How to Calculate Bmi and how is bmi calculated formula The Body Mass Index (BMI) measures the weight status of your body in relation to the fat. how to calculate bmi It is a simple tool that helps to figure out the amount of excess body fat and the associated risks of carrying this extra weight. how to calculate bmi formula can applied to both men and women. It is advisable to use ‘Body Mass Index’ along with ‘Waist to Hip Ratio’ to get a complete picture of your weight status.

Body mass index (BMI) is a person’s weight in kilograms divided by the square of height in meters. BMI is an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity.

BMI does not measure body fat directly, but BMI is moderately correlated with more direct measures of body fat. Furthermore, how to calculate bmi formula BMI appears to be as strongly correlated with various metabolic and disease outcome as are these more direct measures of body fatness

What is BMI?

A person’s Body-Mass Index, or BMI, helps them check whether they’re a healthy weight for their height. If a person weighs less or more than the recommended weight for their height, it could lead to health issues in the future. While BMI is not the only factor individuals should consider while working on their health and fitness, it is a good starting point.

To understand what your BMI is, you need to know your height and weight. You can then use an online BMI calculator to check your BMI, which will help you understand if you’re underweight, a healthy weight, overweight or obese. Or, you can measure your height in metres and weight in kilograms. Divide your weight by your height squared to calculate your BMI.

BMI Introduction

BMI is a measurement of a person’s leanness or corpulence based on their height and weight, and is intended to quantify tissue mass. It is widely used as a general indicator of whether a person has a healthy body weight for their height. Specifically, the value obtained from the calculation of BMI is used to categorize whether a person is underweight.

normal weight, overweight, or obese depending on what range the value falls between. These ranges of BMI vary based on factors such as region and age, and are sometimes further divided into subcategories such as severely underweight or very severely obese. Being overweight or underweight can have significant health effects, so while BMI is an imperfect measure of healthy body weight, it is a useful indicator of whether any additional testing or action is required. Refer to the table below to see the different categories based on BMI that are used by the calculator.

How to calculate Body Mass Index

Body Mass Index is a simple calculation using a person’s height and weight. The formula is BMI = kg/m² where kg is a person’s weight in kilograms and m² is their height in metres squared.

A BMI of 25.0 or more is overweight, while the healthy range is 18.5 to 24.9. BMI applies to most adults 18-65 years.

Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. View the BMI tables or use the tool below to compute yours.

Enter the Details
Ethnicity*	SelectAsianAfricanCaucasianHispanicOther population groups
Sex*	Male Female
Select your Age*	Select18192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899
Enter your Height *	cm   (or)
	4′5′6′ Feet   0″1″2″3″4″5″6″7″8″9″10″11″  Inches
Enter your Weight *	kglb (Pound)
* Required

BMI calculator may overestimate and underestimate for muscular body how to calculate bmi formula mass and athletic body respectively.

Body Mass Index

for BMI greater than 35, go to Table 2

To use the table, find the appropriate height in the left-hand column labeled Height. Move across to a given weight (in pounds). The number at the top of the column is the BMI at that height and weight.
Pounds have been rounded off.

BMI	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35
Height (inches)	Body Weight (pounds)
58	91	96	100	105	110	115	119	124	129	134	138	143	148	153	158	162	167
59	94	99	104	109	114	119	124	128	133	138	143	148	153	158	163	168	173
60	97	102	107	112	118	123	128	133	138	143	148	153	158	163	168	174	179
61	100	106	111	116	122	127	132	137	143	148	153	158	164	169	174	180	185
62	104	109	115	120	126	131	136	142	147	153	158	164	169	175	180	186	191
63	107	113	118	124	130	135	141	146	152	158	163	169	175	180	186	191	197
64	110	116	122	128	134	140	145	151	157	163	169	174	180	186	192	197	204
65	114	120	126	132	138	144	150	156	162	168	174	180	186	192	198	204	210
66	118	124	130	136	142	148	155	161	167	173	179	186	192	198	204	210	216
67	121	127	134	140	146	153	159	166	172	178	185	191	198	204	211	217	223
68	125	131	138	144	151	158	164	171	177	184	190	197	203	210	216	223	230
69	128	135	142	149	155	162	169	176	182	189	196	203	209	216	223	230	236
70	132	139	146	153	160	167	174	181	188	195	202	209	216	222	229	236	243
71	136	143	150	157	165	172	179	186	193	200	208	215	222	229	236	243	250
72	140	147	154	162	169	177	184	191	199	206	213	221	228	235	242	250	258
73	144	151	159	166	174	182	189	197	204	212	219	227	235	242	250	257	265
74	148	155	163	171	179	186	194	202	210	218	225	233	241	249	256	264	272
75	152	160	168	176	184	192	200	208	216	224	232	240	248	256	264	272	279
76	156	164	172	180	189	197	205	213	221	230	238	246	254	263	271	279	287

How is BMI interpreted for adults?

For adults 20 years old and older, BMI is interpreted using standard weight status categories. how to calculate bmi formula These categories are the same for men and women of all body types and ages.

For example, here are the weight ranges, the corresponding BMI ranges, and the weight status categories for a person who is 5′ 9″.

For children and teens, the interpretation of BMI depends upon age and sex. For more information about interpretation for children and teens, read – What is a BMI percentile and how is it interpreted?

Is BMI interpreted the same way for children and teens as it is for adults?

BMI is interpreted differently for children and teens, even though it is calculated using the same formula as adult BMI. Children and teen’s BMI need to be age and sex-specific because the amount of body fat changes with age and the amount of body fat differs between girls and boys. how to calculate bmi The CDC BMI-for-age growth charts take into account these differences and visually show BMI as a percentile ranking. These percentiles were determined using representative data of the US population of 2- to 19-year-olds that was collected in various surveys from 1963-65 to 1988-94¹¹.

Obesity among 2- to 19-year-olds is defined as a BMI at or above the 95^th percentile of children of the same age and sex in this 1963 to 1994 reference population. how to calculated bmi formula  For example, a 10-year-old boy of average height (56 inches) who weighs 102 pounds would have a BMI of 22.9 kg/m². This would place the boy in the 95^th percentile for BMI – meaning that his BMI is greater than that of 95% of similarly aged boys in this reference population – and he would be considered to have obesity.

For more information and to access the CDC Growth Charts

For adults, the interpretation of BMI does not depend on sex or age. Read more about interpreting adult BMI.

Who shouldn’t use a BMI calculator

BMI is not used for muscle builders, long distance athletes, pregnant women, the elderly or young children. This is because BMI does not take into account whether the weight is carried as muscle or fat, just the number.

Those with a higher muscle mass, such as athletes, may have a high BMI but not be at greater health risk. how to calculate bmi Those with a lower muscle mass, how to calculate bmi formula such as children who have not completed their growth or the elderly who may be losing some muscle mass may have a lower BMI. During pregnancy and lactation, a woman’s body composition changes, so using BMI is not appropriate.

BMI table for adults

This is the World Health Organization’s (WHO) recommended body weight based on BMI values for adults. It is used for both men and women, age 18 or older.

Category	BMI range – kg/m2
Severe Thinness	< 16
Moderate Thinness	16 – 17
Mild Thinness	17 – 18.5
Normal	18.5 – 25
Overweight	25 – 30
Obese Class I	30 – 35
Obese Class II	35 – 40
Obese Class III	> 40

BMI chart for adults

This is a graph of BMI categories based on the World Health Organization data. how to calculate bmi formula. The dashed lines represent subdivisions within a major categorization.

BMI table for children and teens, age 2-20

The Centers for Disease Control and Prevention (CDC) recommends BMI categorization for children and teens between age 2 and 20.

Category	Percentile Range
Underweight	<5%
Healthy weight	5% – 85%
At risk of overweight	85% – 95%
Overweight	>95%

BMI chart for children and teens, age 2-20

The Centers for Disease Control and Prevention (CDC) BMI-for-age percentiles growth charts.

Chart for boys
Chart for girls

Risks associated with being overweight

Being overweight increases the risk of a number of serious diseases and health conditions. Below is a list of said risks, how to calculated bmi formula according to the Centers for Disease Control and Prevention (CDC):

• High blood pressure
• Higher levels of LDL cholesterol, which is widely considered “bad cholesterol,” lower levels of HDL cholesterol, considered to be good cholesterol in moderation, and high levels of triglycerides
• Type II diabetes
• Coronary heart disease
• Stroke
• Gallbladder disease
• Osteoarthritis, a type of joint disease caused by breakdown of joint cartilage
• Sleep apnea and breathing problems
• Certain cancers (endometrial, breast, colon, kidney, gallbladder, liver)
• Low quality of life
• Mental illnesses such as clinical depression, anxiety, and others
• Body pains and difficulty with certain physical functions
• Generally, an increased risk of mortality compared to those with a healthy BMI

As can be seen from the list above, there are numerous negative, in some cases fatal, outcomes that may result from being overweight. how to calculated bmi formula Generally, a person should try to maintain a BMI below 25 kg/m², but ideally should consult their doctor to determine whether or not they need to make any changes to their lifestyle in order to be healthier.

Risks associated with being underweight

Being underweight has its own associated risks, listed below:

• Malnutrition, vitamin deficiencies, anemia (lowered ability to carry blood vessels)
• Osteoporosis, a disease that causes bone weakness, increasing the risk of breaking a bone
• A decrease in immune function
• Growth and development issues, particularly in children and teenagers
• Possible reproductive issues for women due to hormonal imbalances that can disrupt the menstrual cycle. Underweight women also have a higher chance of miscarriage in the first trimester
• Potential complications as a result of surgery
• Generally, an increased risk of mortality compared to those with a healthy BMI

how to calculate bmi In some cases, being underweight can be a sign of some underlying condition or disease such as anorexia nervosa, how to calculated bmi formula which has its own risks. Consult your doctor if you think you or someone you know is underweight, particularly if the reason for being underweight does not seem obvious.

Limitations of BMI

Although BMI is a widely used and useful indicator of healthy body weight, it does have its limitations. BMI is only an estimate that cannot take body composition into account. Due to a wide variety of body types as well as distribution of muscle, bone mass, and fat, BMI should be considered along with other measurements rather than being used as the sole method for determining a person’s healthy body weight.

In adults:

BMI cannot be fully accurate because it is a measure of excess body weight, rather than excess body fat. how to calculate bmi BMI is further influenced by factors such as age, sex, ethnicity, muscle mass, and body fat, and activity level, among others. how to calculate bmi in kg For example, an older person who is considered a healthy weight.

But is completely inactive in their daily life may have significant amounts of excess body fat even though they are not heavy. how to calculated bmi formula  This would be considered unhealthy, while a younger person with higher muscle composition of the same BMI would be considered healthy. In athletes, particularly bodybuilders who would be considered overweight due to muscle being heavier than fat, it is entirely possible that they are actually at a healthy weight for their body composition. Generally, according to the CDC:

• Older adults tend to have more body fat than younger adults with the same BMI.
• Women tend to have more body fat than men for an equivalent BMI.
• Muscular individuals and highly trained athletes may have higher BMIs due to large muscle mass.

In children and adolescents:

The same factors that limit the efficacy of BMI for adults can also apply to children and adolescents. Additionally, height and level of sexual maturation can influence BMI and body fat among children. how to calculate bmi  BMI is a better indicator of excess body fat for obese children than it is for overweight children, whose BMI could be a result of increased levels of either fat or fat-free mass (all body components except for fat, which includes water, organs, muscle, etc.). In thin children, the difference in BMI can also be due to fat-free mass.

how to calculated bmi formula  That being said, BMI is fairly indicative of body fat for 90-95% of the population, and can effectively be used along with other measures to help determine an individual’s healthy body weight.

BMI formula

Below are the equations used for calculating BMI in the International System of Units (SI) and the US customary system (USC) using a 5’10”, 160-pound individual as an example:

USC Units: BMI = 703 × mass (lbs) height2 (in) = 703 × 160 702 = 22.96 kg m2 SI, Metric Units: BMI = mass (kg) height2 (m)  = 72.57 1.782  = 22.90 kg m2

Ponderal Index

The Ponderal Index (PI) is similar to BMI in that it measures the leanness or corpulence of a person based on their height and weight. how to calculate bmi The main difference between the PI and BMI is the cubing rather than squaring of the height in the formula (provided below). how to calculate bmi in kg While BMI can be a useful tool when considering large populations, it is not reliable for determining leanness or corpulence in individuals.

Although the PI suffers from similar considerations, the PI is more reliable for use with very tall or short individuals, while BMI tends to record uncharacteristically high or low body fat levels for those on the extreme ends of the height and weight spectrum. Below is the equation for computing the PI of an individual using USC, again using a 5’10”, 160-pound individual as an example:

USC Units: PI = height (in) ∛mass (lbs)  = 70 ∛160  = 12.89 in ∛lbs SI, Metric Units: PI = mass (kg) height3 (m)  = 72.57 1.783  = 12.87 kg m3

 

how to calculated bmi formula of a person