Health calculators

Frax Calculator

Updated Jul 13, 2026 By Jehan Wadia
Rate Formulas Medical disclaimer
0
fracture risk assessments completed since June 1, 2011

Step 1: Region

Step 2: Demographics

Unit system
Age entry mode
Sex
Typical clinical range: 35–200 kg.
Calculated BMI: 23.9 kg/m²

Step 3: Clinical Risk Factors

Step 4: Bone Density (Optional)

Bone Mineral Density (BMD) — Optional. Adding BMD improves calculation accuracy. Leave blank to use clinical risk factors only. Anatomical site: Femoral Neck

BMD input mode
T-scores usually fall between −5.0 and +3.0.

Your 10-Year Fracture Risk

10-Year Probability of Hip Fracture
6.2%
High Risk
0%▏ 3% treatment threshold30%
10-Year Probability of Major Osteoporotic Fracture
16.9%
(Clinical spine, forearm, hip, or shoulder fracture)
Moderate Risk
0%▏ 20% treatment threshold40%

Population Comparison

Major Fracture — Site Breakdown
Your Risk vs. Intervention Threshold
Your Inputs (click to expand)
Step-by-Step Solution

Introduction

The FRAX Calculator estimates your chance of breaking a bone in the next 10 years. It was created by the World Health Organization to help doctors decide who needs treatment for weak bones, also known as osteoporosis. This tool looks at your age, sex, weight, height, and seven key risk factors — like past fractures, smoking, and steroid use — to give you two scores: your 10-year risk of a hip fracture and your 10-year risk of a major osteoporotic fracture (hip, spine, forearm, or shoulder).

You can also add a bone density measurement from a DXA scan if you have one. This makes the results more accurate, but it is not required. The calculator works without it by using your body mass index (BMI) instead. If you need to check your BMI first, you can use our BMI Calculator.

Your results include a risk level — low, moderate, or high — based on widely used treatment thresholds. A hip fracture risk of 3% or higher or a major fracture risk of 20% or higher generally means treatment should be considered. Use these results to start a conversation with your doctor about bone health and next steps.

How to Use Our FRAX Fracture Risk Calculator

Enter your basic health details and risk factors below. The calculator will give you your 10-year chance of a hip fracture and a major osteoporotic fracture.

Country: Pick the country where you live. This sets the fracture risk model for your region.

Unit System: Choose metric (kg and cm) or imperial (lbs and ft-in) for your weight and height.

Age: Enter your age in years or switch to date of birth mode and type in your birthday. The tool works for ages 40 to 90. If you are unsure of your exact age from a date of birth, our Age Calculator can help.

Sex: Select female or male. This refers to your biological sex at birth.

Weight: Enter your body weight. The tool uses this to calculate your BMI. If you want to know where your weight falls relative to clinical benchmarks, try our Ideal Body Weight Calculator.

Height: Enter your height. If you chose imperial, fill in both the feet and inches fields. You can also use our Height Calculator if you need to estimate or convert your height.

Previous Fracture: Select "Yes" if you have ever broken a bone as an adult from a minor fall or less.

Parent Hip Fracture: Select "Yes" if either of your biological parents broke a hip.

Current Smoking: Select "Yes" if you smoke tobacco right now in any form.

Glucocorticoid Use: Select "Yes" if you take oral steroids such as prednisolone at 5 mg or more per day for 3 months or longer.

Rheumatoid Arthritis: Select "Yes" if a doctor has confirmed you have rheumatoid arthritis. If you have an inflammatory spinal condition and want to track disease activity, our BASDAI Calculator may also be useful.

Secondary Osteoporosis: Select "Yes" if you have a condition strongly tied to bone loss, such as type 1 diabetes, untreated hyperthyroidism, or early menopause. If you manage diabetes and want to monitor blood sugar trends, our A1C Calculator can help.

Alcohol (3+ Units/Day): Select "Yes" if you drink 3 or more units of alcohol each day. One unit is about one beer, one small glass of wine, or one shot of spirits. Not sure how many units you consume? Our Alcohol Unit Calculator can help you figure that out.

Bone Density (Optional): If you have had a DXA scan, choose T-score or BMD (g/cm²) mode and enter your femoral neck value. Leave this blank if you have not had a scan. Adding bone density makes the result more accurate. A T-score is a type of standard deviation measure — if you want to understand how standard scores work more broadly, you can explore our Z Score Calculator.

Press Calculate Risk to see your results. You will get your 10-year hip fracture risk, your 10-year major osteoporotic fracture risk, a risk band (low, moderate, or high), a comparison to population averages, and a step-by-step breakdown of the math.

What Is the FRAX Fracture Risk Calculator?

FRAX stands for Fracture Risk Assessment Tool. It was created by the World Health Organization (WHO) to help doctors figure out how likely a person is to break a bone in the next 10 years. It focuses on two types of fractures: hip fractures and major osteoporotic fractures (breaks at the hip, spine, forearm, or shoulder).

Who Should Use This Tool?

FRAX is designed for adults between the ages of 40 and 90. It is most often used for people who may have weak bones but have not yet been treated for osteoporosis. Doctors, nurses, and patients can all use this tool to start a conversation about bone health. If you are also interested in assessing other long-term health risks, consider tools like our ASCVD Risk Calculator for cardiovascular disease or the Framingham Risk Calculator for heart disease risk.

How Does FRAX Work?

The calculator looks at several things that raise your chance of breaking a bone. These include your age, sex, weight, height, and country. It also asks about seven clinical risk factors:

  • Previous fracture — Have you broken a bone as an adult from a minor fall or less?
  • Parent hip fracture — Did either of your biological parents break a hip?
  • Current smoking — Do you smoke tobacco right now?
  • Glucocorticoid use — Have you taken oral steroid pills (like prednisone) for 3 months or more?
  • Rheumatoid arthritis — Has a doctor told you that you have this joint disease?
  • Secondary osteoporosis — Do you have a condition strongly linked to bone loss, such as type 1 diabetes or untreated thyroid disease?
  • Alcohol (3+ units per day) — Do you drink 3 or more alcoholic drinks each day?

You can also enter a bone density (BMD) score from a DXA scan of the femoral neck. This is the narrow part of your thigh bone near the hip joint. Adding this score makes the result more accurate, but the calculator still works without it. When no BMD is available, the tool uses your BMI as a proxy for bone density.

Understanding Your Results

After you fill in your information, the tool gives you two numbers. Each is a percentage chance of breaking a bone in the next 10 years.

  • Hip fracture risk — A result of 3% or higher is generally considered the point where treatment should be discussed.
  • Major osteoporotic fracture risk — A result of 20% or higher is the common treatment threshold in many guidelines.

These thresholds come from guidelines used in the United States. Other countries may use different cutoff numbers. Your doctor can tell you which threshold applies to you.

Bone health is just one part of your overall wellness picture. You may also want to check your body fat percentage, review your waist-to-hip ratio, or assess your cardiovascular disease risk for a more complete view of your health. Maintaining a healthy caloric intake and monitoring calcium levels also play an important role in keeping bones strong. For a broader perspective on longevity, you might also explore our Life Expectancy Calculator.

Important Limitations

This calculator gives an estimate, not a diagnosis. It does not replace a visit with your doctor. FRAX does not account for dose effects — for example, it treats all steroid use the same whether the dose is low or high. It also does not include fall history or lumbar spine BMD. Fall risk can be influenced by balance and functional ability, which clinicians sometimes evaluate with tools like the Berg Balance Calculator or the Tinetti Calculator. Always share your results with a healthcare provider so they can give you advice based on your full medical history.

Formulas used

Body Mass Index (BMI)
\text{BMI} = \frac{W_{\text{kg}}}{\left(\frac{H_{\text{cm}}}{100}\right)^{2}}
Femoral Neck T-score from BMD
T = \frac{\text{BMD} - 0.858}{0.120}
BMI Adjustment (when BMD not available)
\text{adj}_{\text{hip}} = e^{-0.08\,(\text{BMI}-25)}, \quad \text{adj}_{\text{MOF}} = e^{-0.03\,(\text{BMI}-25)}
BMD T-score Adjustment (when BMD available)
\text{adj}_{\text{hip}} = 2^{-T}, \quad \text{adj}_{\text{MOF}} = 1.5^{-T}
Baseline Cumulative Hazard
H_{0} = -\ln\!\left(1 - \frac{P_{\text{base}} \times f_{\text{region}}}{100}\right)
10-Year Fracture Probability
P = \left(1 - e^{-\,H_{0}\;\times\;\prod RR_{i}\;\times\;\text{adj}}\right) \times 100\%

Frequently asked questions

What does FRAX stand for?

FRAX stands for Fracture Risk Assessment Tool. It was made by the World Health Organization (WHO) to predict the chance of breaking a bone in the next 10 years.

Is this FRAX Calculator free to use?

Yes. This FRAX Calculator is completely free. You can use it as many times as you want without signing up or paying anything.

Do I need a DXA scan to use this calculator?

No. A DXA scan result is optional. If you do not have one, the calculator uses your BMI to estimate bone strength instead. Adding a femoral neck T-score or BMD value will make the result more accurate, but it is not required.

What is a T-score?

A T-score compares your bone density to that of a healthy 30-year-old adult. A T-score of 0 means your bones are average. A score of −1.0 to −2.5 means low bone mass (osteopenia). A score of −2.5 or lower means osteoporosis.

Why does the calculator only work for ages 40 to 90?

The FRAX model was built and tested using data from people aged 40 to 90. The math has not been validated for people outside this range, so the results would not be reliable for younger or older adults.

What is a major osteoporotic fracture?

A major osteoporotic fracture is a break at one of four sites: the hip, spine, forearm, or shoulder. These are the bones most likely to break due to weak bones from osteoporosis.

What do the risk levels low, moderate, and high mean?

Low risk means your chance of fracture is small. Moderate risk means your doctor may want to watch your bone health more closely. High risk means treatment — such as medication or lifestyle changes — should be discussed with your doctor.

What are the treatment thresholds used in this calculator?

This calculator uses two common thresholds. A 10-year hip fracture risk of 3% or more or a 10-year major osteoporotic fracture risk of 20% or more generally means treatment should be considered. Your doctor may use different cutoffs based on your country's guidelines.

Why does the calculator ask for my country?

Fracture rates differ from country to country. People in Sweden, for example, break bones more often than people in China. Selecting your country adjusts the calculation to match the fracture rates where you live.

Does sex affect fracture risk?

Yes. Women are at higher risk of fractures than men, especially after menopause. Estrogen helps keep bones strong, and estrogen levels drop significantly after menopause. The calculator uses biological sex at birth to set the correct baseline risk.

What counts as a previous fracture?

A previous fracture is any bone you broke as an adult from a minor fall or less. This includes breaks that happened without a major accident. Fractures from car crashes or other high-force events do not count.

Why does glucocorticoid use raise fracture risk so much?

Glucocorticoids (steroids like prednisone) weaken bones by slowing down the cells that build new bone and speeding up the cells that break bone down. Long-term use at doses of 5 mg or more per day is one of the strongest risk factors for fractures.

What is secondary osteoporosis?

Secondary osteoporosis means your bone loss is caused by another medical condition. Examples include type 1 diabetes, untreated hyperthyroidism, early menopause, chronic liver disease, and malabsorption disorders like celiac disease.

How much alcohol is 3 units per day?

One unit of alcohol is about 10 grams of pure alcohol. That equals roughly one standard beer, one small glass of wine, or one shot of spirits. Three units per day means three of any of these drinks daily.

What is the femoral neck and why is it measured?

The femoral neck is the narrow part of your thigh bone just below the ball of the hip joint. It is the standard site used in FRAX because hip fractures are the most serious type of osteoporotic fracture, and this area predicts hip fracture risk best.

Can I use lumbar spine BMD instead of femoral neck?

No. The FRAX model was designed to use femoral neck BMD only. Lumbar spine measurements are useful for diagnosis, but they are not validated for use in this calculator.

What if my BMD is entered in g/cm² instead of a T-score?

The calculator can accept either format. Switch to the BMD (g/cm²) input mode and enter your value. The tool will convert it to a T-score automatically using standard reference values.

Can I use this calculator if I am already on osteoporosis medication?

FRAX was designed for people who have not yet started treatment. If you are already taking osteoporosis medication, the results may not accurately reflect your current risk. Talk to your doctor about how to interpret the score in your case.

Does this calculator account for how many cigarettes I smoke?

No. FRAX only asks whether you currently smoke or not. It does not adjust for the number of cigarettes per day. Any current tobacco use counts as a "Yes."

Does this calculator consider falls?

No. FRAX does not include fall history as a risk factor. Falls are a major cause of fractures in older adults, but the model was not built to account for them. Your doctor may consider fall risk separately.

Can men use this FRAX Calculator?

Yes. FRAX works for both men and women. Men get osteoporosis too, especially after age 70. The calculator uses different baseline fracture rates for each sex to give accurate results.

How is BMI used when I do not enter bone density?

When no BMD is provided, the calculator uses your body mass index (BMI) as a stand-in. A lower BMI is linked to thinner bones and higher fracture risk. A higher BMI generally means more weight on the bones, which can be somewhat protective. This is less accurate than a real bone density measurement.

Why does rheumatoid arthritis increase fracture risk?

Rheumatoid arthritis causes chronic inflammation that speeds up bone loss. Many people with this disease also take glucocorticoids, which weaken bones further. The disease itself also reduces mobility, which can lead to more falls.

What should I do if my result shows high risk?

Share your results with your doctor. They may recommend a DXA scan if you have not had one, medications to strengthen your bones, calcium and vitamin D supplements, weight-bearing exercise, and fall prevention strategies. Do not start any treatment on your own based on this calculator alone.

How often should I recalculate my FRAX score?

There is no set rule, but many doctors suggest rechecking every 2 to 5 years, or sooner if your health changes. For example, if you start taking steroids, break a bone, or get a new DXA scan, you should recalculate.

Does a parent's hip fracture have to be on a specific side of the family?

No. A hip fracture in either your mother or father counts. It does not matter which parent had the fracture. Only hip fractures are included — other types of breaks in a parent do not apply here.

Can I print or save my results?

Yes. Click the Print Results button below the calculator. This opens your browser's print dialog, where you can print the page or save it as a PDF to share with your doctor.

Is this calculator the same as the official FRAX tool?

This calculator uses the same clinical risk factors and a similar approach to the official FRAX model developed at the University of Sheffield. However, it is an independent implementation and may differ slightly in results. For clinical decision-making, always confirm with your healthcare provider.

Does body weight alone protect against fractures?

Higher body weight puts more mechanical load on bones, which can make them stronger. However, being overweight does not eliminate fracture risk. Other factors like age, smoking, steroid use, and family history can still raise your risk significantly.

Why does the calculator show a step-by-step solution?

The step-by-step section shows the math behind your results. It helps you and your doctor understand exactly how each risk factor contributed to your final score. It also makes the calculation transparent and easy to verify.

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