FRAX Calculator UK: How to Use It and What It Asks

What is the FRAX calculator?

FRAX is a tool that turns a handful of facts about you into a percentage: your probability of breaking a bone in the next 10 years.

It was, in its own description, "developed to evaluate fracture risk", and it works by integrating "the risks associated with clinical risk factors as well as bone mineral density (BMD) at the femoral neck." The underlying models "have been developed from studying population-based cohorts from Europe, North America, Asia and Australia" — the work is credited to Osteoporosis Research Ltd and associated with the University of Sheffield. FRAX / FRAXplus, Osteoporosis Research Ltd

One practical note before you go looking for it: the calculator is now reached at fraxplus.org. The older University of Sheffield web addresses redirect there, so an old bookmark will still land you in the right place.

What does the FRAX calculator ask you?

A short set of clinical risk factors — the things that shift fracture risk most, and that a person can actually answer.

The Royal Osteoporosis Society describes a fracture risk assessment as one that "takes all the different risk factors for broken bones that you may have into account", and lists them as including: Royal Osteoporosis Society

• being aged 50 or over
• experiencing menopause
• having low bone density
• breaking a bone easily
• certain medicines
• certain health conditions
• certain lifestyle factors
• your family history

On top of those, FRAX is designed to take bone mineral density at the femoral neck — the top of the thigh bone — when a scan result is available. FRAX / FRAXplus

Two of those bullet points are worth pausing on, because they are where people most often under-report themselves. "Breaking a bone easily" means a fracture from something that shouldn't have caused one — a fall from standing height, a knock. And "certain medicines" most commonly means long-term oral steroids, which is why we cover it separately in steroids and bone loss.

How do you use the FRAX calculator, step by step?

Open the official calculation tool, answer the short list of questions, leave the bone density box blank if you have never had a scan, and press calculate. The original University of Sheffield address (frax.shef.ac.uk/FRAX) now redirects to the FRAX calculation tool at fraxplus.org. The notes below follow the tool's own definitions for each field. FRAX calculation tool

1. Use the right country model. FRAX models are country-specific. The UK guideline notes that the UK FRAX model is calibrated to a majority white population, and that for people born elsewhere, using the FRAX model for their country of birth, where one exists, is appropriate. NOGG 2024, Section 3
2. Age. The tool accepts ages from 40 to 90. If you enter an age outside that range, it computes the probability at 40 or 90 respectively. FRAX calculation tool
3. Sex. Male or female.
4. Weight and height. Entered in kilograms and centimetres (or pounds and inches, using the units selector).
5. Previous fracture. Answer yes for a fracture in adult life that happened spontaneously, or from trauma that would not normally break a healthy bone. A vertebral fracture seen only on an X-ray counts too. FRAX calculation tool
6. Parent fractured hip. This asks specifically about a hip fracture in your mother or father, not any fracture.
7. Current smoking. Yes or no.
8. Glucocorticoids. Answer yes if you are currently taking oral steroid tablets, or have taken them for more than three months at a dose of prednisolone 5 mg a day or more (or the equivalent). FRAX calculation tool
9. Rheumatoid arthritis. Answer yes only if you have a confirmed diagnosis of rheumatoid arthritis. The tool's notes point out that osteoarthritis is a different condition, so a general report of "arthritis" should not be entered here.
10. Secondary osteoporosis. Answer yes if you have a condition strongly linked to osteoporosis. The tool lists examples including type 1 diabetes, osteogenesis imperfecta in adults, untreated long-standing hyperthyroidism, hypogonadism or premature menopause (before 45), chronic malnutrition or malabsorption, and chronic liver disease. FRAX calculation tool
11. Alcohol, 3 or more units a day. Answer yes if you drink three or more units daily. The tool notes that the size of a "unit" varies slightly between countries.
12. Femoral neck BMD. If you have had a DXA scan, you can enter the femoral-neck result, either as an absolute value (after selecting the scanner make) or as a T-score. If you have never had a scan, leave it blank. Any yes/no field left blank is treated as "no". FRAX calculation tool

Then calculate. The result is your 10-year probability of a major osteoporotic fracture and of a hip fracture, shown as two percentages.

What are the most common mistakes when filling it in?

Most errors come from over- or under-reporting the yes/no questions. A few to watch for, based on the tool's own definitions:

• Counting a fracture from a serious accident. FRAX is asking about fractures that happened spontaneously or from trauma that would not normally break a healthy bone, such as a fall from standing height.
• Ticking "rheumatoid arthritis" for general joint pain. Only a confirmed rheumatoid arthritis diagnosis counts.
• Forgetting past steroid courses. More than three months of steroid tablets at 5 mg prednisolone a day or more counts, not only current use.
• Entering a spine T-score. The BMD field is for the femoral neck (hip) measurement, not the lumbar spine.

The UK guideline also notes that FRAX takes no account of previous osteoporosis drug treatment, and that clinical judgement is needed to interpret its outputs. It describes adjustments for some situations the basic tool does not capture well, such as a recent fracture or high-dose steroid use. NOGG 2024, Section 3 That is one reason to treat a self-calculated result as a conversation starter with your GP rather than a final answer.

What do the results mean?

You get two percentages, and they answer two different questions.

FRAX returns "the 10-year probability of hip fracture and the 10-year probability of a major osteoporotic fracture (clinical spine, forearm, hip or shoulder fracture)." FRAX / FRAXplus

The number	What it covers
10-year major osteoporotic fracture risk	Clinical spine, forearm, hip or shoulder
10-year hip fracture risk	The hip specifically — reported separately because of its consequences

The Royal Osteoporosis Society frames the output the same way: the assessment "uses your answers to calculate your risk of breaking a bone in the next 10 years", and "The result of your assessment is given as a percentage, which shows the probability of you breaking a bone in the next 10 years." Royal Osteoporosis Society

A percentage is a population statement applied to you, not a forecast of an event. A 10-year major fracture risk of 12% does not mean something will happen; it means that of a large group of people with your profile, roughly twelve in a hundred would sustain such a fracture over a decade. What the number is genuinely good for is deciding whether to act — and that decision layer is covered in our FRAX score guide.

What should you do with your FRAX result?

Take it to your GP, because in the UK the percentage only becomes a decision once it is compared with age-dependent thresholds. The National Osteoporosis Guideline Group sorts major-fracture probabilities into low, intermediate, high and very high risk. Broadly, low risk leads to reassurance and lifestyle advice; intermediate risk to a bone density scan where practical, followed by recalculating FRAX; high risk to treatment being considered; and very high risk to treatment and consideration of referral to an osteoporosis specialist. NOGG 2024, Section 4

For what each band means in practice, see FRAX score interpretation; for the threshold rules themselves, see FRAX and NOGG treatment thresholds; and for the factors the model weighs, see how a FRAX score is calculated.

Do you need a bone density scan to use FRAX?

No — but the answer is sharper with one.

FRAX can be run without a bone density value, and "Several simplified paper versions, based on the number of risk factors are also available." FRAX / FRAXplus That is deliberate: it makes the tool usable in a GP appointment, anywhere in the world, with no equipment.

But the tool's own description is that it integrates clinical risk factors as well as bone mineral density at the femoral neck — the density value is part of the design, not an optional extra bolted on. And the Royal Osteoporosis Society notes that as part of an assessment, "If you haven't already, you may also be referred for a bone density scan." Royal Osteoporosis Society

The distinction is simple enough to hold onto:

• FRAX without a scan estimates your risk from your circumstances.
• FRAX with a scan estimates your risk from your circumstances and the actual state of your bone.

If you want to understand what that density measurement itself reports, see DEXA scan results and T-scores explained, and REMS vs DEXA for the radiation-free route to the same measurement.

FRAX or QFracture?

Both are in UK use. The Royal Osteoporosis Society names them together: you "may also hear these test being referred to as a FRAX® or QFracture® test, which are the tools doctors can use to complete the assessment." Royal Osteoporosis Society

They ask overlapping questions and both express the result as a 10-year percentage. Which one you encounter depends on your clinician and their system rather than on anything about you.