Calorie & TDEE Calculator
Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor formula.
Knowing roughly how many calories your body burns in a day is the foundation of almost any nutrition goal, whether you want to lose fat, gain muscle, or simply maintain your weight without guesswork. This calculator estimates your Total Daily Energy Expenditure (TDEE) using the well-regarded Mifflin-St Jeor equation and an activity multiplier, giving you a realistic daily calorie target rather than a one-size-fits-all number.
Your TDEE is the number of calories that keeps your weight stable. Eat consistently below it and you lose weight; eat above it and you gain. By grounding your plan in your own age, sex, height, weight, and activity level, the tool replaces vague advice like "eat less" with a concrete starting figure you can adjust. It is the difference between dieting blindly and dieting with a budget.
Plug in some numbers —
we'll crunch.
How to use
- 1Select your biological sex (affects the BMR formula).
- 2Enter your age, weight in kilograms, and height in centimetres.
- 3Choose your activity level — be honest, most people are sedentary or lightly active.
- 4See your BMR (calories at rest) and TDEE (total daily needs).
- 5Use the weight loss/gain targets as calorie goals.
How it works
The calculation has two stages. First it finds your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest just to stay alive — using the Mifflin-St Jeor formula, which is regarded as the most accurate of the common equations. For men: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5; for women the final constant is −161 instead of +5.
Second, it multiplies your BMR by an activity factor to estimate your TDEE — the total you actually burn including movement and exercise. The standard multipliers run from about 1.2 for sedentary (desk job, little exercise) up to roughly 1.9 for very heavy training or physical labor. To change your weight, you create a calorie surplus or deficit relative to that TDEE; a deficit of about 500 calories a day corresponds to roughly half a kilogram (one pound) of fat loss per week.
Worked examples
Maintenance for an active woman
A 30-year-old woman, 165 cm, 65 kg, who exercises moderately 3–5 days a week.
- BMR = 10×65 + 6.25×165 − 5×30 − 161 = 650 + 1,031 − 150 − 161 = 1,370.
- Apply the 'moderate' multiplier ≈ 1.55: 1,370 × 1.55 ≈ 2,124.
Her TDEE is roughly 2,100 calories a day to maintain weight. To lose about half a kilo a week, she would aim for around 1,600 calories.
Building a weight-loss target
A man with a calculated TDEE of 2,600 calories wants steady fat loss.
- Choose a moderate daily deficit of 500 calories.
- Target intake = 2,600 − 500 = 2,100 calories.
Eating about 2,100 calories a day projects to roughly 0.5 kg of fat loss per week. Larger deficits speed results but are harder to sustain and risk muscle loss.
Tips & common mistakes
Be honest about your activity level — this is where most estimates go wrong. People routinely overestimate how active they are, picking 'very active' for what is really a desk job with a few gym sessions. When in doubt, choose the lower multiplier and adjust based on real-world results over two to three weeks.
Treat the number as a starting estimate, not gospel. These equations are population averages; your true expenditure can vary by a few hundred calories due to genetics, muscle mass, and non-exercise movement. The smart approach is to eat at the calculated target for a couple of weeks, track your weight trend, and nudge the number up or down based on what actually happens on the scale.
Avoid extreme deficits. Cutting far below your BMR may produce fast initial loss but tends to cost muscle, slow your metabolism, and backfire through bingeing. A moderate 300–500 calorie deficit, paired with adequate protein and resistance training, preserves muscle and is far more sustainable. This tool provides general estimates for education only and is not medical or dietary advice — consult a doctor or registered dietitian before making significant changes, especially if you have a health condition.
Frequently asked questions
⚠ For informational purposes only. Individual calorie needs vary. Consult a registered dietitian for personalized nutrition advice.
Last reviewed: June 2026
About this calculator
Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor formula.