Human body weight

There are a number of methods to estimate weight in children for circumstances (such as emergencies) when actual weight cannot be measured. Most involve a parent or health care provider guessing the child's weight through weight-estimation formulas. These formulas base their findings on the child's age and tape-based systems of weight estimation. Of the many formulas that have been used for estimating body weight, some include the Advanced Pediatric Life Support formula, the Leffler formula, and Theron formula.^[1] There are also several types of tape-based systems for estimating children's weight, with the best-known being the Broselow tape.^[2] The Broselow tape is based on length with weight read from the appropriate color area. Newer systems, such as the PAWPER tape, make use of a simple two-step process to estimate weight: the length-based weight estimation is modified according to the child's body habitus to increase the accuracy of the final weight prediction.^[3]

The Leffler formula is used for children 0–10 years of age.^[1] In those less than a year old, it is

${\displaystyle m={\tfrac {1}{2}}a_{m}+4}$

and for those 1–10 years old, it is

${\displaystyle m=2a_{y}+10}$

where m is the number of kilograms the child weighs and a_m and a_y respectively are the number of months or years old the child is.^[1]

The Theron formula is

${\displaystyle m=e^{0.175571a_{y}+2.197099}}$

where m and a_y are as above.^[1]

Body weight varies in small amounts throughout the day, as the amount of water in the body is not constant. It changes due to activities such as drinking, urinating, or exercise.^[4] Professional sports participants may deliberately dehydrate themselves to enter a lower weight class, a practice known as weight cutting.^[5]

Ideal body weight (IBW) was initially introduced by Ben J. Devine in 1974 to allow estimation of drug clearances in obese patients;^[6] researchers have since shown that the metabolism of certain drugs relates more to IBW than total body weight.^[7] The term was based on the use of insurance data that demonstrated the relative mortality for males and females according to different height-weight combinations.

The most common estimation of IBW is by the Devine formula; other models exist and have been noted to give similar results.^[7] Other methods used in estimating the ideal body weight are body mass index and the Hamwi method. The IBW is not the perfect fat measurement, as it does not show the fat or muscle percentage in one's body. For example, athletes' results may show that they are overweight when they are actually very fit and healthy. Machines like the dual-energy X-ray absorptiometry can accurately measure the percentage and weight of fat, muscle, and bone in a body.

The Devine formula for calculating ideal body weight in adults is as follows:^[7]

• Male ideal body weight = 50 kilograms (110 lb) + 0.9 kilograms (2.0 lb) × (height (cm) − 152)
• Female ideal body weight = 45.5 kilograms (100 lb) + 0.9 kilograms (2.0 lb) × (height (cm) − 152)

The Hamwi method is used to calculate the ideal body weight of the general adult:^[8]

• Male ideal body weight = 48 kilograms (106 lb) + 1.1 kilograms (2.4 lb) × (height (cm) − 152)
• Female ideal body weight = 45.4 kilograms (100 lb) + 0.9 kilograms (2.0 lb) × (height (cm) − 152)

Many disciplines in weightlifting or combat sports separate competitors into weight classes.

Ideal body weight, specifically the Devine formula, is used clinically for multiple reasons, most commonly in estimating renal function in drug dosing, and predicting pharmacokinetics in morbidly obese patients.^[9][10]

Data from 2005:

Country	Average male weight	Average female weight	Sample population / age range	Method	Year	Ref
Afghanistan	69.2 kg (152.6 lb)	62.6 kg (138.0 lb)	18–69	Measured	2018	[12]
Algeria	68.7 kg (151.5 lb)	65.1 kg (143.5 lb)	25–64	Measured	2005	[13]
Armenia	74.6 kg (164.5 lb)	66.4 kg (146.4 lb)	18–69	Measured	2016	[14]
Australia	87.0 kg (191.8 lb)	71.8 kg (158.3 lb)	18+	Measured	2018	[15]
Azerbaijan	72.1 kg (159.0 lb)	65.7 kg (144.8 lb)	16+	Measured	2005	[16]
Bangladesh	55.2 kg (121.7 lb)	49.8 kg (109.8 lb)	25+	Measured	2009–2010	[17]
Belarus	69 kg (152.1 lb)	56 kg (123.5 lb)	18+	Measured	2008	[18]
Belize	74.2 kg (163.6 lb)	70.5 kg (155.4 lb)	20+	Measured	2010	[19]
Benin	63.7 kg (140.4 lb)	60.9 kg (134.3 lb)	18–69	Measured	2015	[20]
Bhutan	63.2 kg (139.3 lb)	57.4 kg (126.5 lb)	18–69	Measured	2014	[21]
Botswana	63.6 kg (140.2 lb)	64.3 kg (141.8 lb)	15–69	Measured	2014	[22]
Brazil	72.7 kg (160.3 lb)	62.5 kg (137.8 lb)	20–74	Measured	2008–2009	[23]
Brunei	74.1 kg (163.4 lb)	62.9 kg (138.7 lb)	19+	Measured	2010–2011	[24]
Bulgaria	76.9 kg (169.5 lb)	69.1 kg (152.3 lb)	21–59	Self-reported	2021	[25]
Burkina Faso	65.2 kg (143.7 lb)	59.0 kg (130.1 lb)	25–64	Measured	2013	[26]
Cambodia	56.8 kg (125.2 lb)	50.8 kg (112.0 lb)	25–64	Measured	2010	[27]
Cameroon	68.3 kg (150.6 lb)	67.0 kg (147.7 lb)	15+	Measured	2003	[28]
Canada	84.6 kg (187 lb)	70.1 kg (155 lb)	18–79	Measured	2007–2009	[29]
Chile	77.3 kg (170.4 lb)	67.5 kg (148.8 lb)	15+	Measured	2009–2010	[30]
Costa Rica - San José	76.6 kg (168.9 lb)	64.9 kg (143.1 lb)	20+	Measured	2010	[31]
Czech Republic	92.1 kg (203.0 lb)	73.8 kg (162.7 lb)	25–64	Measured	2016–2017	[32]
Estonia	84.4 kg (186.1 lb)	71.2 kg (157.0 lb)	18+	Measured	2003–2010	[33]
France	77.1 kg (170 lb)	62.7 kg (138 lb)	15+	Measured	2005	[34]
Georgia	84.4 kg (186.1 lb)	73.6 kg (162.3 lb)	18–69	Measured	2016	[35]
Germany	85.9 kg (189.4 lb)	69.2 kg (152.6 lb)	18+	Self-reported	2021	[36]
India	65.0 kg (143.3 lb)	55.0 kg (121.3 lb)	16+	Measured	2020	[37]
Norway	86.6 kg (190.9 lb)	71.6 kg (157.9 lb)	18+	Self-reported	2020	[38]
Oman	74.9 kg (165.1 lb)	68.1 kg (150.1 lb)	18+	Measured	2017	[39]
Pakistan	66.0 kg (145.5 lb)	59.0 kg (130.1 lb)	18–69	Measured	2013–2014	[40]
Papua New Guinea	62.5 kg (137.8 lb)	56.8 kg (125.2 lb)	15–64	Measured	2007–2008	[41]
Qatar	84.6 kg (186.5 lb)	73.4 kg (161.8 lb)	18–64	Measured	2012	[42]
Russia	70.6 kg (155.6 lb)	60.2 kg (132.7 lb)	19+	Measured	2018	[43]
Rwanda	58.4 kg (128.7 lb)	55.9 kg (123.2 lb)	15–64	Measured	2012–2013	[44]
Saint Kitts and Nevis	84.5 kg (186.3 lb)	83.0 kg (183.0 lb)	25–64	Measured	2007–2008	[45]
Saudi Arabia	77.3 kg (170.4 lb)	71.7 kg (158.1 lb)	25–64	Measured	2005	[46]
Serbia	84.6 kg (186.5 lb)	70.0 kg (154.3 lb)	20+	Measured	2013	[47]
Sierra Leone	62.0 kg (136.7 lb)	59.0 kg (130.1 lb)	25–64	Measured	2009	[48]
Solomon Islands	75.3 kg (166.0 lb)	70.4 kg (155.2 lb)	25–64	Measured	2006	[49]
South Korea	73.34 kg (161.7 lb)	58.29 kg (128.5 lb)	18+	Measured	2019	[50]
Spain	82.4 kg (181.7 lb)	66.6 kg (146.8 lb)	18–64	Measured	2013	[51]
Sri Lanka	61.4 kg (135.4 lb)	54.6 kg (120.4 lb)	18–69	Measured	2014–2015	[52]
Sudan	65.4 kg (144.2 lb)	61.6 kg (135.8 lb)	18–69	Measured	2016	[53]
Sweden	81.9 kg (180.6 lb)	66.7 kg (147.0 lb)	16–84	Measured	2003–2004	[54]
Togo	63.2 kg (139.3 lb)	60.0 kg (132.3 lb)	15–64	Measured	2010	[55]
Tonga	99.4 kg (219.1 lb)	97.7 kg (215.4 lb)	25–64	Measured	2012	[56]
Trinidad and Tobago	76.7 kg (169.1 lb)	71.1 kg (156.7 lb)	15–64	Measured	2011	[57]
Turkey	78.0 kg (172.0 lb)	70.1 kg (154.5 lb)	15+	Measured	2017	[58]
Turkmenistan	76.6 kg (168.9 lb)	67.4 kg (148.6 lb)	18–69	Measured	2018	[59]
United Kingdom – England	85.4 kg (188.3 lb)	72.1 kg (159.0 lb)	16+	Measured	2019	[60]
United Kingdom – Wales	84.0 kg (185.2 lb)	69.0 kg (152.1 lb)	16+	Measured	2009	[61]
Ukraine	80.0 kg (176.4 lb)	71.0 kg (156.5 lb)	18+	Measured	2020	[62]
United States	90.6 kg (199.7 lb)	77.5 kg (170.9 lb)	20+	Measured	2015–2018	[63]

Researchers at the London School of Hygiene and Tropical Medicine published a study of average weights of adult humans in the journal BMC Public Health and at the United Nations conference Rio+20.^[64]