About the Calorie Calculator

What it does

Estimates daily energy needs. Computes Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). Suggests calories for maintain, lose, or gain.

Core ideas

• BMR: Energy your body needs at rest.
• TDEE: BMR × activity factor. Your daily burn.
• Calorie deficit: Eat below TDEE to lose fat.
• Calorie surplus: Eat above TDEE to gain weight.

Formulas

BMR (Mifflin–St Jeor):
  Men:    BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + 5
  Women:  BMR = 10·weight(kg) + 6.25·height(cm) − 5·age − 161

TDEE = BMR × ActivityFactor

Common activity factors:
  Sedentary 1.2      Light 1.375
  Moderate  1.55     Very  1.725
  Extra     1.9

Targets:
  Maintain = TDEE
  Lose     = TDEE − deficit%
  Gain     = TDEE + surplus%
      

Fields in this calculator

• Age: Years. Used in BMR.
• Sex: Male or female. Selects BMR equation constant.
• Height: In centimeters (or feet/inches if supported). Used in BMR.
• Weight: In kilograms (or pounds if supported). Used in BMR.
• Activity Level: Sedentary to Extra active. Multiplies BMR to get TDEE.
• Goal: Maintain, lose, or gain.
• Rate (optional): % deficit or surplus. Typical fat loss 10–20% deficit. Typical gain 5–15% surplus.
• Protein target (optional): g/kg body weight (e.g., 1.6–2.2 g/kg) to preserve or build muscle.
• Carbs/Fats split (optional): Percent of remaining calories after protein.
• Units: Metric or imperial. Internally converted to kg and cm.

Macronutrient breakdown (if enabled)

Protein kcal = protein_g × 4
Fat kcal     = fat_g × 9
Carb kcal    = carb_g × 4
protein_g = protein_per_kg × weight_kg
fat_kcal = target_kcal × fat_percent
carb_kcal = target_kcal − protein_kcal − fat_kcal
carb_g = carb_kcal / 4
      

Interpreting results

• BMR: Resting need. Do not eat below this for long without medical oversight.
• TDEE: Maintenance estimate. Daily calories to keep weight stable.
• Target calories: What to eat for your goal.
• Macros: Daily grams of protein, carbs, and fat if selected.

Advantages

• Fast estimate from basic inputs.
• Actionable daily calorie target and macro plan.

Limitations

• Equations are population averages. Individual metabolism varies.
• Activity factor is a rough category, not a measured value.
• Fluid shifts and glycogen can mask short-term fat change.

How to use it well

• Pick the most honest activity level. When unsure, choose lower.
• Track body weight and waist weekly. Adjust calories by ±5–10% based on 2–4 weeks of trend.
• Prioritize protein, whole foods, sleep, and resistance training.
• Avoid extreme deficits for long periods.

Educational estimate. Not medical advice. Consult a clinician if you have health conditions, are pregnant, or are under 18.