target for weight loss.
  3. (Optional) Add a goal weight to get a rough time-to-goal estimate.

Why use a moderate deficit?

  • Adherence: A 10–20% deficit is easier to sustain than aggressive cuts.
  • Performance: Training, recovery, and protein intake (see Protein Intake Calculator) help preserve lean mass.
  • Reality check: Trends matter—track 2–3 weeks and adjust ±100–200 kcal if progress stalls.

FAQ

  • How big should my calorie deficit be?
    Many people start with a 10–20% deficit. Larger cuts (25–30%+) can feel hard to sustain and may impact training.
  • How many calories should I eat to lose weight?
    First find your maintenance (TDEE), then subtract a moderate deficit. The calculator does this and returns a daily calorie target.
  • Is 1200 calories per day safe?
    For some individuals this can be too low. If your target seems unusually low, pick a smaller deficit or talk to a professional.
  • Percent vs custom kcal deficit — which is better?
    Percent scales with your TDEE across body sizes. Custom kcal is simple if you prefer a fixed reduction (e.g., −400 kcal).
  • How fast will I lose weight?
    Roughly, bigger bodies and bigger deficits lose faster. As a ballpark, a moderate deficit may yield ~0.25–1.0 kg/week, but results vary.
  • Why am I not losing weight in a deficit?
    Check consistency, logging accuracy, NEAT/activity, water retention, and weekly averages vs daily scale noise.
  • Do I need to change protein or macros?
    Higher protein can help preserve lean mass in a deficit. See Macros and Protein Intake.
  • Does intermittent fasting help?
    IF can make adherence easier for some by limiting eating windows. Energy balance (calorie deficit) remains the key driver.
  • How long to reach my goal weight?
    Enter a goal weight to see a rough time-to-goal based on your chosen deficit. Adjust if the timeline feels too slow/fast.

Disclaimer

The tools provided on this site are for educational purposes and are not a substitute for professional medical advice, diagnosis, or treatment. Consult a qualified health provider with questions about a medical condition or nutrition plan.

Equations are adult-focused estimates and may not apply to children, pregnant or breastfeeding individuals, or specific medical conditions.

References