Framingham Heart Disease Risk Calculator

Who this calculator is for

The Framingham CHD risk model was developed for community-dwelling adults without known heart disease. It performs best in people whose characteristics are similar to those in the original Framingham cohorts.

Generally appropriate users

• Adults roughly 30–74 years old.
• People without a prior heart attack, coronary stent, coronary bypass surgery, or diagnosed coronary artery disease.
• People with recent cholesterol measurements (total and HDL cholesterol).
• People who know their usual (ideally untreated) systolic blood pressure.

Situations where results may be unreliable

• Age younger than 30 or older than 74.
• Known cardiovascular disease (such as prior heart attack, stroke, or peripheral arterial disease).
• Very unusual cholesterol levels (for example, extremely high or genetically very low levels).
• Serious chronic illnesses (such as active cancer, advanced kidney or liver disease, or autoimmune conditions) that strongly affect risk but are not part of the equation.
• Populations whose background risk is very different from the original Framingham study population.

If any of these apply, discuss your situation with a clinician; a different risk tool or individualized assessment may be more appropriate.

How the Framingham risk score is calculated

The Framingham model uses a statistical method called logistic regression. Each risk factor is transformed and weighted based on how strongly it was associated with future CHD events in the Framingham cohort. The calculator then converts the combined score into a 10-year risk percentage.

Key inputs

• Age: Risk generally increases with age.
• Total cholesterol: Higher total cholesterol tends to increase risk.
• HDL cholesterol: Higher HDL is protective and lowers risk.
• Systolic blood pressure: The top number in a blood pressure reading; higher levels raise risk.
• Smoking: Current cigarette smoking significantly increases risk.
• Diabetes: Diabetes is treated as a major risk factor in many versions of the Framingham model.

In many published Framingham equations the natural logarithm (log) of each continuous variable (such as age or cholesterol) is used rather than the raw value. Each logged variable is multiplied by a coefficient, and the products are added together with additional terms for smoking and diabetes. The result is an intermediate value often called Z or the risk score.

The logistic equation

Once the intermediate score Z is calculated, the 10-year risk P is obtained using a logistic formula. In simplified mathematical form:

Here, e is the base of the natural logarithm (approximately 2.718), and Z is the weighted sum of your risk factors. When Z is higher, the resulting probability P moves closer to 1 (or 100%). When Z is lower, P approaches 0.

The specific coefficients and baseline survival used in this calculator are taken from published Framingham risk equations for coronary heart disease. The exact numbers are not needed to use the tool, but they ensure that the output matches the original research as closely as possible.

Interpreting your 10-year CHD risk

The calculator outputs a percentage that represents your estimated chance of having a coronary heart disease event (such as a heart attack or certain other coronary events) within the next 10 years, assuming your risk factors remain similar over that time.

For example, a 10-year risk of 10% means that, among 100 people with the same risk profile, about 10 might be expected to have a coronary event in the next decade, and about 90 would not. It does not mean that you personally have a 1 in 10 chance in a way that can be predicted exactly; it is a population-based estimate.

Typical risk categories

Clinical guidelines sometimes group people into risk categories to guide prevention strategies. Definitions vary by region and professional society, but a commonly used breakdown is:

• Low risk: less than 5% 10-year risk.
• Borderline risk: 5% to 7.5%.
• Intermediate risk: greater than 7.5% but less than 20%.
• High risk: 20% or higher.

Your healthcare professional may use slightly different thresholds or may weigh certain risk factors more heavily than others, depending on local guidelines and your overall health.

How results might influence next steps

The Framingham risk estimate is usually just one piece of a broader cardiovascular prevention plan. In general terms:

• Low or borderline risk: Emphasis is often on lifestyle changes such as improving diet quality, increasing physical activity, quitting smoking, maintaining a healthy weight, and moderating alcohol intake. Medication may not be needed in many people, depending on other factors.
• Intermediate risk: Clinicians may consider both lifestyle interventions and medications (such as statins for cholesterol or antihypertensives for blood pressure) after discussing benefits, risks, and patient preferences.
• High risk: More intensive risk factor management is usually recommended. This might include cholesterol-lowering medication, tighter blood pressure control, strong advice and support to stop smoking, and close follow-up.

These are general concepts, not rules. Actual treatment decisions must be made by you and a qualified clinician who can consider your full medical history, exam findings, lab results, and preferences.

Worked example: from inputs to interpretation

To make the output easier to understand, consider a hypothetical example. Imagine a 55-year-old person with the following risk profile:

• Age: 55 years
• Total cholesterol: 210 mg/dL
• HDL cholesterol: 45 mg/dL
• Systolic blood pressure: 135 mmHg
• Smoker: Yes
• Diabetes: No

When these values are entered into the calculator, the underlying equation converts each number (often using natural logarithms), multiplies by a coefficient, adds the smoking term, and produces an intermediate score Z. That score is then plugged into the logistic formula shown earlier to yield a 10-year risk percentage.

Suppose the resulting estimate is about 15%. This would place the person in an intermediate-risk category in many guideline systems. A clinician might then:

• Discuss the strong benefits of smoking cessation.
• Review diet, exercise, and weight management strategies.
• Consider whether cholesterol-lowering medication is appropriate.
• Evaluate blood pressure over time and decide if treatment is needed.

The goal is not only to lower the percentage, but to reduce the actual chance of heart disease by treating modifiable risk factors.

Comparison: Framingham vs other cardiovascular risk tools

Several risk calculators are used in practice. They share similar inputs but differ in the populations and outcomes they were designed for. The table below summarizes some broad contrasts.

Different health systems and guidelines may prefer one tool over another. Your clinician can explain which calculator they use and why it is appropriate in your situation.

Limitations and assumptions

Like all predictive models, the Framingham CHD risk equation has important limitations. Understanding these helps you interpret your result more realistically.

• Population-specific data: The model is based largely on White adults from one US town during specific time periods. Risk may be overestimated or underestimated in other ethnic groups, in non-US populations, or in settings with different background rates of CHD.
• Age range: The equation was validated mainly in adults aged 30–74. Using it outside this range may produce less reliable estimates.
• No prior cardiovascular disease: The tool is intended for people without known CHD or other major cardiovascular events. If you already have disease, your risk is generally high by definition, and different tools or clinical judgment are used.
• Limited number of risk factors: Important contributors such as family history, chronic inflammatory conditions, kidney disease, mental stress, diet quality, physical activity, and socioeconomic factors are not directly included.
• Assumes relatively stable risk factors: The 10-year estimate assumes your risk profile does not change dramatically. In reality, risk can change if you start or stop smoking, begin medications, lose weight, or develop new conditions.
• Measurement error: Cholesterol and blood pressure levels can vary from day to day and between laboratories or devices. A single measurement may not represent your long-term levels.
• Not a clinical decision rule by itself: Guidelines typically recommend using risk calculators together with clinical judgment, patient values, and sometimes additional tests (for example, coronary artery calcium scoring) for borderline or intermediate-risk cases.

This calculator is for informational and educational purposes only. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed healthcare professional before making decisions about medications or other interventions.

Frequently asked questions

Can I use this calculator if I take blood pressure medication?

Many versions of the Framingham equation were originally developed using untreated blood pressure levels. If you are already on blood pressure medication, the calculated risk may not perfectly match the original study conditions. Some clinicians use the average treated systolic blood pressure; others may estimate what your pressure would be without treatment. Interpret the result cautiously and review it with your clinician.

What if I already had a heart attack or stent?

If you have known coronary artery disease or have already had a heart attack, stent, or bypass surgery, you are usually considered high risk regardless of your Framingham score. This calculator is not intended for secondary prevention (people with established cardiovascular disease). Your care team will use different tools and guidelines tailored to your situation.

Is this accurate for people younger than 30 or older than 74?

No. The Framingham CHD risk equations were not designed for very young adults or for older adults beyond about 74 years. For younger people, lifetime risk and family history may be more informative; for older people, age alone often places them in higher risk categories. Ask your clinician which approach is best for you.

How often should I recalculate my risk?

Risk does not change overnight, but it can change over months to years as cholesterol, blood pressure, lifestyle, and medical conditions evolve. Many people reassess their risk when they have new lab results, when starting or adjusting treatment, or every one to five years as part of preventive care.

What can I do to lower my risk?

While some factors such as age and genetics cannot be changed, several powerful steps can reduce your risk of coronary heart disease. These include not smoking, maintaining a healthy weight, eating a heart-healthy diet, staying physically active, managing blood pressure, and treating high cholesterol or diabetes when indicated. Work with a healthcare professional to create a prevention plan that fits your life and medical history.

References and further reading

The Framingham risk equations are based on decades of peer-reviewed research. Key sources include:

• Wilson PWF, D'Agostino RB, Levy D, et al. Prediction of coronary heart disease using risk factor categories. Circulation. 1998;97(18):1837–1847.
• D'Agostino RB Sr, Vasan RS, Pencina MJ, et al. General cardiovascular risk profile for use in primary care: the Framingham Heart Study. Circulation. 2008;117(6):743–753.
• Relevant national and international cardiovascular prevention guidelines that incorporate or discuss Framingham-based risk scores.

Where possible, discuss your results with a clinician who is familiar with these or more recent risk models and who can relate them to the guidelines used in your health system.