Calorie Calculator — Calculate Daily Intake & TDEE Online
Calculate daily calorie needs and TDEE based on Mifflin-St Jeor equation. Supports weight loss, gain, and maintenance goals. Results in your browser.
Features
- ✓Calculate BMR (Basal Metabolic Rate) using Mifflin-St Jeor equation
- ✓Calculate TDEE (Total Daily Energy Expenditure)
- ✓Support 5 activity levels from sedentary to very active
- ✓Calculate calories for weight loss, maintenance, or gain
- ✓Based on scientifically validated formulas
- ✓Instant calculation as you type
- ✓Shows breakdown of BMR and TDEE
- ✓Adjusts calories based on your fitness goal
- ✓Works for both men and women
- ✓All calculations run locally in your browser
How to Use
- 1Enter your weight in kilograms.
- 2Enter your height in centimeters.
- 3Enter your age in years.
- 4Select your gender (male or female).
- 5Choose your activity level.
- 6Select your goal (lose weight, maintain, or gain weight).
- 7View your BMR, TDEE, and target daily calories.
- 8Adjust activity level to see how exercise affects calorie needs.
- 9Compare weight loss, maintenance, and gain targets side by side.
Frequently Asked Questions
What is BMR and TDEE?
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BMR (Basal Metabolic Rate) is the number of calories your body burns at rest to maintain basic functions like breathing and circulation. TDEE (Total Daily Energy Expenditure) is your BMR plus calories burned through activity. TDEE represents your total daily calorie needs to maintain your current weight.
What formula does this calculator use?
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The calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for modern populations. For men: BMR = 10×weight + 6.25×height - 5×age + 5. For women: BMR = 10×weight + 6.25×height - 5×age - 161.
How are weight loss/gain calories calculated?
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For weight loss: TDEE - 500 calories (creates a deficit for ~0.5 kg/week loss). For weight gain: TDEE + 500 calories (creates a surplus for ~0.5 kg/week gain). These are moderate, sustainable rates. For faster results, adjust the deficit/surplus, but consult a healthcare provider.
What activity level should I choose?
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Sedentary: Desk job, little exercise. Light: Exercise 1-3 days/week. Moderate: Exercise 3-5 days/week. Active: Exercise 6-7 days/week. Very Active: Hard exercise daily or physical job. When in doubt, choose the lower level for a conservative estimate.
Why might my actual needs differ from the calculation?
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The formula provides estimates based on averages. Individual metabolism varies due to genetics, muscle mass, health conditions, and other factors. Use this as a starting point and adjust based on your results over 2-3 weeks. Track your weight and adjust calories as needed.
Is my health data sent to a server?
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No. All calculations happen entirely in your browser using JavaScript. Your weight, height, age, and calorie results are never transmitted over the network. The tool works offline after the page loads.
How many calories should I eat to lose 1 kg per week?
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To lose approximately 1 kg per week, you need a daily deficit of about 1,100 calories (since 1 kg of fat ≈ 7,700 calories). This is aggressive and may not be safe for everyone. Most health organizations recommend 0.5-1 kg per week maximum. Start with a 500-calorie deficit for sustainable weight loss.
Does muscle mass affect BMR?
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Yes significantly. Muscle tissue burns more calories at rest than fat tissue (roughly 3x more). This is why the Mifflin-St Jeor formula includes weight but doesn't directly account for body composition. Strength training to build muscle will naturally increase your BMR over time.
Is the Mifflin-St Jeor formula better than Harris-Benedict?
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Yes. The Mifflin-St Jeor equation, developed in 1990, is considered more accurate for modern populations than the older Harris-Benedict formula (1919). Studies show Mifflin-St Jeor estimates BMR within 10% of measured value for most people, making it the recommended formula by the Academy of Nutrition and Dietetics.
What is a calorie deficit and how much should I aim for?
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A calorie deficit means consuming fewer calories than your TDEE. A deficit of 300-500 calories per day leads to safe weight loss of about 0.25-0.5 kg per week. A deficit of 500-1,000 calories can lead to 0.5-1 kg per week but should be monitored. Deficits over 1,000 calories daily are generally not recommended without medical supervision as they can lead to muscle loss and nutritional deficiencies.
How does age affect my calorie needs?
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BMR naturally decreases with age — about 1-2% per decade after age 20 due to muscle mass loss and hormonal changes. This is why middle-aged adults often need fewer calories than younger adults of the same weight and height. Strength training can partially offset this decline by maintaining or building muscle mass.
What's the difference between calories and kilocalories?
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In nutrition, 'calories' actually refer to kilocalories (kcal). One food Calorie (capital C) equals 1,000 small calories (cal), which is the same as 1 kilocalorie. So when the calculator shows 2,000 kcal, that's the same as 2,000 food Calories. The terms are used interchangeably in dietary contexts.
How does intermittent fasting affect TDEE calculations?
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Intermittent fasting doesn't change the basic TDEE calculation — your body still burns the same number of calories regardless of when you eat. However, fasting can affect hunger hormones and may help people naturally eat less. The TDEE-based calorie targets remain valid regardless of your eating schedule. Focus on total daily intake rather than meal timing.
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