Calorie Calculator
Calculate your daily calorie needs using the Mifflin-St Jeor formula. Get BMR, TDEE, calorie target by goal, BMI, and suggested macros instantly.
Calorie Calculator is a free online tool that estimates your daily calorie needs based on your body measurements, activity level, and weight goal. It uses the Mifflin-St Jeor equation — the most validated BMR formula in clinical nutrition research — to calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
How It Works
The calculator follows three steps:
- BMR (Basal Metabolic Rate) — The number of calories your body needs to maintain basic functions (breathing, circulation, cell repair) while completely at rest.
- TDEE (Total Daily Energy Expenditure) — BMR multiplied by an activity factor to estimate how many calories you actually burn each day.
- Calorie Target — TDEE adjusted up or down based on your goal (lose weight, maintain, or gain weight).
The Mifflin-St Jeor Formula
| Sex | Formula |
|---|---|
| Male | BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 |
| Female | BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161 |
TDEE is then calculated as:
| Activity Level | Multiplier |
|---|---|
| Sedentary (little/no exercise) | BMR × 1.2 |
| Lightly active (1–3 days/week) | BMR × 1.375 |
| Moderately active (3–5 days/week) | BMR × 1.55 |
| Very active (6–7 days/week) | BMR × 1.725 |
| Extra active (physical job) | BMR × 1.9 |
Weight Goals and Calorie Adjustments
A deficit or surplus of approximately 7,700 kcal corresponds to roughly 1 kg of body weight change. The goals use:
| Goal | Daily Adjustment |
|---|---|
| Lose ~0.5 kg/week | −500 kcal/day |
| Lose ~0.25 kg/week | −250 kcal/day |
| Maintain weight | ±0 kcal/day |
| Gain ~0.25 kg/week | +250 kcal/day |
| Gain ~0.5 kg/week | +500 kcal/day |
Suggested Macronutrients
Based on your calorie target, the tool suggests a balanced macro split (30% protein / 40% carbs / 30% fat), which is a commonly recommended starting point. Each gram of protein and carbohydrate provides 4 kcal; each gram of fat provides 9 kcal.
How to Use
- Select your unit system (Metric: kg/cm or Imperial: lb/ft/in).
- Choose your biological sex, enter your age, height, and weight.
- Select your activity level — be honest for the most accurate result.
- Choose your goal. Results update instantly.
- Review your BMR, TDEE, daily calorie target, BMI, and suggested macros.
FAQ
What is BMR?
Basal Metabolic Rate is the number of calories your body burns at complete rest — just to keep you alive. It accounts for roughly 60–75% of total daily calorie expenditure for most sedentary people.
What is TDEE?
Total Daily Energy Expenditure is the total number of calories you burn in a day, including physical activity. Eating at your TDEE means your weight stays stable over time.
How accurate is this calculator?
The Mifflin-St Jeor formula is the most accurate general-population BMR formula available for non-clinical use, with a margin of error of roughly ±10%. Individual factors such as muscle mass, hormones, medications, and metabolic conditions can cause variation. Use this as a starting estimate and adjust based on real-world results over 2–4 weeks.
What is BMI and should I rely on it?
BMI (Body Mass Index) is a simple ratio of weight to height squared. It is a rough screening tool, not a precise health measure. It does not account for muscle mass, bone density, or body fat distribution. Athletes often have a high BMI without excess fat.
Can I lose weight faster than 0.5 kg per week?
Rapid weight loss beyond this rate increases the risk of muscle loss, nutritional deficiencies, and metabolic adaptation. Most health organisations recommend a maximum deficit of 500–1000 kcal/day for safe fat loss.
Should I eat below my BMR?
Eating significantly below your BMR for extended periods is not recommended without medical supervision. It can cause muscle loss, fatigue, hormonal disruption, and nutrient deficiencies.