Weight Norm for Height: How to Assess Normal Body Weight

Weight norm is not a single number from a table, but a range that suits a person with their height, age and build. Let's look at what height-weight indices show, where the boundaries of the norm come from, and when the number on the scale says less than it seems.

What is considered normal body weight

In medicine, normal body weight is the one at which weight corresponds to height and is not associated with an increased health risk. In practice, it is most often assessed through body mass index (BMI): the value allows an indirect judgment of whether a person's weight is insufficient, normal or excessive.

"Norm" does not equal "national average": a BMI exactly in the middle of statistical values among the population in most countries of the world is already considered overweight. The boundaries of the norm have changed over the past 30 years — until 1998 in the USA, a BMI up to 27.8 kg/m² was considered normal, later the upper limit was set at 25 kg/m². In Hong Kong and Japan, a BMI of 25 and above is considered obesity.

How weight and height relate: body mass index

BMI was proposed by the Belgian statistician Adolphe Quetelet in 1835. The formula is simple: weight in kilograms divided by height in meters squared. For 77 kg and 170 cm, BMI = 77 : (1.70 × 1.70) ≈ 26.64 kg/m².

• below 18.5 — underweight;
• 18.5–24.9 — normal;
• 25.0–29.9 — overweight;
• 30.0–39.9 — obesity;
• 40 and above — severe obesity and high risk.

Within obesity, three classes are distinguished: 30–35, 35–40 and 40 and above. Obesity strains the heart and is associated with arthritis of the knee and hip joints, heart disease, high blood pressure, sleep apnea, type 2 diabetes and varicose veins.

Normal weight for heights of 160, 165 and 175 cm

If we start from the BMI boundaries of 18.5–24.9, the following benchmarks emerge: height 160 cm — approximately 47–64 kg, 165 cm — about 50–68 kg, 175 cm — around 57–76 kg.

Other indices give different values. The Broca index is used for heights of 155–170 cm: weight = height minus 100, plus or minus 10%, that is, for 165 cm this is 58.5–71.5 kg. The Noorden index is calculated as height × 0.42, the Tatonya index — as height minus (100 + (height − 100) : 20). This is where the discrepancy in the tables that circulate on websites comes from.

Weight norm for women and men

The interpretation of BMI recommended by WHO does not take sex and age into account. At the same time, statistics from many countries show that BMI in men is on average higher than in women. For a more accurate assessment, the doctor looks not only at the number but also at waist circumference and the waist-to-hip ratio.

Fat distribution matters a lot: the risk of type 2 diabetes and cardiovascular diseases increases when there is more fat in the waist area rather than the hips. Body shape reflects health better than a single indicator.

Weight by age: what changes

BMI is usually higher in people of mature age than in the young and in older people. For people aged 65 and older, healthy ranges are different: a slightly elevated BMI may protect against bone thinning (osteoporosis). At the same time, an elderly person with a BMI in the normal range may have less muscle than a peer with a slight excess of weight.

For children, adult BMI calculators are not suitable: a child's weight is assessed separately, taking age into account and together with a doctor.

Limitations of tables and BMI: when to see a doctor

BMI is an approximate tool. In people with a large amount of muscle, it can be high without excess fat. The opposite also happens: among residents of Finland with a BMI normal by WHO criteria, at least 20% of men and at least 30% of women had elevated fat content — with a sedentary lifestyle, weight is provided by fat, not muscle.

BMI by itself does not predict health risk, but most experts consider a BMI of 30 and above unhealthy. One realistic idea for the week: calculate your BMI once and discuss the result with a doctor, not with a table from social media. The doctor will assess BMI, waist circumference and the waist-to-hip ratio, and if necessary prescribe examinations.

Weight itself and its changes are not a reason to call an ambulance. The numbers 103 and 112 are needed for life-threatening conditions — for example, if a stroke or heart attack is suspected.

This material is for reference: it helps to make sense of the numbers but does not replace a doctor's consultation — the final assessment of weight is given by a specialist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer