DokportTehty Suomessa

BMI calculator
Body mass index

Body mass index (BMI) shows whether your weight is in the healthy range for your height. Enter your height and weight — you get the result instantly, no sign-up needed.

The calculator runs in your browser. We do not store your height, weight or result.

cm
kg
26.4BMI
Overweight

Mild excess weight. The risk grows especially if fat has accumulated around the waist.

1518.525303540+
At your height of 172 cm, the healthy range (BMI 18.5–25) is about 55–74 kg.

The result is indicative and does not replace a doctor's assessment. BMI does not account for body composition, age or medical conditions.

Classification

BMI categories in adults

The classification follows the WHO standard and national obesity guidelines, and applies to adults aged 18–64.

BMICategory and what it means
below 18.5
UnderweightWeight is below the healthy range. Over time this can weaken immunity, bones and hormonal function.
18.5–24.9
Normal weightThe healthy target range for adults aged 18–64.
25.0–29.9
OverweightMild excess weight. The health risk depends a lot on where the fat sits and whether other risk factors are present.
30.0–34.9
ObesityThe risk of type 2 diabetes, high blood pressure and sleep apnoea is elevated.
35.0–39.9
Severe obesityThe health risk is clearly increased. Treatment is planned with a doctor.
40 or more
Morbid obesityThe risk is high. Treatment often includes medication or an assessment for surgery.
What BMI is

How body mass index is calculated

Body mass index (BMI) is weight divided by height squared. It is a simple way to estimate whether weight carries a health risk — which is why it is used both in healthcare and in population studies.

FormulaBMI = weight (kg) ÷ height (m)²Example: 72 kg and 172 cm → 72 ÷ (1.72 × 1.72) = 24.3

Measure your height without shoes and weigh yourself preferably in the morning in light clothing. A single weighing easily varies by 1–2 kilos, so follow the trend over months rather than days.

The adult classification is not used for children and adolescents. Under-18s are assessed with age- and sex-adjusted BMI — this calculator is intended for adults.

Scales and a measuring tape for tracking weight

Alongside BMI: waist circumference

Fat stored around the abdomen is more harmful to health than fat elsewhere in the body. Waist circumference is measured standing, midway between the lowest rib and the top of the hip bone, after breathing out.

Womenover 90 cmincreased risk
Menover 100 cmincreased risk
Limitations

When BMI is misleading

BMI cannot tell muscle, fat and fluid apart. In these situations, interpret the result with caution — or leave the interpretation to a professional.

High muscle mass

Muscle weighs more than fat. A strength athlete can have a BMI above 25 even with low body fat.

Older age

Over 65, muscle mass declines and a slightly higher BMI (around 23–29) is linked with better functional capacity.

Pregnancy and breastfeeding

BMI is not used to assess weight during pregnancy. Follow-up belongs to maternity care.

Very short or tall

The formula favours average heights: for very short people the result easily reads too low, and for very tall people too high.

Fluid retention and illness

Fluid build-up, for example in heart failure, raises weight without any change in body fat.

Where the fat sits

BMI does not show whether fat is around the abdomen or elsewhere. Waist circumference completes the picture.

Weight management

Discuss weight management with a doctor online

If your BMI is 25 or more — or your weight worries you for any other reason — a doctor reviews your health information with you, assesses your risk factors and explains which treatment options suit you.

  • The doctor assesses BMI, waist circumference and risk factors as a whole.
  • You go through your health status and possible medication together.
  • You get a personal assessment of your situation and an individual plan for effective, safe weight management.
Book a weight management consultation Open 365 days a year
Read more about weight management care
FAQ

Body mass index — frequently asked questions

For adults, the healthy target range is 18.5–25. For people over 65, a slightly higher BMI of around 23–29 is linked in studies with the best functional capacity and prognosis.

Read also