Calorie Calculator
Calculate BMR and TDEE for weight management. Supports Mifflin-St Jeor and Harris-Benedict formulas.
Calorie Calculator
What is a Calorie Calculator?
A calorie calculator is a health management tool that computes your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) based on your personal body measurements and activity level, providing the exact calorie intake needed for effective weight management. It delivers the most fundamental information for anyone starting a diet or looking to build muscle.
Using scientifically validated Mifflin-St Jeor and Harris-Benedict formulas, this calculator considers your gender, age, height, weight, and activity level to provide personalized calorie recommendations. Results are displayed in real-time as you type, allowing you to quickly compare different scenarios.
When to Use This Calculator
- Starting a Diet – When you need to determine the right daily calorie intake for weight loss
- Bulking/Muscle Gain – When calculating the calorie surplus needed to build muscle mass
- Meal Planning – Before consulting a nutritionist, understand your baseline metabolic rate and recommended calories
- Workout Planning – Predict how changes in exercise intensity or frequency will affect your calorie burn
- Weight Maintenance – After reaching your goal weight, confirm the calories needed to maintain it
- General Health – Understand your body’s energy metabolism and plan healthy lifestyle habits
Key Features
- Two Validated Formulas – Choose between the Mifflin-St Jeor formula (considered more accurate in modern research) and the traditional Harris-Benedict formula. Compare results from both to find what works best for you.
- 5-Level Activity Selection – Select from sedentary to very active with detailed activity levels that accurately reflect your daily movement. Each level applies specific activity multipliers for realistic TDEE calculations.
- Automatic Goal-Based Calories – Instantly see calories for weight loss (-500kcal), maintenance, and weight gain (+500kcal) side by side for easy comparison.
- Visual Chart Comparison – BMR, TDEE, and loss/gain calories are visualized in bar charts for intuitive understanding.
- Projected Weight Change – Automatically calculates and displays expected weekly and monthly weight changes with a 500kcal deficit/surplus.
- Copy Results – Copy all calculated results to clipboard for sharing with meal trackers, trainers, or saving to notes.
How to Use
- Select Formula – Choose Mifflin-St Jeor (recommended) or Harris-Benedict from the tabs at the top. Switch between formulas to compare results.
- Enter Body Information – Input your gender, age, height (cm), and weight (kg) in order. Use recently measured values for accurate results.
- Choose Activity Level – Select the level from the dropdown that best matches your typical daily activity. When unsure, selecting one level lower is recommended.
- Review Results – BMR, TDEE, and goal-specific calories are automatically calculated as you input. Check the charts and projected weight changes as well.
- Use Results – Click “Copy Results” to save or share your calculations. Paste into meal tracking apps or notes for ongoing management.
Understanding Basal Metabolic Rate (BMR)
Basal Metabolic Rate (BMR) is the minimum amount of energy your body needs to sustain life. Even in complete rest—lying down doing nothing—your body consumes energy for breathing, blood circulation, cell regeneration, temperature regulation, and brain activity. BMR typically accounts for 60-75% of your total daily energy expenditure.
BMR tends to decrease with age, largely due to muscle mass loss. Since muscle is more metabolically active than fat and burns more energy, having more muscle mass results in a higher BMR. Regular strength training can help maintain or increase your BMR.
TDEE and Energy Balance
Total Daily Energy Expenditure (TDEE) is your BMR plus the energy burned through daily activities and exercise. TDEE consists of three main components:
- BMR (60-75%) – Basal metabolic rate, the minimum energy for life support
- TEF (10%) – Thermic Effect of Food, energy required to digest and absorb food
- Activity Energy (15-30%) – Energy used for daily activities and exercise
The key to weight management is energy balance. Consuming fewer calories than your TDEE leads to weight loss; consuming more leads to weight gain. For safe and sustainable weight change, maintaining a daily deficit or surplus of 300-500kcal is recommended.
Formula Comparison
Mifflin-St Jeor Formula (1990, Recommended)
- Male: BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age + 5
- Female: BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age – 161
Developed in 1990 by Mark Mifflin and Sachiko St Jeor, this formula better reflects modern body compositions and lifestyles. Multiple studies have evaluated it as the most accurate BMR estimation formula, and it’s recommended by the Academy of Nutrition and Dietetics.
Harris-Benedict Formula (1919)
- Male: BMR = 88.362 + 13.397 × weight(kg) + 4.799 × height(cm) – 5.677 × age
- Female: BMR = 447.593 + 9.247 × weight(kg) + 3.098 × height(cm) – 4.330 × age
Developed in 1919 by James Harris and Francis Benedict, this is the oldest BMR estimation formula. With over 100 years of history, it’s still used in many publications and tools, but tends to overestimate by 5-15% for modern populations due to changes in average body composition and lifestyle.
Activity Level Details
- Sedentary (×1.2) – Desk job, remote work, rarely exercises. Mostly sitting aside from commuting.
- Light Activity (×1.375) – Light exercise 1-3 times per week (brisk walking, light jogging, yoga) or standing occupation.
- Moderate Activity (×1.55) – Moderate exercise 3-5 times per week (running, swimming, weight training). This is where most people fall.
- Active (×1.725) – Exercise 6-7 times per week or physically demanding occupation (construction workers, farmers, etc.).
- Very Active (×1.9) – Professional athletes, daily high-intensity training, multiple workouts per day, or very demanding physical labor.
Tips for Healthy Weight Management
- Avoid Extreme Calorie Restriction – Eating below your BMR can cause muscle loss, metabolic slowdown, and nutritional deficiencies. Reduce by a maximum of 500-750kcal from TDEE.
- Maintain Protein Intake – Even while losing weight, consuming 1.6-2.2g of protein per kg of body weight helps minimize muscle loss.
- Take a Gradual Approach – Rapid weight changes exceeding 0.5-1kg per week can be harmful to health. Progress slowly and steadily toward your goals.
- Recalculate Regularly – Recalculate your TDEE when your weight changes by 5kg or more. Your calorie needs change as your weight changes.
- Consult Professionals – If you have underlying health conditions or are in special situations (pregnancy, breastfeeding, etc.), always consult healthcare professionals before planning your diet.
Frequently Asked Questions
Which is more accurate: Mifflin-St Jeor or Harris-Benedict formula?
Modern research indicates that the Mifflin-St Jeor formula is more accurate. Developed in 1990, it better reflects the body composition and lifestyle of modern individuals. The Harris-Benedict formula, created in 1919, has a long history but tends to overestimate calorie needs by 5-15% for today’s population, which is why the Academy of Nutrition and Dietetics recommends Mifflin-St Jeor.
What’s the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the minimum calories your body needs at complete rest for life-sustaining functions like breathing, heartbeat, and temperature regulation. TDEE adds daily activities (walking, exercising, working) to BMR, representing your actual daily calorie expenditure. Weight management plans should be based on TDEE, not BMR, and eating below your BMR can be harmful to your health.
Will a 500 kcal deficit really result in 0.5kg weight loss per week?
One kilogram of body fat stores approximately 7,700 kcal of energy. A daily deficit of 500 kcal × 7 days = 3,500 kcal, theoretically allowing for about 0.45kg of fat loss. However, actual results vary due to water fluctuations, muscle mass changes, metabolic adaptation, and hormonal changes. The first 1-2 weeks often show greater loss due to water reduction, followed by more stable rates.
How should I choose my activity level?
The most common mistake is overestimating your activity level. If you have an office job, even going to the gym 3 times a week means “Moderate Activity” is appropriate. “Active” or “Very Active” applies to athletes, delivery drivers, construction workers—people who move their bodies all day. When unsure, select one level lower and observe your weight changes over 2-4 weeks, then adjust accordingly.
I’m eating according to my calculated calories but not losing weight. Why?
There could be several reasons. First, you might be underestimating your calorie intake. Drinks, sauces, and snacks can add significant untracked calories—try using a food scale and calorie tracking app for accurate logging. Second, you may have overestimated your activity level; try recalculating with one level lower. Third, if you’ve been dieting for a while, metabolic adaptation may have lowered your TDEE. If you’ve plateaued for more than 2 weeks, recalculate or consult a professional.
Is my entered information saved or sent anywhere?
No, all calculations are processed by JavaScript within your browser. Your body information (age, height, weight, etc.) is not sent to any server and is not stored externally. For convenience, data may be temporarily saved in your browser’s local storage, but this remains only on your device and can be deleted at any time.