☾ Calorie & TDEE Calculator
Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure using the Mifflin-St Jeor formula.
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Start Free AI Coaching ✦🧬 Understanding TDEE & Your Cycle
TDEE (Total Daily Energy Expenditure) represents how many calories your body burns in a full day, including exercise. It's calculated from your BMR (calories burned at rest) multiplied by an activity factor.
✦ What's the difference between BMR and TDEE? ↓
BMR (Basal Metabolic Rate) is the energy your body needs just to keep you alive at complete rest — breathing, circulation, cell repair. TDEE adds in physical activity, digestion, and daily movement. You should never eat below your BMR.
✦ How does my menstrual cycle affect calorie needs? ↓
During the luteal phase, your basal body temperature rises and your metabolism speeds up by 5–10%. This means you naturally burn more calories and may feel hungrier. In the follicular phase, your body is more insulin-sensitive, making it a good time for moderate calorie management.
✦ Is a 500-calorie deficit safe? ↓
A 500 kcal/day deficit typically leads to ~0.5 kg (1 lb) of fat loss per week, which is generally safe. However, aggressive deficits can disrupt your menstrual cycle (hypothalamic amenorrhea). If your period becomes irregular, increase your intake.
✦ What is metabolic adaptation and how do I avoid it? ↓
Metabolic adaptation is your body's defense mechanism against starvation — it reduces BMR by 10–15% during prolonged calorie restriction. To minimize it: take diet breaks (eat at maintenance for 1–2 weeks every 8–12 weeks of deficit), maintain strength training to preserve muscle mass, and avoid deficits larger than 25% of TDEE.
✦ Should I eat back my exercise calories? ↓
TDEE already includes your exercise factor, so if you calculated your target using the correct activity level, your exercise calories are already accounted for. If you track additional workouts beyond your stated level, eating back 50% of those extra calories is a reasonable approach — fitness trackers tend to overestimate calorie burn by 20–40%.
✦ Why does my TDEE calculator result differ from my fitness watch? ↓
Fitness watches use heart rate and motion sensors to estimate calorie burn, while TDEE calculators use population-level equations. Both have margins of error (±10–15%). For the most accurate picture, use your TDEE calculator result as a starting point, track your weight for 2–3 weeks, and adjust by ±100–200 kcal based on actual weight trends.
📖 Step-by-Step Calorie Calculation
Enter your weight, height, age, gender, and activity level. The calculator uses the Mifflin-St Jeor equation — the most accurate resting metabolic rate formula validated across clinical studies — to compute your BMR, then multiplies it by your activity factor to produce TDEE.
Be honest about your activity level. Most people overestimate their activity multiplier. If you exercise 3 times per week but have a desk job, 'Lightly Active' is usually more accurate than 'Moderately Active.' The difference can be 200–400 calories per day.
📊 What Your TDEE Numbers Mean
BMR is the number of calories your body needs just to maintain basic life functions at complete rest. TDEE is your true daily burn including all physical activity and digestion. The weight loss target applies a 20% deficit, and the lean gain target adds a 10% surplus.
Never eat below your BMR — doing so for extended periods triggers metabolic adaptation (your body slows its metabolism to conserve energy) and can cause menstrual disruption. A sustainable deficit sits between BMR and TDEE, typically 300–500 kcal below TDEE.
⚕️ When Calorie Restriction Requires Medical Oversight
Seek guidance from a registered dietitian or physician if you plan to eat below 1,200 kcal/day, if you've experienced hair loss, chronic fatigue, or missed periods during a calorie deficit, or if you have a history of eating disorders. Very low calorie diets (VLCDs) below 800 kcal/day should only be followed under clinical supervision due to risks of gallstones, muscle wasting, and cardiac complications.