BMR & Calorie Calculator (TDEE)

What it measures

This calculator estimates your Basal Metabolic Rate (BMR) — the number of kilocalories your body needs at complete rest to maintain basic functions such as breathing, circulation, and cell repair — and your Total Daily Energy Expenditure (TDEE), which adjusts BMR for your typical activity level. TDEE represents the calories you need each day to maintain your current weight.

How it works

You enter your biological sex, age, height, and weight. The calculator applies the Mifflin-St Jeor equation (1990) — currently the formula most recommended by dietetic associations for healthy adults — to produce your BMR. Your BMR is then multiplied by a standard activity factor (the Harris-Benedict activity scale) to give your TDEE. The whole calculation takes under two minutes.

Tips for an accurate result

• 1Track weight trends, not daily fluctuations — Body weight can vary by 1–2 kg day to day due to fluid, food, and hormones. Look at a weekly average over several weeks to judge whether your intake is at, above, or below maintenance.
• 2Gradual change is more sustainable — A deficit of 250–500 kcal/day is generally recommended for slow, steady weight loss (approximately 0.25–0.5 kg per week). Very large deficits risk muscle loss, nutrient shortfalls, and rebound.
• 3Protein intake matters — Whether losing or gaining weight, adequate protein (around 1.2–2.0 g per kg of body weight per day, per current sports-nutrition guidelines) helps preserve lean mass.
• 4Revisit the calculation if your circumstances change — A change in activity level, significant weight loss or gain, or a new health condition can all shift your energy needs. Recalculate every few months or after major changes.
• 5Consult a professional for medical weight management — If you have a health condition, are on medication, or have a history of disordered eating, work with a registered dietitian or GP rather than relying on a calculator alone.