€45Weight Management
Talk any result through with a registered doctor by video, and get the checks that BMI cannot give you.
15 min
Free health tool
BMI calculator Spain
Enter your height and weight to see your body mass index and where it sits on the World Health Organization adult scale.
- Metric and imperial (kg, stone, pounds)
- WHO adult weight categories
- Runs in your browser — nothing is sent or stored
Your BMI
cm
kg
24,2
Healthy weight
Within the range the WHO classes as healthy for adults.
Where your BMI sits on the WHO scale
1518.525303540
- Healthy weight for your height
- 54 – 72 kg
- Distance to the healthy range
- Inside the healthy range
Want to keep it there? Our clinicians can help you build habits that hold.
Online GP consultationBMI is a screening measure, not a diagnosis. It cannot tell muscle from fat and is not valid during pregnancy or for under-18s.
01
What your BMI result means
The World Health Organization groups adult BMI into the bands below. They describe a population, not a person: two people with the same BMI can be in very different health.
Under 18.5
- Category
- Underweight
- What it usually prompts
- Worth a doctor's conversation, especially if unintentional
18.5 – 24.9
- Category
- Healthy weight
- What it usually prompts
- No action needed on BMI grounds alone
25.0 – 29.9
- Category
- Overweight
- What it usually prompts
- Lifestyle review; check blood pressure and cholesterol
30.0 – 34.9
- Category
- Obesity class I
- What it usually prompts
- Structured weight management is usually offered
35.0 – 39.9
- Category
- Obesity class II
- What it usually prompts
- Medical review; screening for related conditions
40.0 and over
- Category
- Obesity class III
- What it usually prompts
- Specialist weight management referral
02
How BMI is calculated
BMI is your weight in kilograms divided by the square of your height in metres. That is the whole formula — there is no age, sex or body-composition term in it.
Worked example: someone 1.75 m tall weighing 78 kg has a BMI of 78 ÷ (1.75 × 1.75) = 25.5, which falls in the overweight band.
Imperial entries are converted first (1 stone = 6.35 kg, 1 inch = 2.54 cm), so the result is identical either way.
03
What BMI does not tell you
BMI is a screening number, not a diagnosis. It is useful precisely because it is crude — it needs only a tape measure and a scales — but that is also its limit.
- It cannot separate muscle from fat. Well-muscled people are routinely classed as overweight.
- It ignores where fat sits. Waist circumference predicts cardiometabolic risk better than BMI does.
- It is not validated for pregnancy — use your pre-pregnancy BMI for maternity care planning.
- Children and teenagers need age-and-sex centile charts, not the adult bands above.
- In adults over 65 a BMI slightly above 25 is not consistently linked to worse outcomes.
04
When to talk to a doctor about your weight
- You have lost or gained weight without trying to.
- Your BMI is 30 or above, or 25 and above alongside high blood pressure, high cholesterol or raised blood sugar.
- You are being investigated for, or already treated for, type 2 diabetes, sleep apnoea, PCOS or fatty liver disease.
- You want to discuss medically supervised weight management rather than another diet.
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BMI calculator — FAQs
What is a healthy BMI for an adult?
For most adults aged 18 to 65, the World Health Organization considers a BMI between 18.5 and 24.9 to be the healthy range. Above 25 is classed as overweight and 30 or above as obesity. These are population thresholds, so a single reading is a prompt to look further, not a verdict.
Is BMI calculated differently for men and women?
No. The formula and the adult categories are identical. Women generally carry a higher proportion of body fat than men at the same BMI, which is one of the reasons the number is only a starting point.
How accurate is a BMI calculator?
The arithmetic is exact — the uncertainty is in what BMI measures. It correlates reasonably well with body fat across a population but can misclassify individuals, particularly athletes, older adults and people with a lot of muscle.
What should I do if my BMI is in the obese range?
Have your blood pressure, cholesterol and blood glucose checked, and talk to a doctor about a plan you can actually sustain. Weight management that includes medical review works considerably better than dieting alone.
Does this BMI calculator store my details?
No. The calculation runs entirely in your browser. Nothing you type is sent to our servers or saved.
Do I need a BMI to get weight-loss treatment?
Clinicians normally use BMI as one of the entry criteria for weight management programmes, usually alongside your medical history and any weight-related conditions. Your doctor will confirm what applies to you.
Does the Spanish health system use BMI?
Yes. BMI is the first-line screening measure in Spanish practice, as it is internationally — read alongside waist circumference, blood pressure and blood tests rather than on its own. A raised BMI prompts further assessment; it is not a diagnosis by itself.
Where can I get my BMI checked in Spain?
Any medical appointment includes height and weight, and most pharmacies will measure them too. You can also work it out here and bring the number to a consultation — our registered doctors can review it alongside your blood pressure, cholesterol and blood glucose.
Want to talk your result through?
Book a video consultation with a registered doctor and get a plan built around your history, not a number.