BMI Chart for Children by Age: Boys and Girls Weight

BMI Chart for Children by Age – Boys and Girls – Kids BMI Calculator.

Study this kids’ BMI (Body Mass Index) chart according to age, and learn when a child is obese by comparing to the BMI norms and percentiles for that age.

What Is BMI?

Body Mass Index (BMI) is a formula that calculates body fat based on someone’s height and weight. You can use a BMI calculator, like the one from KidsHealth mentioned below, to figure out your BMI. However, it’s also crucial to discuss these results with a doctor to fully understand what they mean.

Overview

Tracking BMI.

From age 2, doctors will check your child’s BMI during all routine checkups. Because children’s BMI varies as they grow, doctors use gender-specific growth charts to track these changes over time. This helps to monitor whether a child is growing appropriately.

Although BMI isn’t a flawless indicator of body fat, it does help identify whether a child is gaining weight too quickly or too slowly.

Understanding BMI Results.

BMI percentiles compare a child’s weight to others of the same age and gender. For example, a BMI in the 60th percentile means that 60% of children of the same age and gender have a lower BMI. It’s important to note that a high BMI can be due to a large body frame or significant muscle mass, not just excess fat. Conversely, a child with a small frame might have a normal BMI but still carry too much body fat.

BMI becomes less reliable during puberty, a time when children can gain weight rapidly. Discussing these changes with a doctor can clarify whether the weight gain is a normal part of growing up or a reason for concern.

BMI Categories:

Underweight: BMI below the 5th percentile for age, gender, and height.
Healthy weight: BMI from the 5th to less than the 85th percentile for age, gender, and height.
Overweight: BMI at or above the 85th percentile but below the 95th percentile for age, gender, and height.
Obese: BMI at or above the 95th percentile for age, gender, and height.

It’s better to view BMI trends over time rather than focusing on single measurements, which can be misleading.

When is a Child Obese according to the BMI Index?

A child is considered obese according to BMI (Body Mass Index) when their BMI is at or above the 95th percentile for children of the same age and geder. This categorization means that compared to other children in their age group, their BMI is higher than 95% of their peers.

BMI is used as a screening tool, not a diagnostic tool, and while it provides a quick measure of body fat based on height and weight, it doesn’t directly measure body fat percentage. Therefore, a high BMI can indicate high levels of body fat but could also be a result of high muscle mass or large body frame. This is why further assessments by a healthcare provider may be necessary to determine if excess fat is a health risk.

BMI Chart for Children by Age – Boys.

Please have a look at this BMI chart for kids by age, for boys, to understand normal BMI ranges for children at each age. Pay special attention to the 90th and 95th percentile to determine if your child is considered obese. Every BMI value coloured in green colours is above the 95th percentile and therefore considered in the obese range.

BMI Chart for Children by Age – Girls.

Please have a look at this BMI chart for children by age, for girls, to understand normal the BMI ranges for girls at each age. Pay special attention to the 90th and 95th percentile to determine if your child is considered obese. Every BMI value coloured in yellow is above the 95th percentile and therefore considered in the obese range.

BMI Chart for children Kids by Age percentiles Girls

How to Calculate Child’s BMI.

Measure the Weight: Weigh the child on a scale and record the weight in kilograms or pounds.
Measure the Height: Measure the height using a stadiometer, making sure the child stands straight with feet together. Record the height in meters or inches.
Calculate BMI: Use the weight and height measurements in the above formula to calculate BMI.
- If you are using kilograms and meters: $(m))2\text{BMI} = \frac{\text{weight (kg)}}{(\text{height (m)})^2}$
- If you are using pounds and inches: $(in))2\text{BMI} = \frac{\text{weight (lbs)} \times 703}{(\text{height (in)})^2}$

Simplified, you can also use this chart to calculate you childs’ BMI. Measure your child’s height and weight (with their shoes and heavy clothes off), and then calculate your kids’ BMI with this formula:

Body-Mass Index Formula (BMI Calculator)
Method	Example
1.Multiply their weight (in pounds) by 703	184 × 703 = (A) 129,352
2. Multiply their height (in inches) by itself	69 × 69 = (B) 4,761
3. Divide (A) by (B)	129,352 ÷ 4,761 = 27.2 (BMI Score)

What is the Normal Weight for a Girl, According to Age?

These are the average, normal weight ranges, 25th to 75th percentile for each age for girls. These ranges make up 50 percent of the girls. To be outside this range can be perfectly normal and healthy. Generally, girls in the 95th percentile are considered obese.

How Much Should a 1 Year Old Girl Weigh? (Normal, Average Weight)

A 1-year-old girl typically weighs between 18.4 – 22.4 pounds (8.3 – 10.2 kg) based on the 25th to 75th percentile range.

How Much Should a 2 Year Old Girl Weigh? (Normal, Average Weight)

A 2-year-old girl typically weighs between 22.8 – 28.4 pounds (10.3 – 12.9 kg).

How Much Should a 3 Year Old Girl Weigh? (Normal, Average Weight)

A 3-year-old girl typically weighs between 26.2 – 32.7 pounds (11.9 – 14.8 kg).

How Much Should a 4 Year Old Girl Weigh? (Normal, Average Weight)

A 4-year-old girl typically weighs between 30.0 – 36.9 pounds (13.6 – 16.7 kg).

How Much Should a 5 Year Old Girl Weigh? (Normal, Average Weight)

A 5-year-old girl typically weighs between 34.0 – 42.3 pounds (15.4 – 19.2 kg).

How Much Should a 6 Year Old Girl Weigh? (Normal, Average Weight)

A 6-year-old girl typically weighs between 38.2 – 48.0 pounds (17.3 – 21.8 kg).

How Much Should a 7 Year Old Girl Weigh? (Normal, Average Weight)

A 7-year-old girl typically weighs between 43.0 – 54.3 pounds (19.5 – 24.6 kg).

How Much Should an 8 Year Old Girl Weigh? (Normal, Average Weight)

An 8-year-old girl typically weighs between 47.9 – 61.4 pounds (21.7 – 27.9 kg).

How Much Should a 9 Year Old Girl Weigh? (Normal, Average Weight)

A 9-year-old girl typically weighs between 52.6 – 69.0 pounds (23.9 – 31.3 kg).

How Much Should a 10 Year Old Girl Weigh? (Normal, Average Weight)

A 10-year-old girl typically weighs between 57.9 – 77.4 pounds (26.3 – 35.1 kg).

How Much Should an 11 Year Old Girl Weigh? (Normal, Average Weight)

An 11-year-old girl typically weighs between 63.6 – 86.5 pounds (28.8 – 39.2 kg).

How Much Should a 12 Year Old Girl Weigh? (Normal, Average Weight)

A 12-year-old girl typically weighs between 69.9 – 96.5 pounds (31.7 – 43.8 kg).

How Much Should a 13 Year Old Girl Weigh? (Normal, Average Weight)

A 13-year-old girl typically weighs between 77.0 – 108.5 pounds (34.9 – 49.2 kg).

How Much Should a 14 Year Old Girl Weigh? (Normal, Average Weight)

A 14-year-old girl typically weighs between 83.6 – 119.5 pounds (37.9 – 54.2 kg).

How Much Should a 15 Year Old Girl Weigh? (Normal, Average Weight)

A 15-year-old girl typically weighs between 88.5 – 127.9 pounds (40.1 – 58.0 kg).

How Much Should a 16 Year Old Girl Weigh? (Normal, Average Weight)

A 16-year-old girl typically weighs between 92.0 – 133.2 pounds (41.7 – 60.4 kg).

How Much Should a 17 Year Old Girl Weigh? (Normal, Average Weight)

A 17-year-old girl typically weighs between 94.6 – 136.3 pounds (42.9 – 61.8 kg).

How Much Should an 18 Year Old Girl Weigh? (Normal, Average Weight)

An 18-year-old girl typically weighs between 95.9 – 137.9 pounds (43.5 – 62.6 kg).

What is the Normal Weight for a Boy, According to Age?

These are the average, normal weight ranges, 25th to 75th percentile for each age for boys. These ranges make up 50 percent of the boys. To be outside this range can be perfectly normal and healthy. Generally, boys in the 95th percentile are considered obese.

How Much Should a 1 Year Old Boy Weigh? (Normal, Average Weight)

A 1-year-old boy typically weighs between 20.6 – 24.5 pounds (9.3 – 11.1 kg).

How Much Should a 2 Year Old Boy Weigh? (Normal, Average Weight)

A 2-year-old boy typically weighs between 25.5 – 30.6 pounds (11.6 – 13.9 kg).

How Much Should a 3 Year Old Boy Weigh? (Normal, Average Weight)

A 3-year-old boy typically weighs between 29.3 – 34.9 pounds (13.3 – 15.8 kg).

How Much Should a 4 Year Old Boy Weigh? (Normal, Average Weight)

A 4-year-old boy typically weighs between 33.2 – 39.1 pounds (15.1 – 17.7 kg).

How Much Should a 5 Year Old Boy Weigh? (Normal, Average Weight)

A 5-year-old boy typically weighs between 36.9 – 44.3 pounds (16.7 – 20.1 kg).

How Much Should a 6 Year Old Boy Weigh? (Normal, Average Weight)

A 6-year-old boy typically weighs between 40.8 – 49.6 pounds (18.5 – 22.5 kg).

How Much Should a 7 Year Old Boy Weigh? (Normal, Average Weight)

A 7-year-old boy typically weighs between 44.5 – 55.1 pounds (20.2 – 25.0 kg).

How Much Should an 8 Year Old Boy Weigh? (Normal, Average Weight)

An 8-year-old boy typically weighs between 48.5 – 61.2 pounds (22.0 – 27.8 kg).

How Much Should a 9 Year Old Boy Weigh? (Normal, Average Weight)

A 9-year-old boy typically weighs between 52.5 – 67.9 pounds (23.8 – 30.8 kg).

How Much Should a 10 Year Old Boy Weigh? (Normal, Average Weight)

A 10-year-old boy typically weighs between 56.7 – 75.4 pounds (25.7 – 34.2 kg).

How Much Should an 11 Year Old Boy Weigh? (Normal, Average Weight)

An 11-year-old boy typically weighs between 61.4 – 84.3 pounds (27.9 – 38.2 kg).

How Much Should a 12 Year Old Boy Weigh? (Normal, Average Weight)

A 12-year-old boy typically weighs between 66.9 – 94.1 pounds (30.3 – 42.7 kg).

How Much Should a 13 Year Old Boy Weigh? (Normal, Average Weight)

A 13-year-old boy typically weighs between 72.3 – 104.7 pounds (32.8 – 47.5 kg).

How Much Should a 14 Year Old Boy Weigh? (Normal, Average Weight)

A 14-year-old boy typically weighs between 77.6 – 114.9 pounds (35.2 – 52.1 kg).

How Much Should a 15 Year Old Boy Weigh? (Normal, Average Weight)

A 15-year-old boy typically weighs between 82.5 – 124.1 pounds (37.4 – 56.3 kg).

How Much Should a 16 Year Old Boy Weigh? (Normal, Average Weight)

A 16-year-old boy typically weighs between 87.1 – 132.4 pounds (39.5 – 60.0 kg).

How Much Should a 17 Year Old Boy Weigh? (Normal, Average Weight)

A 17-year-old boy typically weighs between 90.6 – 139.0 pounds (41.1 – 63.1 kg).

How Much Should an 18 Year Old Boy Weigh? (Normal, Average Weight)

An 18-year-old boy typically weighs between 92.8 – 142.9 pounds (42.1 – 64.8 kg).

What to do if my Child is Obese (per BMI)?

If your child is categorized as obese based on their Body Mass Index (BMI), here are some practical steps you can take to help them achieve a healthier weight:

Consult a Pediatrician: It’s important to start with a medical evaluation. A pediatrician can confirm the BMI calculations, evaluate your child’s overall health, and check for any possible medical reasons for the obesity.
Develop a Plan with a Dietitian: A registered dietitian can help create a balanced eating plan tailored to your child’s nutritional needs. This plan will focus on whole, minimally processed foods, and will consider the appropriate caloric intake for weight management and growth.
Increase Physical Activity: Encourage activities that are enjoyable and age-appropriate. The goal is to get at least 60 minutes of physical activity each day, which can include play, sports, or simply walking or biking.
Educate on Healthy Choices: Teach your child about nutrition and the benefits of eating fruits, vegetables, lean proteins, and whole grains. Encourage them to make healthy choices and involve them in meal planning and preparation. Simple choices, like changing from full sugar cola to diet cola, or fruit juices without added sugar can make a big difference in daily calorie consumption. Also, consider replacing calorie snacks with low-calorie snacks, such as bananas, apple, cherry or grape tomatoes or even non-sweetened popcorn.
Set Realistic Goals: Set achievable and realistic weight management goals with your healthcare provider. It’s important that goals are supportive and not punitive.
Limit Screen Time: Reducing time spent on sedentary activities like watching TV or playing video games can help. Encourage more active pastimes.
Create a Supportive Environment: Everyone in the household should adopt healthier eating habits and activity levels to support the child’s health goals.
Monitor Progress: Regular follow-ups with healthcare providers can help monitor your child’s progress and adjust the plan as needed.
Medication: As a last resort, though Ozempic is not approved for use in pediatrics, Wegovy was recently approved by the FDA in 2022 as a weight loss treatment for children ages 12 and older.

Addressing childhood obesity is about gradual changes leading to sustainable health improvements. It’s crucial to approach the situation with understanding and support to encourage a positive mindset towards health and self-care in your child.