# Osteoporosis Risk Calculator (ORAI and OST)

URL: https://speedycalculator.com/calculators/health/osteoporosis-risk-score/
Last updated: 2026-10-30

> The osteoporosis risk calculator uses the Osteoporosis Risk Assessment Instrument (ORAI) and the Osteoporosis Self-assessment Tool (OST) – based on age, weight and oestrogen use – to decide who should have a bone density (DXA) scan.

## Inputs

- Age (years)
- Weight (kg, lb, st, g)
- Currently taking oestrogen (HRT)

## Results

- ORAI score
- ORAI recommendation
- OST score
- OST risk

## Formula

```
ORAI: age ≥ 75 15, 65–74 9, 55–64 5; weight < 60 kg 9, 60–69 kg 3; not taking oestrogen 2 → score ≥ 9: DXA recommended
OST = 0.2 × (weight kg − age); < −4 high, −4 to −1 moderate, > −1 low risk
```

## Explanation

Osteoporosis has no symptoms until a bone breaks. Simple tools using age and weight identify most women with low bone density and help target DXA scans. Men can use the OST too.

### How to use the Osteoporosis Risk Calculator

- **Age**
- **Weight**
- **Currently taking oestrogen (HRT)**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter age, weight and oestrogen use.

### Tips

- Assess on a typical day, not during an acute illness, unless the tool asks otherwise.
- Involve family or carers who know the person's usual abilities.
- Repeat assessments regularly to track change.
- Use results to plan support, not to label people.

### Common mistakes to avoid

- Scoring what the person could do rather than what they actually do.
- Ignoring hearing or vision problems during cognitive tests.
- Using a single score to decide care without a full assessment.

### Inputs explained

FieldWhat to enterAgeIn yearsWeightUnits: kg, lb, st, gCurrently taking oestrogen (HRT)Choose one: No, Yes

### Example values

How the main result changes when **Age** changes and everything else stays at the example values above:

Age (years)ORAI score (points)51116820852610226
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Age: 68 years; Weight: 58 kg; Currently taking oestrogen (HRT): No.

Results — **ORAI score = 20 points**; ORAI recommendation = Bone density (DXA) test recommended; OST score = -2; OST risk = Moderate risk.

## Key terms

- **DXA**: Dual-energy X-ray absorptiometry.

## FAQ

**Who should have a bone density scan?**
All women 65 and over, and younger women and men with risk factors.

**What else raises osteoporosis risk?**
Previous fracture, steroids, smoking, alcohol, rheumatoid arthritis and family history.

**What is FRAX?**
A tool estimating 10-year fracture risk, often used after DXA.


## Sources

- [Cadarette SM et al. Development and validation of the ORAI to facilitate selection of women for bone densitometry. CMAJ, 2000](https://pubmed.ncbi.nlm.nih.gov/10822107/)