Child Daily Calorie Needs Calculator
Estimates daily calorie needs for children aged 2–17 using the Mifflin-St Jeor equation adjusted for activity level. Use it when planning a child's diet or monitoring healthy growth.
About this calculator
This calculator uses the Mifflin-St Jeor Basal Metabolic Rate (BMR) formula adapted for children. For boys: BMR = 88.362 + (13.397 × weight_kg) + (4.799 × height_cm) − (5.677 × age). For girls: BMR = 447.593 + (9.247 × weight_kg) + (3.098 × height_cm) − (4.330 × age). The BMR represents calories needed at complete rest. This is then multiplied by an activity factor: 1.2 for sedentary, 1.375 for light activity, 1.55 for moderate activity, and 1.725 for very active children. The result gives Total Daily Energy Expenditure (TDEE) — the actual calories a child needs each day to maintain their current weight. These estimates are starting points; a pediatrician should guide dietary planning.
How to use
Suppose a 10-year-old boy weighs 32 kg, is 140 cm tall, and is moderately active. First calculate BMR: 88.362 + (13.397 × 32) + (4.799 × 140) − (5.677 × 10) = 88.362 + 428.704 + 671.86 − 56.77 = 1,132.156 kcal. Then multiply by the moderate activity factor: 1,132.156 × 1.55 ≈ 1,755 kcal/day. Enter age (10), weight (32 kg), height (140 cm), gender (male), and activity level (moderate) to get this result instantly.
Frequently asked questions
How many calories does a 10-year-old boy need per day?
A 10-year-old boy's daily calorie needs depend on his weight, height, and how active he is. Using the Mifflin-St Jeor formula, a moderately active 10-year-old boy of average size typically needs around 1,600–1,900 kcal per day. This calculator gives a personalized estimate based on his specific measurements. Always consult a pediatrician before making significant changes to a child's diet.
What activity level should I choose for my child in the calorie calculator?
Sedentary means little or no exercise beyond normal daily movement such as walking to school. Light activity covers 1–3 days per week of play or sports. Moderate activity applies to children active 3–5 days per week. Very active is appropriate for children who train or play sport 6–7 days per week or have physically demanding routines. When in doubt, choose the level that best matches a typical week rather than the child's most active day.
Why do boys and girls have different calorie formulas?
The Mifflin-St Jeor equation uses different constants for males and females because biological differences in muscle mass, fat distribution, and hormones affect basal metabolic rate. Boys generally have a higher proportion of lean muscle mass even during childhood, which burns more calories at rest. These sex-specific coefficients have been validated across large population studies. The difference becomes more pronounced during puberty when hormonal changes accelerate divergence in body composition.