Calorie Calculator
Estimate your daily calorie needs based on your body details and activity level.
What This Calculator Does
This calorie calculator estimates your total daily energy expenditure (TDEE) — the number of calories your body burns each day. It uses your age, sex, weight, height, and activity level to produce a personalized estimate. This number serves as a starting point for weight management, whether your goal is maintenance, loss, or gain.
How Your Calorie Needs Are Estimated
The calculation is based on the Mifflin-St Jeor equation, one of the most widely validated formulas for estimating basal metabolic rate (BMR). BMR represents the calories your body needs at complete rest to maintain vital functions like breathing and circulation.
The formulas used are:
- For males: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- For females: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
Once BMR is calculated, it is multiplied by an activity factor to estimate total daily calorie needs. The activity levels range from sedentary (little to no exercise) to very active (intense exercise daily or physical labor).
Activity Level Multipliers
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise | 1.2 |
| Lightly active | Light exercise 1–3 days/week | 1.375 |
| Moderately active | Moderate exercise 3–5 days/week | 1.55 |
| Very active | Hard exercise 6–7 days/week | 1.725 |
| Extra active | Very hard exercise daily or physical job | 1.9 |
How to Use the Results
The estimated calorie number is your maintenance level. To adjust your weight, modify your intake relative to this number:
- To lose weight: Consume 300–500 fewer calories per day for gradual loss (about 0.5 kg per week).
- To gain weight: Consume 300–500 more calories per day for gradual gain.
- To maintain weight: Match your intake to the estimated number.
Individual results vary. Factors like muscle mass, hormonal differences, and metabolic adaptations can affect actual calorie needs.
Limitations to Keep in Mind
This estimate is a mathematical approximation, not a precise measurement. It does not account for:
- Body composition (muscle vs. fat ratio)
- Medical conditions affecting metabolism
- Medication side effects
- Hormonal fluctuations
- Individual metabolic variations
Use the result as a starting point and adjust based on real-world progress over several weeks.
Common Mistakes When Using Calorie Estimates
- Overestimating activity level: Choosing "very active" when you exercise moderately a few times a week leads to an inflated calorie target.
- Treating the number as exact: The result is an estimate. Expect to adjust based on actual weight changes.
- Ignoring portion sizes: Even with a target in mind, inaccurate tracking undermines results.
- Not recalculating after weight change: As you lose or gain weight, your calorie needs change. Recalculate every 5–10 kg.
Practical Use Cases
- Weight loss planning: Establish a starting calorie deficit for a structured diet plan.
- Muscle building: Determine a surplus to support muscle growth during resistance training.
- Maintenance after dieting: Find your new maintenance level after reaching a goal weight.
- General health awareness: Understand how your daily energy needs change with age and activity.
FAQ
Is this calorie calculator accurate?
It provides a reliable estimate based on the Mifflin-St Jeor equation, which has strong scientific support. However, individual metabolism varies. Use the result as a starting point and adjust based on your actual progress.
Should I eat exactly the number of calories shown?
Not necessarily. The number is your estimated maintenance level. Adjust it up or down based on your weight goal. Monitor your weight over 2–4 weeks and fine-tune as needed.
Why does the calculator ask for sex?
Men and women typically have different body compositions and hormonal profiles, which affect metabolic rate. The formula uses separate equations to account for these differences.
Do I need to recalculate if I lose weight?
Yes. As your weight changes, your calorie needs change too. Recalculate every 5–10 kg to keep your target accurate.
Can I use this for a child or teenager?
The Mifflin-St Jeor equation is designed for adults. Children and teenagers have different energy requirements due to growth and development. Consult a healthcare professional for pediatric needs.