Breast Cancer Risk Calculator - Estimate 5-Year Risk

📘 About the Breast Cancer Risk

Breast cancer risk can be influenced by several personal, reproductive and family-history factors.

This calculator combines selected risk factors to provide an educational estimate.

The result is not a diagnosis and should not replace an individual medical risk assessment.

🧮 Formula

Relative risk factor

Relative Risk = Biopsy Factor × Hyperplasia Factor × Menarche Factor × Birth Factor × Family Factor × Race Factor

Estimated 5-year risk

5-Year Risk = Relative Risk × Age Factor

Where

Age = current age in years
Biopsies = number of previous breast biopsies
Atypical hyperplasia = history of atypical hyperplasia
Menarche = age category at first menstrual period
First live birth = age category at first live birth
First-degree relatives = number of first-degree relatives with breast cancer

The calculator combines selected risk-factor multipliers to estimate a relative risk factor and an estimated 5-year risk.

✏️ Worked examples

Example 1

You enter
Current Age	40 years
Race / Ethnicity	White
Number of Previous Breast Biopsies	None
History of Atypical Hyperplasia	No
Age at First Menstrual Period	12-13 years
First-Degree Relatives with Breast Cancer	None
Age at First Live Birth	20-24 years

You get
Estimated 5-Year Risk	0.45%
Relative Risk Factor	1

A 40-year-old woman with no previous biopsy, no atypical hyperplasia and no first-degree relatives with breast cancer.

Try this example →

Example 2

You enter
Current Age	55 years
Race / Ethnicity	White
Number of Previous Breast Biopsies	One
History of Atypical Hyperplasia	No
Age at First Menstrual Period	12-13 years
First-Degree Relatives with Breast Cancer	One
Age at First Live Birth	20-24 years

You get
Estimated 5-Year Risk	1.31%
Relative Risk Factor	1.74

A 55-year-old woman with one previous biopsy and one first-degree relative with breast cancer.

Try this example →

🧭 How to use this calculator

What you enter

Current Age (years)This calculator is intended for women aged 35 years and older.
Race / Ethnicity
Number of Previous Breast Biopsies
History of Atypical Hyperplasia
Age at First Menstrual Period
First-Degree Relatives with Breast Cancer
Age at First Live Birth

What you get

Estimated 5-Year Risk
Relative Risk Factor

💡 Understanding Your Risk Factor

The Relative Risk Factor is a multiplier produced from the risk factors entered into the calculator.
A value of 1.00 represents the reference level used by this simplified educational calculation.
A value above 1.00 means the combination of entered factors produces a higher calculated relative risk than the reference level.
A value below 1.00 means the combination of entered factors produces a lower calculated relative risk than the reference level.
For example, a Relative Risk Factor of 1.50 means the calculated relative risk multiplier is 1.5 times the reference level used by this calculator.
The Relative Risk Factor is not the percentage chance of developing breast cancer.
The Estimated 5-Year Risk is the percentage displayed separately and should not be confused with the Relative Risk Factor.
This calculator uses a simplified educational calculation and should not be interpreted as an official clinical risk assessment.

💡 Important limitation

This is an educational risk estimate and not a diagnosis.
Risk models have limitations and may not apply to every person.
Women with strong hereditary cancer risk may require a different clinical risk assessment.
Discuss your individual breast cancer risk and screening needs with a qualified healthcare professional.

❓ Frequently asked questions

What is a breast cancer risk calculator?

A breast cancer risk calculator estimates the likelihood of developing breast cancer over a specified period using selected personal, reproductive and family-history factors.

What does the Relative Risk Factor mean?

The Relative Risk Factor is a multiplier calculated from the risk factors entered. A value of 1.00 represents the reference level used by this simplified educational calculation. Values above 1.00 indicate a higher calculated relative risk than the reference level, while values below 1.00 indicate a lower calculated relative risk.

Is the Relative Risk Factor a percentage?

No. The Relative Risk Factor is a multiplier, not a percentage. For example, 1.50 represents a multiplier of 1.5 relative to the reference level. The Estimated 5-Year Risk is displayed separately as a percentage.

What factors are included in this calculator?

The calculator considers age, race or ethnicity, previous breast biopsies, atypical hyperplasia, age at first menstrual period, age at first live birth and first-degree family history.

Does this calculator diagnose breast cancer?

No. A risk estimate does not diagnose breast cancer. Screening and diagnostic decisions should be discussed with a qualified healthcare professional.

What does the 5-year risk mean?

The 5-year risk is an estimated percentage representing the likelihood calculated by this educational model over the next five years based on the entered factors.

Can I use this result instead of seeing a doctor?

No. The result is for informational and educational purposes and should not replace an individual assessment by a qualified healthcare professional.

🩺 Breast Cancer Risk Calculator

Enter details