BMI Result: 5ft 6in, 81 lbs (BMI 13.1) - Male
According to CDC and WHO standards, a BMI of 13.1 is classified as Underweight.
A male who is 5ft 6in tall and weighs 81lbs has a BMI of 13.1, 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 5ft 6in: 115 lbs – 154 lbs
Metric: 167.6 cm, 36.7 kg
📏 Healthy waist circumference for your height: 35" – 40" (below 40" for male)
So you're 5ft 6in and weigh 81lbs. Your BMI is 13.1, which falls into the Underweight category according to CDC and WHO standards. Let's break down what this means for your health.
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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 of average height, BMI is a reliable screening tool. The CDC recommends keeping waist circumference below 40 inches to minimize health risks.
Weight & Threshold
Gaining approximately 33.5 lbs would bring your BMI to 18.5, the start of the next category.
⬆️ Gaining approximately 33.5 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 35 years old, a man at 5ft 6in and 81lbs has a BMI of 13.1, 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 13.1 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.
Personalized Notes
Diet & Nutrition
At 5ft 6in and 81lbs, a BMI of 13.1 indicates underweight. For men of this height, the CDC recommends a healthy weight range of 114-154lbs. Focus on protein-rich foods and resistance training to build muscle mass.
Monitoring
At 5ft 6in, track your weight weekly. The healthy weight range for men at this height is 114-154lbs. Monitor waist circumference too—the CDC recommends below 40 inches.
Frequently Asked Questions
What health risks are associated with a BMI of 13.1 for a 5ft 6in man?
How do I calculate my BMI at 5ft 6in and 81lbs?
Am I at a healthy weight at 5ft 6in and 81lbs?
How common is a BMI of 13.1 for a 5ft 6in man?
Related Tools & Articles
💡 About this calculation: BMI = (81 × 703) ÷ (66 × 66) = 13.1 | Metric: 167.6 cm, 36.7 kg
📖 Recommended reading:
Editorial Review: This page was generated by the BMI Calculator Web Editorial Team and reviewed at template and content-pool level for accuracy and guideline alignment by Dr. Sarah K. Johnson, PhD, RD. All content is aligned with current WHO, CDC, and NIH guidelines.
Published: 2026-08-05