Calorie Calculator
Mifflin-St Jeor BMR and TDEE with separate NEAT and training activity factors, gender-adjusted protein/fat targets per kg, fiber estimate, and lean-bulk safety tips. Metric or imperial.
Example use cases
Office worker, fat loss
Sedentary NEAT + 1-2×/week training → k = 1.1. TDEE ~1980 kcal, target ~1480 kcal, protein target ~95 g (70 kg male).
Female nurse, maintenance
Physical NEAT + 3-4×/week → k = 1.5. TDEE ~2100 kcal, fat target ~58 g (60 kg female). Surplus/deficit = 0.
Male athlete, lean bulk
Light NEAT + 5-6×/week → k = 1.4. TDEE ~3150 kcal, target ~3400 kcal (+250). Protein ~185 g (85 kg male).
Female beginner, lean bulk
Light NEAT + 3-4×/week → k = 1.3. Target = TDEE + 150 kcal. Safety tip highlights slower gain expectation for women.
Construction worker
Heavy NEAT + no gym → k = 1.4. TDEE ~3500 kcal for a typical male - much higher than assumed when only "no gym" is noted.
Competitive athlete
Light NEAT + elite training → k = 1.5. Protein target for a 75 kg male: ~(0.84 + 0.5) × 75 ~ 101 g; hint suggests 1.6-2.2 g/kg.
How this calculator works
Enter your stats, choose your daily activity level and structured training frequency separately, then pick a goal. The calculator outputs BMR, TDEE, target calories, estimated weekly weight change, and personalised macronutrient targets.
Two-factor activity model
k = clamp(1.0 + KNEAT + Ktrain, 1.0, 1.9)NEAT values (KNEAT): sedentary 0.0 · light 0.1 · physical 0.3 · heavy 0.4
Training values (Ktrain): none 0.0 · 1-2×/wk 0.1 · 3-4×/wk 0.2 · 5-6×/wk 0.3 · elite 0.4
Example: a desk worker who trains 3-4×/week → k = 1.0 + 0.0 + 0.2 = 1.2.
A construction worker who also trains 5-6×/week → k = 1.0 + 0.4 + 0.3 = 1.7.
Caloric target
Lose: −500 kcal (both sexes) - roughly 0.5 kg/week
Maintain: 0 kcal
Gain (men): +250 kcal - lean bulk ~0.5-1 kg/month total
Gain (women): +150 kcal - lower muscle-gain potential
Macro targets (g/day)
Fat: adjusted g/kg based on NEAT, training intensity, and goal
Carbs: remaining calories ÷ 4 kcal/g
Fiber: 0.45 × kg, clamped 20-50 g
Key terms
BMR
Basal Metabolic Rate: calories your body burns at complete rest to sustain life. Calculated here with the Mifflin-St Jeor equation.
TDEE
Total Daily Energy Expenditure: BMR multiplied by an activity factor reflecting daily movement and exercise. The baseline for setting any calorie goal.
NEAT
Non-Exercise Activity Thermogenesis: energy used through all non-workout physical activity - occupational work, walking, household tasks, fidgeting.
Protein (g/kg)
Protein is expressed per kg of body weight. Recommendations range from ~0.8 g/kg (sedentary adults) up to ~2.2 g/kg (high-volume athletes or cutting phases).
Fat (g/kg)
Dietary fat targets are set per kg of body weight based on sex, activity, and goal. Fat is essential for hormone production and fat-soluble vitamin absorption.
Fiber
Dietary fiber is estimated at 0.45 g/kg, clamped to 20-50 g/day. General guidelines recommend at least 25 g/day for adults (WHO). Supports gut health and satiety.
Frequently Asked Questions
Common questions about calorie needs, BMR, TDEE, NEAT, and macronutrient targets.
What is BMR and TDEE?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to sustain basic functions - breathing, circulation, cell repair. TDEE (Total Daily Energy Expenditure) multiplies BMR by an activity factor that accounts for daily movement and structured exercise, giving a realistic estimate of your daily calorie needs.
What is NEAT and why is it a separate factor from training?
NEAT stands for Non-Exercise Activity Thermogenesis - calories burned through everyday movement outside of intentional workouts: job type, walking, standing, fidgeting. A construction worker and a desk worker can have the same gym routine but vastly different total calorie needs. Separating NEAT from training gives a more accurate TDEE than a single activity multiplier.
Why does biological sex affect calorie and macro targets?
Sex influences the BMR intercept in the Mifflin-St Jeor formula (+5 for men, -161 for women). Beyond that, the protein and fat baselines used here differ by sex (based on WHO and Dietitians Australia guidelines), and the lean-bulk surplus is smaller for women (+150 kcal vs +250 kcal) because women have a lower muscle-building potential on average.
How are the protein and fat targets calculated?
Protein is calculated as (base g/kg + activity offset) times body weight. The base is 0.84 g/kg for men and 0.75 g/kg for women (WHO/ISSN range). Activity adds up to 0.8 g/kg for elite athletes. Fat is similarly g/kg-based, starting at 0.90 g/kg (men) or 0.95 g/kg (women), then adjusted for NEAT intensity, training volume, and goal. Carbohydrates fill the remaining calorie budget.
Can I enter pounds and inches?
Yes. Switch the toggle to Imperial. Pounds are converted to kilograms (times 0.4536) and height in inches to centimetres (times 2.54) before all calculations. The results are always shown as rounded integers.
What does the fiber estimate represent?
Fiber is estimated as 0.45 g per kg of body weight, clamped to a range of 20-50 g/day. This is a rough reference aligned with general dietary guidelines (WHO: at least 25 g/day for adults). Individual needs vary depending on food choices and health conditions.
Is this medical or dietitian advice?
No. All outputs are educational estimates only. The formulas have known error margins and do not account for medical conditions, medications, pregnancy, eating disorders, or individual metabolic variation. Anyone under 16, pregnant, or with specific health conditions should consult a qualified medical professional or registered dietitian.
About these results
This tool provides estimates for planning only. It is not a medical device, not personalised clinical nutrition, and not a substitute for professional advice. Laws, health conditions, and lab data may change what is safe for you.