Bone Density Score Calculator

T-score and Z-score interpretation from DEXA scan.

T-score

Z-score

Patient age (years)

Sex

Prior fragility fracture?

Parent hip fracture?

BMI (kg/m²)

Tab to move between fields

WHO classification (0-3)

BMD % of young-adult peak89

10-yr major fracture risk (%)11.7

10-yr hip fracture risk (%)3.5

Treatment threshold met? (0/1)1

Z-score flag (0/1)0

ClassificationNormal bone density

How to Use This Calculator

Enter the T-score from your DEXA scan report — this compares your bone mineral density to a young-adult reference (normal ≥ −1.0).
Enter the Z-score from the DEXA report — this compares your BMD to age-matched peers (≤ −2.0 warrants secondary cause evaluation).
Enter the patient's Age in years, Sex (0 = Male, 1 = Female), and BMI in kg/m².
Indicate Prior fragility fracture (0/1) and Parent hip fracture history (0/1) — both significantly raise fracture risk.
Review the WHO classification (Normal / Osteopenia / Osteoporosis), 10-year major fracture risk (%), 10-year hip fracture risk (%), and whether the treatment threshold is met.

How the result changes with T-score

T-score: DEXA T-score comparing BMD to young-adult reference. Normal ≥ -1.0.
Z-score: DEXA Z-score comparing BMD to age-matched reference. ≤ -2.0 is below expected.
Patient age (years): Age in years. Fracture risk increases with age.
Sex: 0 = Male, 1 = Female. Women have higher fracture risk.
Prior fragility fracture?: 0 = No, 1 = Yes. Prior fracture roughly doubles future fracture risk.
Parent hip fracture?: 0 = No, 1 = Yes. Family history increases risk by ~40%.
BMI (kg/m²): Body mass index. Low BMI (<20) increases fracture risk.

WHO classification (0-3): 0=Normal, 1=Osteopenia, 2=Osteoporosis, 3=Severe osteoporosis
BMD % of young-adult peak: Estimated bone mineral density as percentage of peak young-adult value.
10-yr major fracture risk (%): Estimated 10-year probability of a major osteoporotic fracture (hip, spine, wrist, humerus).
10-yr hip fracture risk (%): Estimated 10-year probability of hip fracture.
Treatment threshold met? (0/1): 1 if pharmacologic treatment is recommended per NOF/NOGG guidelines.
Z-score flag (0/1): 1 if Z-score ≤ -2.0, suggesting evaluation for secondary causes.

Identify Input Parameters
4 parameters
T-score = -1, Z-score = 0, Patient age (years) = 65, Sex = 1 = 7 input(s) provided
Calculate WHO classification
0 = 0
Calculate BMD % of young-adult peak
BMD % of young-adult peak
89 = 89
Calculate 10-yr major fracture risk
10-yr major fracture risk
11.7 = 11.7