Calorie Calculator
Calculate your daily caloric needs based on age, weight, height, gender, and activity level.
Last updated: June 2026
Example: 30-Year-Old Female, 5'6", 150 lbs, Moderately Active
Inputs
Results
What This Means
→ This example shows a moderately active woman whose body burns approximately 1,520 calories just to maintain basic functions (BMR).
→ With moderate activity (exercise 3–5 days per week), her total daily calorie burn is about 2,356 calories. This is the number she should eat to maintain current weight.
→ To lose weight at a healthy rate of about 1 lb per week, she should eat around 1,856 calories per day—a 500-calorie deficit.
→ Conversely, to build muscle while strength training, she should eat around 2,856 calories per day plus ensure adequate protein intake (~0.7–1g per lb of body weight, so about 105–150g protein daily).
Our calculators are built using established financial and scientific formulas. Finance tools follow standard amortization and compound interest principles. Health tools use WHO and NIH reference standards.
Last reviewed: June 2026
Learn more about our methodology →About the Calorie Calculator
What Are Calories and Why They Matter
A calorie is a unit of energy. When nutritionists talk about calories in food, they're actually referring to kilocalories (kcal)—the amount of energy your body can extract from food. Calories in food are burned by your body to fuel everything: breathing, thinking, moving, digesting, maintaining body temperature, and building muscle.
Understanding your daily calorie needs is the foundation of nutrition management. Whether your goal is weight loss, maintenance, or muscle gain, you need to know approximately how many calories your body requires daily.
Calculating Your Calorie Needs
Your daily calorie expenditure depends on several factors:
Basal Metabolic Rate (BMR) — Calories needed just to keep your body functioning at rest. This accounts for 60–75% of daily calories for sedentary people.
Activity level — Exercise and daily movement add significantly to calorie burn. Someone who exercises 5 days/week burns far more than someone sedentary.
Age and sex — Metabolism generally slows with age. Men typically have higher metabolic rates than women due to greater average muscle mass.
Body composition — Muscle tissue burns more calories at rest than fat tissue. Someone with high muscle mass burns more calories doing the same activities.
This calculator uses the widely-accepted Harris-Benedict or Mifflin-St Jeor equations to estimate your needs based on these factors.
Activity Level Multipliers
Your TDEE (Total Daily Energy Expenditure) is estimated by multiplying your BMR by an activity factor:
- Sedentary (little/no exercise): Multiply BMR by 1.2
- Lightly active (1–3 days/week exercise): Multiply BMR by 1.375
- Moderately active (3–5 days/week): Multiply BMR by 1.55
- Very active (6–7 days/week): Multiply BMR by 1.725
- Extremely active (intense daily exercise or physical job): Multiply BMR by 1.9
For example, if your BMR is 1,500 and you're moderately active, your TDEE ≈ 1,500 × 1.55 = 2,325 calories/day.
Using This Information for Health Goals
Weight maintenance: Eat approximately your TDEE in calories.
Weight loss: Eat 300–500 calories below TDEE to lose about 0.5–1 lb per week. Avoid extreme deficits, which slow metabolism and cause muscle loss.
Muscle gain: Eat 300–500 calories above TDEE while strength training. Muscle building requires both a calorie surplus and adequate protein.
Important caveat: Calorie estimates are approximate. Individual metabolism varies by genetics, hormones, and other factors. Adjust based on real results after 2–4 weeks.
Factors Affecting Calorie Needs
- Age — Metabolism slows ~2–8% per decade after age 30
- Body composition — More muscle = higher daily burn
- Hormones — Thyroid function, cortisol, estrogen, testosterone all affect metabolism
- Sleep — Poor sleep increases hunger hormones; good sleep supports metabolism
- Stress — Chronic stress can alter metabolism and appetite
- Genetics — Some people naturally have faster or slower metabolisms
Frequently Asked Questions
This calculator provides an estimate based on established equations. It's typically accurate within 10–20% for most people. Individual metabolism varies due to genetics, hormones, medical conditions, and other factors. Use this as a starting point, then adjust based on real-world results over 2–4 weeks.
How to Use This Calculator
- 1Enter your age in years.
- 2Enter your height in feet and inches, or select metric units for centimeters.
- 3Enter your current body weight in pounds or kilograms.
- 4Select your biological sex (calculator uses different equations for men and women).
- 5Select your typical activity level—be honest about how often you exercise.
- 6Click "Calculate Calories" to see your BMR and estimated daily calorie needs.
- 7Use the result as a starting point. Track food and weight for 2–4 weeks, then adjust up or down as needed.