- Formula: weight (kg) divided by height (m) times height (m).
- Overweight: BMI 25-30. Obesity: 30 or higher.
- Surgery: BMI 40, or 35 with a related condition.
- Gastric balloon: from about BMI 27-30, per clinic.
- BMI is a starting point; health counts too.
How do you calculate your BMI?
Divide your weight in kilograms by your height in metres squared. Example: someone who is 1.70 metres tall and weighs 116 kilograms calculates 116 divided by 1.70 times 1.70, which is 2.89. The result is a BMI of about 40. At the same height, BMI 35 lies around 101 kilograms.
According to the Dutch Health Monitor 2024, half of Dutch adults are overweight and 15.6 percent have obesity. Only a small part of that group qualifies for surgery, because the thresholds are deliberately higher than the definition of obesity.
Why BMI does not tell the whole story
BMI does not account for muscle mass or fat distribution. Especially fat in and around the abdomen increases the risk of diseases such as cardiovascular disease, diabetes, gallstones, several types of cancer, high blood pressure and sleep apnoea, according to Vitalys. That is why, with a BMI between 35 and 40, it matters whether you have weight-related conditions.
What should you do with your result?
With a BMI of 40 or higher, or 35 or higher with conditions such as type 2 diabetes, sleep apnoea or high blood pressure, discuss a referral to a bariatric centre with your GP. With a BMI between 30 and 35, a lifestyle programme, medication or a gastric balloon are more likely next steps, except with poorly controlled type 2 diabetes.
With a BMI between 25 and 30, a healthy lifestyle is the basis. A BMI below 18.5 counts as underweight; after surgery that is rare, but the team does watch for it.
BMI classes and what belongs to them
Advantages
| Advantage | Explanation |
|---|---|
| BMI 25-30 | overweight: lifestyle as the basis |
| BMI 30-35 | obesity: lifestyle, medication, possibly a balloon |
| BMI 35-40 | surgery with a related condition |
| BMI 40 or higher | surgery, even without a condition |
Points of attention
| Point of attention | Explanation |
|---|---|
| Muscle mass | can make BMI look too high |
| Abdominal fat | more risk than BMI shows |
| Age | thresholds apply from 18 |
| Snapshot | your weight history counts too |
Cost and insurance (2026)
Your BMI partly decides whether a treatment is covered.
| Item | Amount or arrangement |
|---|---|
| Surgery with indication | €385 deductible 2026 |
| Lifestyle programme (GLI) | covered by the basic package |
| Gastric balloon | about €3,000-€5,000, not covered |
BMI and weight loss surgery: key figures
| Feature | Value |
|---|---|
| Adults with obesity in NL (2024) | 15.6% |
| Adults overweight in NL | 50.0% |
| Obesity from BMI | 30 |
| Surgery from BMI | 35 with a condition, or 40 |
| Range per GGD region | 11.6% to 19.2% |
BMI 30, 35 and 40 by height
| Height | BMI 30 / 35 | BMI 40 |
|---|---|---|
| 1.55 m | 72 / 84 kg | 96 kg |
| 1.65 m | 82 / 95 kg | 109 kg |
| 1.75 m | 92 / 107 kg | 123 kg |
| 1.85 m | 103 / 120 kg | 137 kg |
| 1.95 m | 114 / 133 kg | 152 kg |
Step by step
- Measure. Weigh yourself and measure your height without shoes.
- Calculate. Weight divided by height squared.
- Conditions. Note weight-related conditions.
- GP. Discuss the result and the next step.
- Referral. With an indication, to a bariatric centre.
Read next
- Eligibility criteria — all criteria
- Gastric balloon from BMI 27-30 — non-surgical
- Types of weight loss surgery — which operation
- Cost and insurance — coverage
BMI after surgery
After weight loss surgery your BMI is also a way to follow your progress, but look beyond the number: how you feel, whether conditions improve and whether your blood values stay good.
Use the BMI check on the English home page for a first indication, and always discuss the result with your GP, who knows your medical history and which next step makes sense for you.
BMI and waist circumference
For some treatments, such as the gastric balloon at Vitalys, waist circumference is also measured. It shows how much fat sits around the abdomen, which carries more health risk than BMI alone reveals.
Discuss both numbers with your GP.
Frequently asked questions about BMI and weight loss surgery
Divide your weight in kilograms by your height in metres squared. At 116 kilograms and 1.70 metres that is 116 divided by 2.89, a BMI of about 40.
A BMI of 40 or higher, or 35 or higher with a weight-related condition. With poorly controlled type 2 diabetes, Vitalys already considers a BMI of 30 to 35.
From a BMI of 30. Between 25 and 30 is called overweight.
The team looks at your current BMI and your weight history. After the information session, centres ask you not to gain weight before surgery.
Less so. Muscle is heavy, so BMI can be high without much fat. That is why the team looks beyond BMI at your health and conditions.
Vitalys mentions, among others, high blood pressure, joint problems, high cholesterol, sleep apnoea, diabetes, asthma, COPD, incontinence, fatty liver and a wish to become pregnant.
Then a lifestyle programme, medication or a gastric balloon are more likely options. Surgery only with poorly controlled type 2 diabetes.
Yes, with the BMI check on the English home page of this website. Enter your height, weight and any conditions for a first indication.
For weight loss surgery, 18 is the minimum age. For young people doctors use adjusted growth charts and a separate guideline.
That depends on your starting weight and the procedure. On average you lose about 20 to 40 percent of your total body weight, and your BMI drops in the same proportion.
Call +31 6 38048347 (Mon–Fri 09:00–17:00) or email info@maagverkleining-info.nl. This page is also available in Dutch.
Sources
- Vitalys (Rijnstate): criteria and FAQ
- Gezondheidsmonitor Volwassenen en Ouderen 2024, RIVM, CBS and GGD
- Richtlijn Chirurgische behandeling van obesitas, NVvH
- YourWeightcare: balloon criteria
Search terms leading here: BMI for weight loss surgery, BMI calculator bariatric surgery Netherlands, BMI 35 weight loss surgery, BMI 40 gastric bypass.
Author: Gijs Bodenstaff. Last reviewed: September 2026.