BMI Result: 6ft 9in, 143 lbs (BMI 15.3) - Male
According to CDC and WHO standards, a BMI of 15.3 is classified as Underweight.
A male who is 6ft 9in tall and weighs 143lbs has a BMI of 15.3, which falls into the Underweight category used by the CDC and WHO for adults.
| Category | BMI Range |
|---|---|
| Underweight | < 18.5 |
| Underweight | < 18.5 |
| Obese | ≥ 30 |
Healthy weight range for 6ft 9in: 173 lbs – 232 lbs
Metric: 205.7 cm, 64.9 kg
📏 Healthy waist circumference for your height: 35" – 40" (below 40" for male)
So you're 6ft 9in and weigh 143lbs. Your BMI is 15.3, which falls into the Underweight category according to CDC and WHO standards. Let's break down what this means for your health.
Adjust Your Numbers
Change your height or weight to see how your BMI changes.
Understanding Your BMI
A BMI below 18.5 may indicate nutritional insufficiency. According to the CDC, this range is associated with increased risk of bone density loss and immune function decline. Consulting a healthcare provider is recommended for a thorough nutritional assessment.
What This Means for Your Height
For men over 6ft, BMI may overestimate body fat due to higher muscle mass. Consider waist circumference and body fat percentage for a more accurate assessment.
Weight & Threshold
Gaining approximately 29.9 lbs would bring your BMI to 18.5, the start of the next category.
⬆️ Gaining approximately 29.9 lbs would put you in the Normal BMI range.
Waist & Health
The CDC recommends that men keep waist circumference below 40 inches. A waist-to-height ratio below 0.5 is also associated with lower health risks.
Age Context
For adults in early to middle adulthood (20-44), BMI is a reliable screening tool. At 21 years old, a man at 6ft 9in and 143lbs has a BMI of 15.3, which falls into the Underweight category according to CDC and WHO standards.
Your BMI is below the healthy range. Consider consulting a healthcare provider for a nutritional assessment.
👉 Check your Healthy Weight Range for more context.
👉 Measure your Body Fat Percentage for a more complete picture.
Health Analysis
Recommendations
General Health
A BMI of 15.3 is below the CDC and WHO healthy range of 18.5-24.9. This may indicate nutritional insufficiency. Consulting a healthcare provider is recommended for a thorough nutritional assessment.
Monitoring
In addition to BMI, pay attention to waist circumference. The CDC recommends males stay under 40 inches. Regular tracking of your measurements over time provides the most useful insight into your health trends.
Next Steps
If you're concerned about your weight or body composition, a healthcare provider can offer personalized guidance based on your full health profile.
Frequently Asked Questions
How does a BMI of 15.3 affect health for a 6ft 9in man?
Is 143lbs overweight for a 6ft 9in man?
How do I calculate my BMI at 6ft 9in and 143lbs?
What percentage of men have a BMI of 15.3 at 6ft 9in?
Related Tools & Articles
💡 About this calculation: BMI = (143 × 703) ÷ (81 × 81) = 15.3 | Metric: 205.7 cm, 64.9 kg
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Published: 2026-08-29