What is a healthy BMI?

According to the WHO, a healthy BMI for adults is between 18.5 and 24.9. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese. These thresholds apply to most adults but may not be suitable for athletes, the elderly, or certain ethnic groups.

How is BMI calculated?

BMI is calculated by dividing your weight in kilograms by the square of your height in metres: BMI = kg / m². In imperial units, use: BMI = (lbs / in²) × 703. For example, a person weighing 70kg at 1.75m has a BMI of 70 ÷ (1.75 × 1.75) = 22.9.

What are the WHO BMI categories?

The WHO classifies BMI as follows: Under 18.5 = Underweight; 18.5–24.9 = Normal weight; 25.0–29.9 = Overweight; 30.0–34.9 = Obese Class I; 35.0–39.9 = Obese Class II; 40 or above = Obese Class III (severely obese). Our BMI calculator shows which category you fall into instantly.

Is BMI accurate for everyone?

BMI has limitations. It does not distinguish between muscle and fat, so athletes may be classified as overweight despite being healthy. It can also underestimate health risk in some ethnic groups and is less reliable for the elderly. For a fuller picture, consider waist circumference and body fat percentage alongside BMI.

BMI Prime is your BMI divided by 25 (the upper limit of the healthy range). A BMI Prime of 1.0 means you are exactly at the upper boundary of a healthy weight. Below 0.74 is underweight; 0.74–1.0 is normal; above 1.0 is overweight or obese. It makes it easy to see how close you are to the healthy range.

⚕️ BMI-lommeregner

Gratis, accurate, GDPR compliant. All calculations run in your browser — no data is ever stored or shared.

Unit System

Vægt (kg)

Højde (cm)

⚠️ Not medical advice. BMI is a screening tool only and does not diagnose health conditions. Consult a qualified healthcare professional for personal health guidance. WHO classification used.

About the BMI Lommeregner

BMI Calculator er gratis at bruge og alle beregninger kører udelukkende i din browser. Body Mass Index (BMI) er et bredt brugt screeningsværktøj, der estimerer, om en person har en sund kropsvægt i forhold til sin højde. Det beregnes ved at dividere kropsvægt i kilogram med kvadratet på højden i meter (kg/m²). Vores lommeregner understøtter både metriske (kg/cm) og imperiale (lbs/fod/tommer) input.

BMI Categories (WHO Classification)

Below 18.5 — Underweight
18.5 – 24.9 — Normalvægt
25.0 – 29.9 — Overvægtig
30.0 – 34.9 — Fedme (klasse I)
35.0 and above — Fedme (klasse II/III)

What Is BMI Prime?

BMI Prime is a dimensionless number that represents the ratio of your actual BMI to the upper boundary of the healthy weight range (25). A BMI Prime of 1.0 means you are exactly at the top of the healthy range. Values below 1.0 indicate underweight or healthy weight, while values above 1.0 indicate overweight or obesity.

Limitations of BMI

While BMI is a useful population-level screening tool, it does not directly measure body fat and does not account for age, sex, ethnicity, or muscle mass. A person with high muscle mass may have a high BMI without excess body fat, while an older person may have a normal BMI but carry an unhealthy proportion of body fat. Always consider BMI alongside other health indicators.

Sundt vægter interval

Efter beregning af dit BMI viser dette værktøj også det vægtsinterval, der svarer til et sundt BMI (18,5–24,9) ved din specifikke højde. Dette giver dig et praktisk målinterval frem for et enkelt tal, hvilket er mere nyttigt til at sætte realistiske sundhedsmål i samråd med din sundhedsudbyder.

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Vigtig bemærkning: Dette værktøj er beregnet til at give estimater og bør ikke bruges som erstatning for professionel rådgivning. Oplysninger genereret af disse lommeregnere kan være ufuldstændige og tager ikke højde for alle individuelle omstændigheder. Søg altid rådgivning fra en certificeret ekspert (som en finansiel rådgiver, sundhedsperson eller licenseret ingeniør), inden du handler baseret på disse resultater.

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