Bone Age Estimation Calculator
Estimate bone age for children based on chronological age, height, and gender.
Understand skeletal maturity and growth potential.
Bone age (skeletal age) is a measure of how mature a child’s bones are compared to their chronological age. It helps pediatricians assess growth potential and predict adult height.
How bone age works: Bone age is typically determined by X-ray of the left hand and wrist, compared to a standard atlas (Greulich-Pyle method). This calculator provides a simplified estimation based on height percentile.
Height-for-age percentile concept:
- If a child is taller than average for their age, their bone age may be advanced (bones maturing faster).
- If a child is shorter than average, their bone age may be delayed (more growth potential remaining).
Average heights by age (approximate midpoints):
| Age | Boys (cm) | Boys (in) | Girls (cm) | Girls (in) |
|---|---|---|---|---|
| 2 | 87 | 34.3 | 86 | 33.9 |
| 5 | 110 | 43.3 | 109 | 42.9 |
| 8 | 128 | 50.4 | 127 | 50.0 |
| 10 | 138 | 54.3 | 138 | 54.3 |
| 12 | 149 | 58.7 | 152 | 59.8 |
| 14 | 164 | 64.6 | 160 | 63.0 |
| 16 | 174 | 68.5 | 163 | 64.2 |
Key concepts:
- Advanced bone age: Bones are maturing faster than normal. The child may stop growing earlier.
- Delayed bone age: Bones are maturing slower. The child may have more time to grow.
- A difference of up to 1 year between bone age and chronological age is generally considered normal.
Predicted adult height uses the Bayley-Pinneau method concept: current height divided by the percentage of adult height typically achieved at the child’s bone age.
Important: This is a simplified estimation tool. Actual bone age requires an X-ray evaluated by a trained physician. Always consult a pediatrician for growth concerns.