Calculator Inputs
Example Data Table
| Profile | Sex | Height (cm) | ASM (kg) | Weight (kg) | SMI (kg/m²) | General View |
|---|---|---|---|---|---|---|
| Case A | Male | 175 | 24.0 | 72.0 | 7.84 | Good range |
| Case B | Male | 180 | 21.5 | 78.0 | 6.64 | Below reference |
| Case C | Female | 165 | 18.0 | 58.0 | 6.61 | Good range |
| Case D | Female | 160 | 14.0 | 55.0 | 5.47 | Borderline good |
| Case E | Male | 170 | 26.0 | 76.0 | 9.00 | Strong range |
Formula Used
This calculator uses appendicular skeletal muscle mass and height to estimate skeletal muscle index.
SMI = ASM ÷ (Height in meters)²
ASM to Weight % = (ASM ÷ Body Weight) × 100
Good ASM Target = Good SMI Threshold × (Height in meters)²
Strong ASM Target = High SMI Threshold × (Height in meters)²
ASM means appendicular skeletal muscle mass. That usually covers lean muscle in the arms and legs.
How to Use This Calculator
- Select sex and your preferred reference method.
- Enter age, height, body weight, and appendicular muscle mass.
- Choose activity level and your current goal focus.
- Press Calculate Index to show results above the form.
- Review SMI, category, target ASM, and gap analysis.
- Use CSV or PDF export buttons to save your result.
Frequently Asked Questions
1. What is skeletal muscle index?
Skeletal muscle index estimates muscle relative to height. It helps compare muscle status across people with different body sizes.
2. What does ASM mean here?
ASM means appendicular skeletal muscle mass. It usually refers to muscle in the arms and legs measured by body composition tools.
3. Why does the calculator ask for height?
Height is part of the core formula. Dividing muscle mass by height squared creates a more comparable index.
4. Is a higher number always better?
Not always. A higher index often suggests more muscle, but context matters. Training level, health status, and measurement method still matter.
5. Why are there DXA, BIA, and generic options?
Different tools use different reference patterns. These options help you compare your result with a method closer to your measurement source.
6. Can this replace a medical assessment?
No. This is a fitness planning tool. Clinical evaluation should come from a qualified professional who can review full health context.
7. What is the planning target section?
It gives a practical target based on your activity and goal. It is a planning aid, not a diagnosis.
8. How often should I track skeletal muscle index?
Monthly or every few weeks works well for most people. Daily changes are usually too small to interpret well.