Child Daily Nutrition Calculator
Calculates estimated daily calorie needs for children and teens up to 18 with the Institute of Medicine Estimated Energy Requirement (EER) equations, using weight, height, age, sex, and activity level. Useful for parents and dietitians planning balanced meals for growing kids.
Last updated: September 2026
Formula below · 3 sources (dietaryguidelines.gov, healthychildren.org, aap.org) · Updated Sep 2026
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About this calculator
Weight in pounds is converted to kilograms (× 0.4536) and height in inches to metres (× 0.0254). It uses the Estimated Energy Requirement (EER) equations of the Institute of Medicine Dietary Reference Intakes (2005), which were built from doubly-labelled-water measurements in children and include an allowance for growth. Ages 3–8: boys EER = 88.5 − 61.9 × age + PA × (26.7 × weight kg + 903 × height m) + 20; girls EER = 135.3 − 30.8 × age + PA × (10 × weight kg + 934 × height m) + 20. Ages 9–18 use the same equations with + 25 instead of + 20. The physical-activity coefficient PA is 1.00 (sedentary), 1.13 (low active), 1.26 (active) or 1.42 (very active) for boys and 1.00, 1.16, 1.31 or 1.56 for girls; this calculator maps its four activity choices to those levels in order. Under 3 years it uses the infant equation EER = 89 × weight − 100 plus an energy-deposition allowance (175 kcal under 3 months, 56 at 3–5 months, 22 at 6–11 months, 20 at 1–2 years). Ages 19 and over return a message. Results are estimates for healthy, normally growing children; follow growth charts and a pediatrician's advice.
How to use
Example: a 10-year-old boy, 70 lbs, 52 inches tall, moderately active. Step 1 – Convert: 70 × 0.4536 = 31.75 kg; 52 × 0.0254 = 1.321 m. Step 2 – EER (boys 9–18, PA 1.26 for the moderate level): 88.5 − 61.9 × 10 + 1.26 × (26.7 × 31.75 + 903 × 1.321) + 25 = 88.5 − 619 + 1.26 × (847.7 + 1,192.7) + 25 ≈ 2,065 kcal/day. This is the estimated daily calorie target for this child.
Frequently asked questions
How many calories does a child need per day by age and activity level?
Calorie needs vary widely depending on a child's age, size, sex, and how active they are. A sedentary 6-year-old girl might need around 1,200 kcal/day, while a very active 12-year-old boy could need over 2,400 kcal/day. The IOM EER equations used here account for weight, height, age, sex, and activity level simultaneously to give a personalized estimate. These figures are starting points; growth spurts, illness, and sports seasons all cause natural fluctuations in appetite and need.
Which equation does this calculator use for children?
It uses the Institute of Medicine (2005) Estimated Energy Requirement equations, which were developed specifically for children and teens from doubly-labelled-water measurements and include an allowance for the energy cost of growth. Adult equations such as Harris-Benedict were never validated in children and typically underestimate their needs. For children under 3 it uses the IOM infant/toddler equation based on weight. A registered dietitian can help interpret the result in the context of a child's growth chart and individual health history.
Why do girls need fewer calories than boys of the same age and size?
On average, girls have a higher proportion of body fat and a lower proportion of lean muscle mass than boys of the same age and weight, and muscle tissue burns more calories at rest than fat tissue does; hormonal differences also play a role as puberty approaches. The IOM equations therefore have separate coefficients for boys and girls rather than a flat percentage reduction. Individual variation is substantial, so a child's actual needs are best assessed by tracking growth over time rather than relying on a single calculation.