Kids Calorie Calculator: Daily Calories, Ages 1 to 17

Enter your child's age, sex, height, weight and how active they are, and we estimate their daily calories with the National Academies' 2023 energy equations. It covers ages 1 year 0 months to 17 years 11 months.

TL;DR

This calculator estimates daily calories for ages 1 to 17 using the National Academies' 2023 equations.
The number is an estimate for normal growth, not a weight-loss or weight-gain target.
Worried about weight, growth or eating? Talk with your child's pediatrician.

How the calculator works

You enter age in years and months, Girl or Boy, and height and weight in inches and pounds or centimeters and kilograms. Height is required.

For a growing child, the estimated energy requirement is the energy the body uses in a day plus the energy cost of growth (NASEM, Ch. 5). For ages 3 to 18, growth adds "merely 1 to 3 percent" on top.

Under 3: no activity question

For the youngest children the equations use age, sex, height and weight only, because activity varies so little at this age that it is not split into levels (NASEM, Ch. 5).

From 3: "How active?"

From age 3 the National Academies use separate equations for four activity levels, based on how active children of the same age and sex measure. Our three choices map to three of them:

Mostly calm uses "inactive": basic daily living.
Somewhere in between uses "low active": some extra walking and recreation.
Never stops moving uses "active": more of both.

We do not offer the fourth level, "very active." The report calls choosing the activity level "Perhaps the most challenging aspect of using the EER equations" and says a valid, reliable tool for it does not appear to exist (NASEM, Ch. 7). Pick the closest fit.

Why you see a range

The result shows one rounded number and a band 10% above and below it. That ±10% is our practical choice, not a figure from the National Academies. Their own statistical spread is wider (see the 15-year-old below). The calculator applies no goal; it shows the plain estimate.

Worked examples

We ran these three children through the calculator's code.

Child	Height, weight	Activity answer	Estimate	Range shown
3-year-old girl	38 in, 33 lb	Somewhere in between	about 1,104	994 to 1,214
8-year-old boy	52 in, 65 lb	Never stops moving	about 1,932	1,739 to 2,125
15-year-old boy who plays sports	67 in, 145 lb	Never stops moving	about 3,187	2,868 to 3,506

Our code also reproduces the report's own examples: 1,281 calories for a 2-year-old boy at 98 cm and 15.5 kg, and 3,190 for an active 15-year-old boy at 170 cm and 66 kg (NASEM, Ch. 7). For that teen, the report's 95% prediction interval is 2,684 to 3,696 calories, which shows how much real children can differ.

What the number is, and what it is not

The estimate is the energy needed to keep up current activity and body weight, with normal growth. The National Academies say plainly that the equations "do not predict energy requirements for those seeking to lose or gain weight" (NASEM, Ch. 7). The same equations are recommended for children of every BMI category (NASEM, Ch. 5).

So it is not an amount your child should eat, and not a line to stay under. Two children with identical inputs can need different amounts, which is why the report says "it is important to monitor body weight over time" (NASEM, Ch. 7).

Long-standing AAP guidance for parents of school-age children agrees: "There is rarely a reason for you to count calories for your children, since most youngsters control their intake quite well" (HealthyChildren.org).

Teens, growth spurts and sports

Appetite often surges around age 10 in girls and 12 in boys, ahead of the pubertal growth spurt, and "The body demands more calories during early adolescence than at any other time of life" (AAP, HealthyChildren.org). Teens who are big and tall, or physically active, still need more energy into late adolescence.

For young athletes, keep two things in mind:

Our top choice is "active," not "very active." For a median-size US 15-year-old boy, the National Academies list about 3,596 calories at the very active level (NASEM, Table 7-7), more than our sporty example above.
Heavy training can go beyond the equations. Elite athletes in heavy training often exceed what the equations cover and "would not meet their energy requirements" by eating the estimate, even at the very active level (NASEM, Ch. 7).

Too little fuel is a risk for young athletes. RED-S "happens when an athlete does not eat enough nutritious food to meet the energy needs of their sport and their growing body," and it can affect puberty (AAP, HealthyChildren.org). Calorie-limiting diets often lower training intensity and performance, and athletes who want to change weight should talk with their doctor (HealthyChildren.org).

When to talk to a pediatrician or dietitian

You are worried about your child's weight. "Talk with their health care provider" (CDC).
Your child may not be gaining enough weight, or is losing weight. The doctor looks at growth over time, and a dietitian may help find the best way to add calories (AAP, HealthyChildren.org). More in our guide to a toddler not gaining weight.
Your teen wants to go on a weight-loss diet. They "should first talk with a pediatrician" (AAP, HealthyChildren.org).
An athlete's growth changes, or eating starts to worry you. Pressure to gain or lose weight, strict food rules, feeling anxious or guilty about eating, or using diet pills or laxatives to manage weight are among the signs the AAP says may be a reason to talk with a health care provider (AAP, HealthyChildren.org). A RED-S care team may include a registered dietitian.

The same estimate in the Sito app

In Sito, this estimate is where each child's daily calorie range starts, shown alongside daily ranges and limits for other nutrients such as protein, fiber, added sugars, iron, calcium and vitamin D. There are no daily goals before the first birthday.

If a doctor or dietitian gave you a number, enter it under "Edit nutrition goals" and we use yours instead. For any weight concern, start with your child's doctor. More in our calorie tracker for kids guide.

The same estimate, every day

Sito starts each child's calorie range from this estimate and adds up what they ate, with protein, fiber, iron and calcium alongside.

Download on the App Store

Get it on Google Play

FAQ

How many calories does a toddler need?

For median-size US toddlers, the National Academies list about 821 calories a day for boys and 780 for girls at 12 to 14 months, and 1,058 and 1,011 at 24 to 26 months (NASEM, Ch. 7). Under 3, activity is not part of the equation. If your toddler needs more energy, see high-calorie foods for toddlers.

How many calories should a teenager eat?

It depends a lot on size and activity. For median-size US 15-year-olds, the reference numbers run from about 2,744 to 3,596 calories for boys and 2,082 to 2,720 for girls, inactive to very active (NASEM, Ch. 7). Teens in very heavy training can need more.

Is this calculator for weight loss?

No. The equations do not predict needs for losing or gaining weight (NASEM, Ch. 7). A 2011 AAP handout for young athletes says children ages 2 to 10 generally should not lose weight (HealthyChildren.org), and teens planning a weight-loss diet should first talk with a pediatrician (HealthyChildren.org). For any weight worry, start with your child's health care provider (CDC).

Sources

Sito is not a medical application, and this page is not medical advice. All sources accessed September 14, 2026.

A note from us: This article is for educational purposes and isn't medical advice. Sito is not a medical application and does not provide medical advice, diagnosis or treatment (our terms). Every child is different. For concerns about your child's growth, diet, or health, please talk to your pediatrician or a registered dietitian.

About the author: Berkay Yenilmez is the founder of Sito, the AI-powered kids nutrition tracker. We build our guidance on published National Academies, AAP and CDC references, the same sources linked above.

Kids Calorie Calculator: Daily Calories for Toddlers to Teens