What is BMI?

BMI is a calculation used to estimate a person's percent body fat. It is not a direct measurement of body fat, but it is simple to calculate and correlates well with actual body fat measurements.

The CDC and the American Academy of Pediatrics now recommend that BMI be used as a screening tool for children ages 2 and older.

How is BMI Calculated for Preschoolers?

BMI is calculated the same way for preschoolers and children as for adults - using height and weight. But you can't use adult healthy weight guidelines for children. For adults, standard ranges are used to find out if one is considered overweight, obese, or underweight. So, whether you are a 21-year-old male or a 65-year-old female, a BMI of 25 or greater means that you are considered overweight.

A child's BMI number, on the other hand, is compared to other children of the same age and gender. This is necessary because percent body fat changes as little bodies grow and develop. For example, a healthy two-year-old child would be expected to have a different percent body fat than a six-year-old. Also, gender affects BMI in children, unlike adults.

What Does My Preschooler's BMI Mean?

After your preschooler's BMI is calculated, you'll get a percentile, much like the height and weight percentiles you get at doctor's visits. The percentile tells how your child's BMI compares to other children of the same age and gender.

Underweight – BMI at less than 5th percentile

Healthy Weight – BMI at 5th – 85th percentile

At Risk of Overweight – BMI at 85th – 95th percentile

Overweight – BMI at 95th percentile or greater

Limitations of BMI

BMI is an estimate of body fat. Your child may be placed in an underweight or overweight category but still have a healthy body fat percent. A doctor can perform more direct measurements of body fat if necessary.

If you are concerned about your preschooler's weight, talk to your doctor or health practitioner about BMI, diet and exercise.

Calculate Your Preschooler's BMI

You will need accurate height and weight measurements. You can use measurements from the doctor's office or measure your preschooler at home.

Then go to the CDC BMI Calculator for Children and Teens. You will get a BMI number, percentile, and weight status for your preschooler.

Reference:

Centers for Disease Control and Prevention. BMI - Body Mass Index for Child and Teen. http://apps.nccd.cdc.gov/dnpabmi/Calculator.aspx

Helpful Tips for Parents

• Breakfast is the most reliably linked meal to cognitive performance in school-age children. Prioritize a protein- and fiber-rich breakfast every morning.

• Protein + fat + fiber at every meal stabilizes blood sugar and prevents the energy crashes that drive meltdowns, irritability, and inability to focus.

• Involve children in food preparation. Children who help prepare a meal are statistically more likely to eat it, even if it contains ingredients they previously rejected.

• Water is the ideal hydration for preschoolers. Milk (2–3 cups/day) is also appropriate. Sports drinks, soda, and excessive juice have no appropriate role in the preschool diet.

Frequently Asked Questions

Should I be counting calories for my preschooler?

Calorie counting for preschoolers is generally not recommended and can establish an unhealthy relationship with food. Preschoolers have a naturally functioning hunger-satiety regulation system (unless it has been overridden by pressure to eat or clean the plate). A preschooler who is growing on their own growth curve, has energy for normal activities, and is generally healthy is eating the right amount — regardless of whether you've counted calories. Discuss weight concerns with your pediatrician rather than independently restricting a preschooler's food intake.

How do I handle a preschooler who won't eat at mealtimes but is hungry 20 minutes later?

This pattern (refusing meals, requesting snacks immediately after) usually indicates one of three things: the meal's timing is wrong (not actually hungry yet), the meal's composition isn't appealing, or snacks are available too close to meals (reducing mealtime hunger). Maintain a predictable meal and snack schedule: 3 meals and 2–3 planned snacks 2–3 hours apart. Stick to the schedule — food is available at scheduled times only. The brief hunger between scheduled times is mild and temporary; it doesn't harm the child and it resets their appetite for the next meal.

Related reading: See also our meal planning guide and our breakfast ideas guide for more ideas on this topic.

🎓 Skills Your Child Will Develop

• 🥦 Healthy Food Knowledge — Learning about different foods, food groups, and what nutrients do in the body builds the food literacy that supports a lifetime of informed, health-conscious eating choices.
• 🌿 Where Food Comes From — Understanding that food grows from seeds, is harvested, and travels to the table connects children to the natural systems that sustain all human life — and measurably increases willingness to eat vegetables children have grown.
• 🔄 Trying New Things — Regular exposure to new foods in a positive, low-pressure context teaches children that trying something unfamiliar is safe and often rewarding — a disposition toward novelty that accelerates learning in all domains.
• 🌍 Environmental Awareness — Understanding where food comes from and how food choices affect the planet begins the environmental literacy that leads to conscious, sustainable food choices throughout life.

Have you wondered whether your preschooler is too heavy for his age or even too skinny? You may have used Body Mass Index (BMI) to see whether your own weight is healthy. This same tool can tell you whether your preschooler's weight is healthy or increases their health risk. To calculate a preschooler's BMI, you need accurate height and weight measurements, birth date, and gender.