Calorie Calculator — TDEE & BMR Maintenance Tracker

What is TDEE and BMR?

When planning a diet for weight loss or muscle gain, understanding your energy requirements is the foundational first step. Two critical metrics govern this:

Basal Metabolic Rate (BMR): The number of calories your body requires to perform basic life-sustaining functions (breathing, circulation, cell production) if you were to rest in bed all day.
Total Daily Energy Expenditure (TDEE): Your BMR multiplied by your daily physical activity. This represents the total number of calories you burn in a 24-hour period.

The Mifflin-St Jeor Equation

There are several formulas to calculate BMR, but the Mifflin-St Jeor Equation is widely considered by the medical community and dietitians to be the most accurate for the modern population. Our calculator uses this exact formula:

Men: (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
Women: (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161

How to Use Maintenance Calories

Your TDEE is often referred to as your "Maintenance Calories". If you consume exactly this amount of calories every day, your body weight will remain identical.

To Lose Fat (Cutting): You must eat in a "caloric deficit". A standard, sustainable deficit is 500 calories below your TDEE, which results in approximately 0.5kg (1 lb) of fat loss per week.
To Gain Muscle (Bulking): You must eat in a "caloric surplus". A standard lean bulk requires consuming 300 to 500 calories above your TDEE combined with progressive resistance training.

Calorie Calculator: Master Your Energy Balance

At its core, weight management is a matter of Energy Balance: calories in versus calories out. Whether you want to lose fat, build muscle, or maintain your current physique, you must first know your "Maintenance Calories." Our Calorie Calculator uses the Mifflin-St Jeor equation to estimate your BMR and TDEE, giving you a precise starting point for your nutrition journey.

Formula

TDEE = BMR × Activity Factor

BMR = 10*weight(kg) + 6.25*height(cm) - 5*age(y) + s (s is +5 for men, -161 for women)

BMR vs. TDEE: Understanding the Difference

BMR (Basal Metabolic Rate) is the energy your body needs for basic functions like breathing and heart rate—imagine lying in bed all day. TDEE (Total Daily Energy Expenditure) includes your BMR plus the calories burned through walking, working, and exercise. Your TDEE is your true 'Maintenance' number. If you eat exactly your TDEE, your weight will stay the same.

Setting Your Weight Loss Deficit

To lose weight safely, you should aim for a daily deficit of 300 to 500 calories below your TDEE. This typically leads to a steady weight loss of 0.25kg to 0.5kg per week. Aggressive deficits (over 1000 calories) are often unsustainable and lead to significant muscle loss and 'crashes' in energy and mood.

Building Muscle: The Caloric Surplus

Muscle growth (Hypertrophy) requires a Caloric Surplus—eating more than you burn. However, eating too much leads to excessive fat gain. A 'Lean Bulk' usually involves eating 200-300 calories above maintenance combined with intense resistance training. This provides the body with the extra energy required to synthesize new muscle tissue without adding significant body fat.

The Role of Activity Levels

Activity levels are often the most misunderstood part of calorie calculation. 1) Sedentary: Desk job, little to no exercise. 2) Moderate: 3-5 days of exercise. 3) Active: Daily exercise or a physically demanding job. Be honest with your selection; overestimating activity is the #1 reason people fail to see results from online calculators.

Practical Examples

Weight Loss Goal

A 30-year old male (80kg) wanting to lose 2kg/month.

1.Maintenance (TDEE): 2,400 kcal
2.Daily Deficit: -500 kcal
3.Target Intake: 1,900 kcal
4.Result: Steady fat loss while maintaining energy.

Lean Bulk Goal

A 25-year old female (55kg) wanting to build muscle.

1.Maintenance (TDEE): 1,800 kcal
2.Daily Surplus: +200 kcal
3.Target Intake: 2,000 kcal
4.Result: Gradual muscle gain with minimal fat.

Factors That Influence Your Metabolism

Muscle Mass: More muscle means a higher BMR (muscle burns more than fat).

Age: BMR naturally declines as we get older.

Hormones: Thyroid issues or PCOS can significantly alter calorie needs.

Genetics: Some people naturally have a higher NEAT (fidgeting, movement).

Body Size: Larger bodies require more energy to move and maintain.

Frequently Asked Questions

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body burns just to stay alive at rest (breathing, pumping blood, etc.).

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total calories you burn in a day, including exercise and daily movement. This is your 'Maintenance' number.

How many calories to lose 1kg of fat?

Roughly 7,700 calories. To lose 0.5kg a week, you need a daily deficit of about 500 calories.

Why is weight loss slow despite a deficit?

Metabolic adaptation, water retention, or inaccurate tracking (underestimating portions) are common reasons. Consistency over weeks is key.

Should I eat my exercise calories back?

Generally, no. Most fitness trackers overestimate calories burned. Our calculator already includes your activity level in the TDEE estimate.

What is the Mifflin-St Jeor equation?

It is currently the most accurate formula for estimating BMR for the average person, used by our calculator.

Does age affect calorie needs?

Yes, metabolism typically slows down by about 1-2% per decade after the age of 30, mainly due to muscle loss.

How much protein should I eat in a deficit?

High protein (1.6g to 2.2g per kg of body weight) is crucial during weight loss to prevent muscle breakdown.

What is 'Starvation Mode'?

It's a myth that your body stops losing weight if you eat too little. However, extreme deficits can cause severe lethargy and hormonal issues.

How accurate are calorie calculators?

They provide a very good starting estimate (usually within 10%). You should adjust your intake based on how your weight changes over 2-3 weeks.

Calorie Calculator (TDEE)

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