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{{SI}}
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'''Body mass index''' ('''BMI''') is a widely used measure to estimate [[body fat]] based on an individual's [[height]] and [[weight]]. It serves as a simple screening tool to categorize individuals as underweight, normal weight, overweight, or obese.


Body mass index (BMI) is a measure of body fat based on a person's height and weight. It is commonly used as a screening tool to identify whether an individual is underweight, normal weight, overweight, or obese.
== Calculation of BMI ==
 
BMI is calculated using either the metric or imperial system.
==Calculation of BMI==
 
BMI is calculated by dividing a person's weight in kilograms by their height in meters squared. The formula for BMI is as follows:
 
BMI = weight (kg) / height^2 (m^2)
 
Alternatively, BMI can be calculated using pounds and inches with the following formula:
 
BMI = (weight (lb) / height^2 (in)) x 703
 
==Formula and Calculation== <!--T:6-->


===Metric system=== <!--T:7-->
=== Metric formula ===
BMI = weight (kg) / height (m)<sup>2</sup>


<!--T:8-->
Since height is often measured in [[centimeter|centimeters]], it should be converted to meters before using the formula.
With the system of weights and measures, the formula for BMI is weight in kilograms divided by height in meters square. Since height is usually measured in centimeters, divide height in centimeters by one hundred to get height in meters.


<!--T:9-->
Example:
Example: Weight = sixty eight kilogram, Height = a hundred sixty five cm (1.65 m)
* Weight = 68 kg
Calculation: sixty eight ÷ (1.65)2 = 24.98
* Height = 165 cm = 1.65 m
* Calculation: 68 / (1.65)<sup>2</sup> = 24.98


===Pounds and inches=== <!--T:10-->
=== Imperial formula ===
BMI = (weight (lb) / height (in)<sup>2</sup>) x 703


<!--T:11-->
Example:
Formula: weight (lb) / [height (in)]2 x 703
* Weight = 150 lbs
Calculate BMI by dividing weight in pounds (lbs) by height in inches (in) square and multiplying by a factor of 703.
* Height = 5'5" = 65 in
Example: Weight = one hundred fifty lbs, Height = 5\'5\" (65\")
* Calculation: (150 / (65)<sup>2</sup>) x 703 = 24.96
Calculation: [150 ÷ (65)2] x 703 = twenty four.96


[[File:BMI.jpg|left|600px]]
[[File:BMI.jpg|center|600px|thumb|BMI chart overview]]
==Interpretation of BMI for adults== <!--T:12-->
For adults twenty years previous and older, the following BMI categories are used. BMI is a useful measure of overweight and obesity. It is calculated from your height and weight. BMI is an estimate of body fat and a good gauge of your risk for diseases that can occur with more body fat. The higher your BMI, the higher your risk for certain diseases such as heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.


<!--T:13-->
== Interpretation of BMI for Adults ==
Although BMI can be used for most men and women, it does have some limits:
For adults aged 20 years and older, BMI is interpreted using standard weight status categories. It helps estimate [[health risk]]s related to excess body fat, such as:
* [[Heart disease]]
* [[Hypertension|High blood pressure]]
* [[Type 2 diabetes]]
* [[Gallstones]]
* [[Sleep apnea|Breathing problems]]
* Certain types of [[cancer]]


<!--T:14-->
== Limitations of BMI ==
It may overestimate body fat in athletes and others who have a muscular build.
While BMI is useful for general population screening, it has limitations:
It may underestimate body fat in older persons and others who have lost muscle.
* May overestimate body fat in individuals with a muscular build (e.g., athletes)
* May underestimate body fat in elderly individuals and others with low muscle mass


===BMI categories=== <!--T:15-->
== Adult BMI Categories ==
* Below 18.5: '''Underweight'''
* 18.5–24.9: '''Normal weight'''
* 25.0–29.9: '''[[Overweight]]'''
* 30.0–34.9: '''Class I [[Obesity]] (Mild)'''
* 35.0–39.9: '''Class II Obesity (Moderate)'''
* 40.0 and above: '''Class III Obesity (Severe or Morbid)'''


<!--T:16-->
== BMI for Children and Teens ==
* Body mass Index of below 18.5 is considered underweight
Although BMI is calculated the same way for children and teens as for adults, its interpretation differs. Age- and sex-specific percentiles are used to account for:
* Body mass index of 18.5 – 24.9 is considered normal
* Changes in body fat with age
* Body mass index of 25.0 – 29.9 is considered [[overweight]]
* Differences in body fat between boys and girls
* Body mass index of 30.0 - 34.9 is considered mild degree of [[obesity]]
* Body mass index of 35.0 - 39.9 is considered moderate degree of moderate [[obesity]]
* Body mass index of 30.0 - 34.9 is considered severe or morbid [[obesity]]


<!--T:17-->
These percentiles are based on [[growth charts]] and are used to determine whether a child or teen is underweight, normal weight, overweight, or obese.
'''Is BMI understood identical means for youngsters and youths because it is for adults?'''


<!--T:18-->
==Adult Body Mass Index Chart==
Although the BMI range is calculated identical means for youngsters and adults, the standards wont to interpret the that means of the BMI range for youngsters and youths are totally different from those used for adults. for youngsters and youths, BMI age- and sex-specific percentiles are used for 2 reasons:
The amount of body fat changes with age. The amount of body fat differs between women and boys. Because of these factors, the interpretation of BMI is each age- and sex-specific for youngsters and youths.
----
 
==Adult And Children Body Mass Index Calculators== <!--T:19-->
 
<!--T:20-->
* [http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/english_bmi_calculator/bmi_calculator.html Adult BMI Calculator CDC tool]
* [http://nccd.cdc.gov/dnpabmi/Calculator.aspx Children and teen BMI Calculator CDC tool]
 
==Adult Body Mass Index Chart== <!--T:21-->
{|
{|
| align="center" style="background:#f0f0f0;"|''' WEIGHT'''
| align="center" style="background:#f0f0f0;"|''' WEIGHT'''
Line 303: Line 290:
|}
|}


 
==Children BMI calculator==
<!--T:25-->
[[Category:obesity]]
'''Note: BMI values rounded to the nearest whole number. BMI categories based on CDC (Centers for Disease Control and Prevention) criteria.'''
 
<!--T:26-->
----
 
==Children BMI calculator== <!--T:27-->
The formulas used in children are different as their weight is based on growth charts and do not correspond to adult BMI scale numbers. Use an online childhood BMI calculators below.  
The formulas used in children are different as their weight is based on growth charts and do not correspond to adult BMI scale numbers. Use an online childhood BMI calculators below.  
* [http://apps.nccd.cdc.gov/dnpabmi/ CDC childhood BMI calculator]
* [http://apps.nccd.cdc.gov/dnpabmi/ CDC childhood BMI calculator]
== BMI Calculators ==
* [https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/english_bmi_calculator/bmi_calculator.html Adult BMI Calculator (CDC)]
* [https://nccd.cdc.gov/dnpabmi/Calculator.aspx Children and Teen BMI Calculator (CDC)]


==Online BMI Calculators== <!--T:28-->
== See also ==
While there are many BMI calculators, here are some BMI calculators you can use.
* [[Obesity]]
* [[Body fat percentage]]
* [[Waist-to-hip ratio]]
* [[Anthropometry]]


<!--T:29-->
{{Body measurements}}
* [http://www.w8md.com/81-w8md-patient-portal/76-w8md-bmi-calculator W8MD medical weight loss centers BMI calculator]
{{Health metrics}}
* [http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/english_bmi_calculator/bmi_calculator.html CDC BMI calculator]
* [http://www.nhlbi.nih.gov/guidelines/obesity/BMI/bmicalc.htm NHLBI BMI calculator online]
* [http:/www.philadelphiamedicalweightloss.com Philadelphia BMI calculator]
 
==Tips to [[lose weight|lose weight?]]== <!--T:30-->
* Understand the causes of [[weight gain]] and proven measures to lose weight.
{{w8md}}
{{w8md}}
 
[[Category:Obesity]]
==Also see==
[[Category:Epidemiology]]
* [https://w8md.com/wiki/Body_Mass_Index W8MD BMI]
[[Category:Medical assessment and evaluation]]
{{stub}}
[[Category:Health indices]]
{{DEFAULTSORT:Body Mass Index}}
[[Category:Belgian inventions]]
[[Category:Body shape]]
[[Category:Classification of obesity]]
[[Category:Human body weight]]
[[Category:Human height]]
[[Category:Mathematics in medicine]]
[[Category:Medical signs]]
[[Category:Ratios]]

Revision as of 14:09, 26 March 2025


Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's medical weight loss NYC, sleep center NYC
Philadelphia medical weight loss and Philadelphia sleep clinics
Body mass index (BMI) is a widely used measure to estimate body fat based on an individual's height and weight. It serves as a simple screening tool to categorize individuals as underweight, normal weight, overweight, or obese.

Calculation of BMI

BMI is calculated using either the metric or imperial system.

Metric formula

BMI = weight (kg) / height (m)2

Since height is often measured in centimeters, it should be converted to meters before using the formula.

Example:

  • Weight = 68 kg
  • Height = 165 cm = 1.65 m
  • Calculation: 68 / (1.65)2 = 24.98

Imperial formula

BMI = (weight (lb) / height (in)2) x 703

Example:

  • Weight = 150 lbs
  • Height = 5'5" = 65 in
  • Calculation: (150 / (65)2) x 703 = 24.96
BMI chart overview

Interpretation of BMI for Adults

For adults aged 20 years and older, BMI is interpreted using standard weight status categories. It helps estimate health risks related to excess body fat, such as:

Limitations of BMI

While BMI is useful for general population screening, it has limitations:

  • May overestimate body fat in individuals with a muscular build (e.g., athletes)
  • May underestimate body fat in elderly individuals and others with low muscle mass

Adult BMI Categories

  • Below 18.5: Underweight
  • 18.5–24.9: Normal weight
  • 25.0–29.9: Overweight
  • 30.0–34.9: Class I Obesity (Mild)
  • 35.0–39.9: Class II Obesity (Moderate)
  • 40.0 and above: Class III Obesity (Severe or Morbid)

BMI for Children and Teens

Although BMI is calculated the same way for children and teens as for adults, its interpretation differs. Age- and sex-specific percentiles are used to account for:

  • Changes in body fat with age
  • Differences in body fat between boys and girls

These percentiles are based on growth charts and are used to determine whether a child or teen is underweight, normal weight, overweight, or obese.

Adult Body Mass Index Chart

WEIGHT 4'8" 4'9" 4'10" 4'11" 5'0" 5'1" 5'2" 5'3" 5'4" 5'5" 5'6" 5'7" 5'8" 5'9" 5'10" 5'11" 6'0" 6'1" 6'2" 6'3" 6'4" 6'5"
lbs (kg) 142cm 147.32 149.86 152.4 154.94 157.48 160.02 162.56 165.1 167.64 170.18 172.72 175.26 177.8 180.34 182.88 185.42 187.96 190.5 193.04 195.58
260 (117.9) 58 56 54 53 51 49 48 46 45 43 42 41 40 38 37 36 35 34 33 32 32 31
255 (115.7) 57 55 53 51 50 48 47 45 44 42 41 40 39 38 37 36 35 34 33 32 31 30
250 (113.4) 56 54 52 50 49 47 46 44 43 42 40 39 38 37 36 35 34 33 32 31 30 30
245 (111.1) 55 53 51 49 48 46 45 43 42 41 40 38 37 36 35 34 33 32 31 31 30 29
240 (108.9) 54 52 50 48 47 45 44 43 41 40 39 38 36 35 34 33 33 32 31 30 29 28
235 (106.6) 53 51 49 47 46 44 43 42 40 39 38 37 36 35 34 33 32 31 30 29 29 28
230 (104.3) 52 50 48 46 45 43 42 41 39 38 37 36 35 34 33 32 31 30 30 29 28 27
225 (102.1) 50 49 47 45 44 43 41 40 39 37 36 35 34 33 32 31 31 30 29 28 27 27
220 (99.8) 49 48 46 44 43 42 40 39 38 37 36 34 33 32 32 31 30 29 28 27 27 26
215 (97.5) 48 47 45 43 42 41 39 38 37 36 35 34 33 32 31 30 29 28 28 27 26 25
210 (95.3) 47 45 44 42 41 40 38 37 36 35 34 33 32 31 30 29 28 28 27 26 26 25
205 (93.0) 46 44 43 41 40 39 37 36 35 34 33 32 31 30 29 29 28 27 26 26 25 24
200 (90.7) 45 43 42 40 39 38 37 35 34 33 32 31 30 30 29 28 27 26 26 25 24 24
195 (88.5) 44 42 41 39 38 37 36 35 33 32 31 31 30 29 28 27 26 26 25 24 24 23
190 (86.2) 43 41 40 38 37 36 35 34 33 32 31 30 29 28 27 26 26 25 24 24 23 23
185 (83.9) 41 40 39 37 36 35 34 33 32 31 30 29 28 27 27 26 25 24 24 23 23 22
180 (81.6) 40 39 38 36 35 34 33 32 31 30 29 28 27 27 26 25 24 24 23 22 22 21
175 (79.4) 39 38 37 35 34 33 32 31 30 29 28 27 27 26 25 24 24 23 22 22 21 21
170 (77.1) 38 37 36 34 33 32 31 30 29 28 27 27 26 25 24 24 23 22 22 21 21 20
165 (74.8) 37 36 34 33 32 31 30 29 28 27 27 26 25 24 24 23 22 22 21 21 20 20
160 (72.6) 36 35 33 32 31 30 29 28 27 27 26 25 24 24 23 22 22 21 21 20 19 19
155 (70.3) 35 34 32 31 30 29 28 27 27 26 25 24 24 23 22 22 21 20 20 19 19 18
150 (68.0) 34 32 31 30 29 28 27 27 26 25 24 23 23 22 22 21 20 20 19 19 18 18
145 (65.8) 33 31 30 29 28 27 27 26 25 24 23 23 22 21 21 20 20 19 19 18 18 17
140 (63.5) 31 30 29 28 27 26 26 25 24 23 23 22 21 21 20 20 19 18 18 17 17 17
135 (61.2) 30 29 28 27 26 26 25 24 23 22 22 21 21 20 19 19 18 18 17 17 16 16
130 (59.0) 29 28 27 26 25 25 24 23 22 22 21 20 20 19 19 18 18 17 17 16 16 15
125 (56.7) 28 27 26 25 24 24 23 22 21 21 20 20 19 18 18 17 17 16 16 16 15 15
120 (54.4) 27 26 25 24 23 23 22 21 21 20 19 19 18 18 17 17 16 16 15 15 15 14
115 (52.2) 26 25 24 23 22 22 21 20 20 19 19 18 17 17 16 16 16 15 15 14 14 14
110 (49.9) 25 24 23 22 21 21 20 19 19 18 18 17 17 16 16 15 15 15 14 14 13 13
105 (47.6) 24 23 22 21 21 20 19 19 18 17 17 16 16 16 15 15 14 14 13 13 13 12
100 (45.4) 22 22 21 20 20 19 18 18 17 17 16 16 15 15 14 14 14 13 13 12 12 12
95 (43.1) 21 21 20 19 19 18 17 17 16 16 15 15 14 14 14 13 13 13 12 12 12 11
90 (40.8) 20 19 19 18 18 17 16 16 15 15 15 14 14 13 13 13 12 12 12 11 11 11
85 (38.6) 19 18 18 17 17 16 16 15 15 14 14 13 13 13 12 12 12 11 11 11 10 10
80 (36.3) 18 17 17 16 16 15 15 14 14 13 13 13 12 12 11 11 11 11 10 10 10 9

Source: BRFSS survey data from CDC

Limitations of BMI

Although BMI is widely used as a screening tool for body fat, it has some limitations. BMI does not distinguish between fat and muscle, which can result in an inaccurate classification of body fat in athletes and individuals with a muscular build. Additionally, BMI does not take into account body composition or distribution of body fat, which can impact health outcomes. For example, visceral fat, which is located deep in the abdomen and surrounds organs, is associated with an increased risk of metabolic disorders such as Type 2 Diabetes and cardiovascular disease.

Usefulness of BMI

Despite its limitations, BMI remains a useful tool for population-level screening for overweight and obesity. It can be used to estimate the prevalence of overweight and obesity in a population and to track changes over time. BMI can also be used as a starting point for discussions between healthcare providers and patients about weight-related health risks and the need for lifestyle changes.

Distribution of body weight by percentage distribution adults - 2012

State: Underweight (bmi 12.0-18.4) Normal Weight (bmi 18.5-24.9) Overweight (bmi 25.0-29.9) Obese (bmi 30.0 - 99.8)
Nationwide (States, DC, and Territories) 1.8 34.2 35.8 28.1
Nationwide (States and DC) 1.8 34.2 35.8 27.6
Alabama 1.7 30.6 34.8 33.0
Alaska 0.9 34.4 39.1 25.7
Arizona 2.3 35.7 36.0 26.0
Arkansas 1.8 29.5 34.2 34.5
California 1.9 37.8 35.3 25.0
Colorado 2.3 42.0 35.2 20.5
Connecticut 1.7 36.1 36.7 25.6
Delaware 1.5 32.5 39.1 26.9
District of Columbia 2.2 46.0 30.0 21.9
Florida 1.5 36.4 36.9 25.2
Georgia 2.0 33.3 35.5 29.1
Guam 2.9 35.6 32.4 29.1
Hawaii 2.7 41.2 32.5 23.6
Idaho 1.8 35.7 35.8 26.8
Illinois 2.2 33.8 35.8 28.1
Indiana 1.7 32.8 34.1 31.4
Iowa 1.8 33.5 34.3 30.4
Kansas 2.0 32.4 35.7 29.9
Kentucky 2.0 31.1 35.6 31.3
Louisiana 1.9 28.5 34.8 34.7
Maine 1.6 34.3 35.8 28.4
Maryland 2.0 34.2 36.2 27.6
Massachusetts 2.1 39.2 35.9 22.9
Michigan 1.6 32.8 34.6 31.1
Minnesota 1.6 35.4 37.3 25.7
Mississippi 1.8 29.3 34.3 34.6
Missouri 1.9 32.4 36.2 29.6
Montana 1.5 37.1 37.0 24.3
Nebraska 1.7 33.3 36.4 28.6
Nevada 2.7 34.8 36.3 26.2
New Hampshire 1.4 36.5 34.8 27.3
New Jersey 1.9 36.5 37.0 24.6
New Mexico 2.2 35.0 35.7 27.1
New York 2.6 36.9 37.0 23.6
North Carolina 1.8 32.4 36.3 29.6
North Dakota 1.8 32.0 36.6 29.7
Ohio 1.7 33.0 35.2 30.1
Oklahoma 1.8 30.4 35.6 32.2
Oregon 1.7 37.2 33.8 27.3
Pennsylvania 1.7 33.3 35.9 29.1
Puerto Rico 2.1 31.7 37.8 28.4
Rhode Island 1.6 35.5 37.2 25.7
South Carolina 1.5 32.4 34.5 31.6
South Dakota 1.5 32.4 37.9 28.1
Tennessee 2.0 32.7 34.2 31.1
Texas 1.8 33.2 35.9 29.2
Utah 1.8 40.4 33.5 24.3
Vermont 1.7 38.0 36.6 23.7
Virginia 2.0 34.4 36.2 27.4
Washington 1.8 36.0 35.4 26.8
West Virginia 1.7 30.0 34.5 33.8
Wisconsin 1.8 31.8 36.8 29.7
Wyoming 1.5 35.1 38.7 24.6

Children BMI calculator

The formulas used in children are different as their weight is based on growth charts and do not correspond to adult BMI scale numbers. Use an online childhood BMI calculators below.

BMI Calculators

See also

Template:Body measurements Template:Health metrics

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