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Your BMI results:


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Classification Under weight
BMI

Your result:

BMI Classification Table
BMI Classification
Under 18.5 Underweight
18.5 - 24.9 Normal Weight
25-29.9 Overweight
30-34.9 Obesity Class I
35-39.9 Obesity Class II
Over 40 Obesity Class III

*This BMI calculator is not applicable if you are below 20 years old. BMI is interpreted differently for children and teens, even though it is calculated using the same formula as adult BMI. Please consult with your healthcare provider for BMI information for under 20s.

Your BMI calculator results: What does it mean?

Underweight BMI range

Being underweight could be a sign that you're not eating enough.

Recommendation

If you’re underweight, contact your doctor for further evaluation.

Frequently asked Questions

Why is BMI important to know?

BMI is a good way to check your risk of diseases related to body fat. Living with overweight or obesity is associated with an increased risk of mortality and other diseases or conditions. Generally, the higher your BMI, the greater the chance of developing other chronic obesity-related diseases, including:

  • Type II diabetes
  • Cardiovascular disease
  • Stroke
  • High blood pressure
  • Infertility
  • Depression and anxiety
  • Coronary heart disease
  • Dyslipidemia
  • Metabolic Dysfunction-Associated Steatohepatitis (MASH)
  • Gastroesophageal reflux disease (GERD)
  • Metabolic syndrome (MetS)
  • Urinary incontinence
  • Obstructive sleep apnea and breathing problems
  • Chronic kidney disease
  • Various types of cancer: including but not limited to - breast, colon, endometrial, oesophageal, kidney, ovarian, and pancreatic cancer
  • Knee osteoarthritis
  • Gallstone disease
  • Thrombosis
  • Gout
  • Increased risk of mortality compared to those with a healthy BMI

Ask your doctor for more information about any of these diseases and how they relate to your BMI. You can also learn more about the health benefits of losing weight here.

What are the limits of BMI?

BMI is a simple and objective measurement, but it can be misleading in certain cases and for some groups of people. Research has shown that BMI is less accurate in predicting the risk of disease in people who are older, athletes, those who are tall or short, and those with more muscular body types. For example, elite athletes or bodybuilders have more muscle and weigh more, which makes their BMI higher.

BMI also doesn't take into account:

  • Hereditary risk factors associated with obesity-related diseases, such as metabolic syndrome
  • Environmental and lifestyle factors other than obesity that can contribute to your risk of developing chronic disease
  • How body fat is distributed in individuals

It's important to remember that living with obesity doesn't necessarily mean you're unhealthy, just as being at a ‘normal’ weight doesn't mean you're healthy. Your BMI doesn't define you, but knowing and understanding your BMI can be a powerful tool for taking charge of your own health.

Regardless of your BMI, healthcare professionals recommend having a healthy diet and lifestyle. Talk to your doctor about your weight and health and evaluate what actions may be needed.

References
  1. Adult BMI categories (204) Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/bmi/adult-calculator/bmi-categories.html#:~:text=BMI%20is%20a%20calculated%20measure,BMI%20is%20a%20screening%20measure.
  2. Sharon, A. (2024) 11 signs that you’re not eating enough, Healthline. Available at: https://www.healthline.com/nutrition/signs-of-not-eating-enough#skin-problems
  3. Rueda-Clausen, C F et al, “Assessment of People Living with Obesity,” Can. Adult Obes. Clin. Pract. Guidel., pp. 1–17, 2020.Available: http://obesitycanada.ca/wp-content/uploads/2020/09/6-Obesity-Assessment-v5-with-links.pdf.
  4. Durrer Schutz, D. et al. (2019) ‘European practical and patient-centred guidelines for adult obesity management in Primary Care’, Obesity Facts, 12(1), pp. 40–66. doi:10.1159/000496183.
  5. Garvey, W T et al, “American Association of Clinical Endocrinologists and American College of Endocrinology comprehensive clinical practice guidelines for medical care of patients with obesity.” Endocrine Practice 2016;22:1–203. DOI: https://doi.org/10.4158/EP161365.GL
  6. Prevention -Coronary heart disease (2024) NHS choices. Available at: https://www.nhs.uk/conditions/coronary-heart-disease/prevention/
  7. Liu, Leiling et al. (2025) Safety and effects of anti-obesity medications on weight loss, cardiometabolic, and psychological outcomes in people living with overweight or obesity: a systematic review and meta-analysis. DOI: https://doi.org/10.1016/j.eclinm.2024.103020
  8. Health risks of Overweight & obesity (2023) National Institute of Diabetes and Digestive and Kidney Diseases. Available at: https://www.niddk.nih.gov/health-information/weight-management/adult-overweight-obesity/health-risks
  9. Kirk SFL, Ramos Salas X, Alberga AS, Russell-Mayhew S. Canadian Adult Obesity Clinical Practice Guidelines: Reducing Weight Bias in Obesity Management, Practice and Policy. Available from: https://obesitycanada.ca/guidelines/weightbias
  10. Factors affecting weight & health - NIDDK (2023) National Institute of Diabetes and Digestive and Kidney Diseases. Available at: https://www.niddk.nih.gov/health-information/weight-management/adult-overweight-obesity/factors-affecting-weight-health
  11. Estruch R & Ros E. The role of the Mediterranean diet on weight loss and obesity-related diseases. Reviews in Endocrine and Metabolic Disorders 2020; 21:315–327.
  12. Sanders LM et al. Effects of Whole Grain Intake, Compared with Refined Grain, on Appetite and Energy Intake: A Systematic Review and Meta-Analysis. Advances in Nutrition 2021; 30;12(4):1177-1195.
  13. Xu, Y. et al. (2024) ‘Relationship of vegetarianism with body weight loss and ASCVD’, Frontiers in Nutrition, 11. doi:10.3389/fnut.2024.1419743.
  14. Mayo Clinic. Weight loss: Gain control of emotional eating. Available at: https://www.mayoclinic.org/healthy-lifestyle/weight-loss/basics/weightloss-basics/hlv-20049483
  15. van der Valk ES, Savas M, van Rossum EFC. Stress and Obesity: Are There More Susceptible Individuals? Curr Obes Rep. 2018 Jun;7(2):193-203. doi: 10.1007/s13679-018-0306-y
  16. Calculating your calories burned (2024) Mayo Clinic. Available at: https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/exercise/art-20050999
  17. Ong J, Chirinos D & Yap B. Relationship Between Sleep Health and Your Weight: https://www.obesityaction.org/community/article-library/the-relationship-between-sleep-health-and-your-weight/
  18. NHS. How to get good sleep: Sleep and Tiredness: https://www.nhs.uk/live-well/sleep-and-tiredness/how-to-get-to-sleep/
  19. Powell-Wiley, T.M. et al. (2021) ‘Obesity and cardiovascular disease: A scientific statement from the American Heart Association’, Circulation, 143(21). doi:10.1161/cir.0000000000000973.
  20. van Walree, E.S. et al. (2022) ‘Disentangling genetic risks for metabolic syndrome’, Diabetes, 71(11), pp. 2447–2457. doi:10.2337/db22-0478.
  21. Canada, P.H.A. of (2024) Government of Canada, Canada.ca. Available at: https://www.canada.ca/en/public-health/services/chronic-diseases/chronic-disease-risk-factors.html (Accessed: 28 May 2025).
  22. Eating & physical activity to lose or maintain weight - NIDDK (2023) National Institute of Diabetes and Digestive and Kidney Diseases. Available at: https://www.niddk.nih.gov/health-information/weight-management/adult-overweight-obesity/eating-physical-activity.
  23. Ashwell, Margaret. (2011). Charts Based on Body Mass Index and Waist-to-Height Ratio to Assess the Health Risks of Obesity: A Review. The Open Obesity Journal. 311. 78-84. 10.2174/1876823701103010078.

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