Calorie Calculator
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Calorie basics
What Is a Calorie?
A calorie is a unit of energy. In nutrition, calories show how much energy you get from the food and drinks you consume.
Personal inputs
Why Your Calorie Target Changes
Your daily calorie requirement is not a static medical number. It changes with physical, lifestyle, and environmental factors.
- Age
- Daily calorie needs usually change with age because body size, muscle mass, hormones, and activity patterns change over time.
- Weight and height
- Larger bodies usually require more baseline energy to support basic body functions and daily movement.
- Activity level
- Walking, exercise, job demands, and non-exercise movement can move your daily target far above BMR.
- Lifestyle and health factors
- Hormones, medications, sleep quality, stress levels, muscle mass ratio, body fat percentage, and medical conditions can affect real calorie needs.
Getting started
How to Use This Calorie Calculator
Use the result as a starting point, then adjust after tracking your real progress for a few weeks.
- 1
Enter your age
Use your current age in years.
- 2
Select your sex
The BMR equations use different constants for male and female inputs.
- 3
Enter your height and weight
Use either metric or US units.
- 4
Choose your activity level
Select the option that best matches your normal weekly routine.
- 5
Select your goal
Use maintain, lose, or gain weight targets as a starting point.
- 6
Track and adjust
Use the result for 2-4 weeks, then adjust based on real progress.
The math
Calorie Calculator Formulas
This calculator estimates BMR first, then multiplies BMR by your activity factor to estimate daily maintenance calories.
Mifflin-St Jeor for men
W = weight in kg, H = height in cm, A = age in years.
Mifflin-St Jeor for women
This is the default formula used by many calorie calculators for healthy adults.
Total daily energy expenditure
TDEE is the estimated daily calorie target for maintaining current weight.
Activity factor
Activity Level Multipliers
Selecting an honest activity factor is critical. Overestimating your routine will result in an excessively high calorie target.
| Activity level | Typical routine | Factor |
|---|---|---|
| BMR | No exercise | 1.0 |
| Sedentary | Little or no exercise, mostly sitting | 1.2 |
| Lightly active | Light exercise 1-3 days/week | 1.375 |
| Moderate | Exercise 4-5 times/week | 1.465 |
| Active | Daily exercise or intense exercise 3-4 times/week | 1.55 |
| Very active | Hard exercise 6-7 days/week | 1.725 |
| Extra active | Very hard exercise, physical job, or intense training | 1.9 |
Example
Calorie Calculation Example
This example shows how BMR becomes a daily maintenance target.
| Step | Value |
|---|---|
| Example person | 30-year-old male, 75 kg, 175 cm, active routine |
| BMR formula | 10(75) + 6.25(175) - 5(30) + 5 = 1,698.75 |
| Activity step | 1,699 × 1.55 = 2,633 kcal/day |
| Goal adjustment | Use a moderate deficit for loss or surplus for gain, then track progress. |
Use cases
When to Use This Calorie Calculator
Use this calculator when you need a practical baseline for maintenance, fat loss, weight gain, or nutrition planning.
- Estimate maintenance calories
- Find the approximate intake needed to keep your current weight stable.
- Plan weight loss
- Create a moderate calorie deficit without relying on extreme cuts.
- Plan weight gain
- Set a controlled surplus for gradual weight or muscle gain.
- Understand BMR and TDEE
- Separate resting calorie burn from total daily calorie burn.
- Compare activity levels
- See how changing movement changes daily calorie needs.
- Start a nutrition plan
- Use the estimate as a baseline before personal tracking fine-tunes it.
Planning context
Deficit, Surplus, and Accuracy Limits
Your estimated calories are a starting point. The number becomes more useful once you compare it with real weight and performance trends.
- Calorie deficit
- Consuming fewer calories than your body uses supports weight loss. Avoid extreme calorie cuts because eating too little makes consistency and adequate nutrition harder.
- Calorie surplus
- Consuming more calories than your body uses supports weight gain. Focus on nutrient-dense foods instead of relying on heavily processed or sugary items.
- Formula limits
- No mathematical formula can measure metabolism perfectly. Real needs depend on muscle mass, body fat, non-exercise movement, hormones, stress, sleep, and medical conditions.
Next checks
Use Calories with Other Calculators
For a stronger plan, pair calorie targets with BMR, TDEE, macro, BMI, body fat, and ideal weight estimates.
Frequently Asked Questions
Most adults need between 1,600 and 3,000 calories per day depending on age, sex, height, weight, and activity level. Our Calorie Calculator estimates your maintenance calories using the Mifflin-St Jeor equation and an activity multiplier — the most widely recommended approach for healthy adults.
BMR (Basal Metabolic Rate) is the energy your body uses at complete rest. TDEE (Total Daily Energy Expenditure) is BMR plus the calories burned through movement, exercise, and digestion. TDEE is the number that matters for daily eating plans. See our BMR Calculator and TDEE Calculator for details.
A deficit of 500 calories per day typically produces about 1 lb (0.45 kg) of fat loss per week, since one pound of body fat stores roughly 3,500 calories. Larger deficits speed up loss but increase the chance of muscle loss, hunger, and rebound. Most experts recommend a 10–25 percent deficit below maintenance.
A surplus of 250–500 calories per day above maintenance is usually enough to gain about 0.5–1 lb (0.2–0.45 kg) per week, mostly as a mix of muscle and some fat when paired with resistance training and 1.6–2.2 g of protein per kg of body weight.
We use the Mifflin-St Jeor equation, which is the most accurate predictive formula for most healthy adults according to the American Dietetic Association. We then multiply BMR by an activity factor (1.2–1.9) to estimate TDEE.
Different calculators use different formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, etc.) and different activity multipliers. Variations of 100–300 calories per day are normal. The right number for you is whatever keeps your weight stable over 2–3 weeks, then adjust from there.
They produce a useful estimate — usually within 10 percent of measured energy expenditure for healthy adults. Track your weight over a few weeks and adjust your intake by 100–200 calories at a time to find your true maintenance number.
Medical note
Calorie Calculator Disclaimer
This Calorie Calculator estimates daily metabolic energy requirements utilizing established Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle math modeling.
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