What is BMI? 

BMI, or Body Mass Index, is a number calculated from a person’s height and weight. It’s a useful screening tool to identify if a person has a healthy body weight for their height. While BMI doesn’t directly measure body fat, it offers an indication of whether you are underweight, at a healthy weight, overweight, or obese (World Health Organisation, 2020). 

Why is BMI important? 

BMI is a great tool for: 

• Assessing health risks: High or low BMI can indicate increased risk for conditions like heart disease, diabetes, or high blood pressure (American Heart Association, 2022). 

• Tracking for weight management: Knowing your BMI can help you keep track of whether you need to lose weight, maintain your current weight, or gain weight in a healthy way (National Heart, Lung, and Blood Institute, 2021). 

• Starting healthy habits: Your BMI can give you the motivation to adopt a balanced diet and exercise regularly (Harvard T.H. Chan School of Public Health, 2020).

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How to calculate your BMI

The BMI formula is simple: 

BMI = (Weight in kilograms) / (Height in metres)² 

If you prefer a quick, easy, and accurate calculation, you can simply use our online BMI calculator! By entering your weight and height, our tool will instantly provide you with your BMI number and its corresponding category (Centres for Disease Control and Prevention, 2021). 

BMI categories

Once you have your BMI number, it’s important to know what it means. According to the World Health Organisation (WHO, 2020), the BMI categories are as follows: 

• Underweight: BMI less than 18.5 

• Normal weight: BMI 18.5 – 24.9 

• Overweight: BMI 25 – 29.9 

• Obese: BMI 30 or greater

Important Note: While BMI is a useful tool for most people, it doesn’t account for factors like muscle mass, bone density, or age, so it’s always good to consult with a healthcare provider for a more comprehensive evaluation (Mayo Clinic, 2022). 

Benefits of using a BMI calculator 

• Quick and easy: It takes just seconds to calculate your BMI. No need for complicated measurements or lab tests.  

• Accessible to everyone: Whether you’re at home, in the office, or on the go, you can access a BMI calculator from your computer or smartphone. 

• Track your progress: By regularly calculating your BMI, you can track your weight loss or weight gain progress and make adjustments as needed. 

• Motivate healthy changes: Seeing where you stand with your BMI can help motivate you to adopt healthier habits like exercising regularly or making better food choices (NIH, 2020). 

How to improve your BMI

If your BMI falls outside the healthy range, there are steps you can take to improve it. It’s important that you talk to your healthcare practitioner for advice, but here are some general tips:

Adopt a balanced diet

Eating a nutritious and well-rounded diet that includes plenty of fruits, vegetables, lean proteins, and whole grains can help you manage your weight (Harvard T.H. Chan School of Public Health, 2020).

Exercise regularly

Engage in both cardio and strength-training exercises to help burn calories and build muscle mass, which can improve your BMI.

Stay hydrated

Drinking enough water can boost your metabolism and help with weight management.

Get enough sleep

Quality sleep is vital for maintaining a healthy weight. Aim for 7-9 hours of sleep per night.

Consult a professional

If you’re unsure about your BMI or how to improve it, speaking with a healthcare provider or nutritionist can help you create a personalised plan. 

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FAQs about BMI

Is BMI a perfect measure of health?  

No, BMI is a useful screening tool but does not take into account muscle mass, bone density, or other individual health factors. It’s best to use it as one part of your health assessment (Mayo Clinic, 2022). 

Can BMI help me lose weight?  

While BMI can help assess whether you need to lose weight, the best approach to weight loss is a combination of a balanced diet and regular exercise, tailored to your individual needs (NHLBI, 2021).  

Can my BMI change as I get older?  

Yes, your BMI can change with age as muscle mass decreases and body fat percentage increases. It’s important to adjust your health goals as your body changes. 

Is BMI different for children?  

Yes, BMI for children is assessed differently, considering their age and gender. Children’s BMI is plotted on a growth chart to assess their weight status (American Academy of Pediatrics, 2019). 

Conclusion

A BMI calculator is a simple yet powerful tool that helps you assess your weight in relation to your height and provides a snapshot of your overall health. Whether you’re working toward a healthier lifestyle or simply keeping track of your health, understanding your BMI is a great place to start. 

Remember, BMI is just one piece of the puzzle, and maintaining a healthy weight involves more than just numbers. It’s about making consistent, healthy choices that improve your well-being in the long run. 

References

1. World Health Organization (WHO). (2020). Body Mass Index – BMI. Retrieved from https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight 

2. National Heart, Lung, and Blood Institute (NHLBI). (2021). Assessing Your Weight and Health Risk. Retrieved from https://www.nhlbi.nih.gov/health/educational/lose_wt/risk.htm 

3. Centers for Disease Control and Prevention (CDC). (2021). BMI Calculators. Retrieved from https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html 

4. Mayo Clinic. (2022). Body Mass Index (BMI). Retrieved from https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/bmi/faq-20058397 

5. Harvard T.H. Chan School of Public Health. (2020). The Nutrition Source – Obesity Prevention. Retrieved from https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/obesity-prevention/ 

6. American Heart Association (AHA). (2022). BMI and Heart Disease. Retrieved from https://www.heart.org/en/healthy-living/healthy-eating/losing-weight/bmi-and-heart-disease 

7. National Institutes of Health (NIH). (2020). Body Mass Index and Healthy Weight. Retrieved from https://www.niddk.nih.gov/health-information/weight-management/adult-overweight-obesity/bmi 

8. American Academy of Pediatrics. (2019). BMI for Children and Teens. Retrieved from https://pediatrics.aappublications.org/content/early/2019/09/16/peds.2019-2120