Calorie Calculator
Find out exactly how many calories you need each day to maintain, lose, or gain weight.
📖 What is a Calorie Calculator?
A calorie calculator estimates your Total Daily Energy Expenditure (TDEE) - the total number of calories your body burns each day. Knowing your TDEE is the starting point for any nutrition goal: weight loss, maintenance, or muscle gain. Without understanding your calorie needs, adjusting your diet becomes guesswork.
This calculator uses the Mifflin-St Jeor equation, the gold standard for estimating Basal Metabolic Rate (BMR) - the calories your body burns at complete rest just to keep organs functioning. BMR is then multiplied by an activity factor to account for exercise and daily movement.
The result is your maintenance calorie intake. Eat below this to lose weight; eat above it to gain. The calculator also shows calorie targets for common goals: a 500 kcal/day deficit (approx 0.5 kg/week loss), a milder 250 kcal/day deficit, and a 300 kcal/day surplus for lean muscle gain.
Understanding calorie balance is foundational to nutrition science. While calorie counting isn't the only approach to healthy eating, it remains the most evidence-backed method for achieving specific weight goals. Combined with attention to protein, micronutrients, and food quality, calorie awareness is a powerful tool.
📐 Formula
BMR (Mifflin-St Jeor):
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
TDEE = BMR × Activity Factor
Activity factors:
Sedentary: 1.2
Lightly active: 1.375
Moderately active: 1.55
Very active: 1.725
Extra active: 1.9
Weight loss: TDEE − 500 kcal/day ≈ −0.5 kg/week
Weight gain: TDEE + 300 kcal/day
📖 How to Use This Calculator
1
Select Metric or Imperial units.
2
Enter your age, sex, weight, and height.
3
Select your activity level - be honest; most people overestimate.
4
Click Calculate - your TDEE and goal-based calorie targets appear.
💡 Example Calculations
Example 1 - 30-year-old man, 80 kg, 178 cm, moderately active
1
BMR = 10×80 + 6.25×178 − 5×30 + 5 = 800 + 1112.5 − 150 + 5 = 1,767.5 kcal
2
TDEE = 1,767.5 × 1.55 = 2,740 kcal/day
3
To lose 0.5 kg/week: 2,240 kcal/day
Example 2 - 25-year-old woman, 60 kg, 163 cm, lightly active
1
BMR = 10×60 + 6.25×163 − 5×25 − 161 = 600 + 1018.75 − 125 − 161 = 1,332.75 kcal
2
TDEE = 1,332.75 × 1.375 = 1,832 kcal/day
3
Maintenance: 1,832 kcal/day | Weight loss: 1,332 kcal/day
Frequently Asked Questions
What is TDEE?
TDEE stands for Total Daily Energy Expenditure - the total number of calories your body burns in a day, including your basal metabolic rate (BMR) plus calories burned through activity and digestion. To maintain your weight, you need to eat calories equal to your TDEE. To lose weight, eat below TDEE; to gain, eat above it.
What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation (1990) is considered the most accurate BMR formula for most people. It is: For men: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5. For women: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161. The BMR is then multiplied by an activity factor to get TDEE.
Which activity level multiplier should I use for my TDEE?
Most people overestimate their activity level. Use sedentary (×1.2) if you have a desk job and do little exercise. Lightly active (×1.375) means 1–3 days of exercise per week. Moderately active (×1.55) means 3–5 days. Very active (×1.725) means 6–7 hard workouts per week. Extra active (×1.9) applies to athletes training twice daily or those with physically demanding jobs. When in doubt, choose one level lower than you think - it is easier to eat more than to explain stalled weight loss from an overestimated TDEE.
Does muscle affect calorie needs?
Yes, significantly. Muscle is metabolically active - it burns more calories at rest than fat. Two people with the same weight can have very different calorie needs if their body composition differs. This is why resistance training during weight loss helps preserve metabolism.
Why does my calorie need change as I lose weight?
As you lose weight, your BMR decreases because there is less body mass to maintain. This is called metabolic adaptation. You should recalculate your TDEE every 4–6 weeks or every 5 kg of weight change to keep your calorie target accurate.
How do I adjust my calorie target as I lose weight?
As you lose weight your BMR decreases because there is less body mass to maintain. This is called metabolic adaptation. Recalculate your TDEE every 4–6 weeks or after every 5 kg of weight change by entering your new weight into the calculator. Without adjustment, your original deficit gradually shrinks and weight loss slows. Most people need to reduce intake by 50–100 kcal per recalculation to maintain the same rate of fat loss.
Does calorie counting work for weight loss?
Yes. Calorie balance is the primary driver of weight change. Consistent calorie tracking leads to greater weight loss than intuitive eating in most controlled studies. However, calorie counts on labels can be off by 10-20%, and digestion efficiency varies between people. The most effective approach combines calorie awareness with sustainable food habits that prioritise protein and fibre to naturally control hunger.
How accurate are online TDEE calculators?
Online TDEE calculators are estimates based on population averages and have a typical accuracy range of plus or minus 10-15%. Individual metabolic rates vary due to genetics, hormonal factors, gut microbiome, and body composition. The best approach is to use the calculated TDEE as a starting point, track your weight for 2-3 weeks while eating at that calorie level, then adjust up or down by 100-200 kcal based on actual results. Real-world data from your own body is more accurate than any formula.
How many calories should I eat to lose 0.5 kg per week?
0.5 kg of body fat is approximately 3,500 kcal. To lose 0.5 kg/week, create a daily calorie deficit of 500 kcal. Calculate your TDEE using this calculator, then subtract 500. For most adults, this means eating 1,400-1,900 kcal/day. Avoid deficits exceeding 1,000 kcal/day - this risks muscle loss and metabolic adaptation.
How accurate are online calorie calculators?
Calorie calculators estimate TDEE within 10-20% for most people. Individual variation in metabolism, body composition, gut microbiome, and non-exercise activity thermogenesis (NEAT) creates significant spread. Use the calculator result as a starting point, track your weight for 2-3 weeks, and adjust calories by 100-200 kcal if weight is not trending as expected. Real-world feedback beats any formula.