A calorie calculator estimates how many calories your body needs each day based on factors such as age, sex, height, weight, and activity level. It is commonly used for weight loss, weight gain, or weight maintenance planning.
How calorie calculators work
Most calculators follow these steps:
- Calculate Basal Metabolic Rate (BMR)
- BMR is the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and body temperature.
- BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
- Estimate Total Daily Energy Expenditure (TDEE)
- Multiply your BMR by an activity factor:
- Adjust based on your goal
- Maintain weight: Eat approximately your TDEE.
- Lose weight: Consume about 300–500 fewer calories per day.
- Gain weight: Consume about 300–500 extra calories per day.
Example
A 30-year-old man:
- Weight: 70 kg
- Height: 175 cm
- Moderately active
BMR:
- (10 × 70) + (6.25 × 175) − (5 × 30) + 5
- = 1,649 calories/day
TDEE:
- 1,649 × 1.55 ≈ 2,556 calories/day
Recommendations:
- Maintenance: ~2,550 calories/day
- Weight loss: ~2,050–2,250 calories/day
- Weight gain: ~2,850–3,050 calories/day
Information needed for an accurate calculation
A calorie calculator typically requires:
- Age
- Sex
- Height
- Weight
- Activity level
- Goal (lose, maintain, or gain weight)
Limitations
- Estimates are averages and may not reflect your exact metabolism.
- Muscle mass, genetics, hormones, medications, and health conditions can affect calorie needs.
- Athletes, pregnant individuals, and people with certain medical conditions may need specialized guidance.
If you provide your:
- Age
- Sex
- Height
- Weight
- Activity level
- Goal (lose, maintain, or gain weight)
