Health calculators

Breast Cancer Risk Calculator

Updated Nov 12, 2026 By Infinity Calculator Formulas Sources Medical disclaimer
Rate
Eligibility Screening
Ever diagnosed with invasive breast cancer?
Diagnosed with DCIS or LCIS?
Tested positive for a BRCA1 or BRCA2 mutation?
Radiation therapy to the chest before age 30, or for Hodgkin lymphoma at any age?
About You
Between 35 and 85 years.
Sets the incidence rates and risk-factor weights the model uses.
Ashkenazi Jewish Heritage
Measurement Units:
Feet
Inches
Reproductive & Menstrual History
Have you given birth?
Menopause status
Biopsy & Breast Density
Breast biopsy history
Breast density (BI-RADS)
Family History
Mother, sisters, or daughters.
Grandmothers, aunts, half-sisters.
Any relative with bilateral breast cancer?
Ovarian cancer in the family?
Your Estimated Risk
5-Year Risk of Invasive Breast Cancer
1.6%
Average for your age group: 1.0%
Above Average
About 2 out of 100 women with your profile are expected to develop breast cancer over the next 5 years.
Lifetime Risk (to age 90)
18.0%
Average for your age group: 11.9%
Above Average
About 18 out of 100 women with your profile are expected to develop breast cancer in their lifetime.
Risk calculated with the Gail Model, adjusted for breast density, hormone therapy, body weight and wider family history.
You vs. Average Comparison
MeasureYour RiskAverage for Age
Suggested Next Steps
Step-by-Step Solution

Introduction

This Breast Cancer Risk Calculator estimates your chance of developing invasive breast cancer over the next 5 years and over your lifetime. It uses the Gail Model, with added adjustments for breast density, hormone therapy, body weight and wider family history.

The tool asks about your age, family history, reproductive history, breast density, and other health factors. It then uses these details to calculate a risk score and compares it to the average risk for women your age. You will also see a step-by-step breakdown of how your result was calculated.

This calculator is designed for women aged 35 to 85 who have not been diagnosed with invasive breast cancer, DCIS, LCIS, or a BRCA gene mutation.6 If any of these apply to you, the tool will let you know that these models are not validated for your situation.

This tool does not diagnose cancer. It gives an estimate based on statistical models. Your actual risk may be higher or lower. Always share your results with your doctor so they can help you decide on the right screening plan for you.

How to Use Our Breast Cancer Risk Calculator

Enter your health, family, and reproductive details below. The calculator will estimate your 5-year and lifetime risk of developing invasive breast cancer and compare it to the average for your age group.

Eligibility Screening

Prior breast cancer diagnosis: Select whether you have ever been diagnosed with invasive breast cancer. If yes, this tool does not apply to you.

DCIS or LCIS diagnosis: Select whether you have been diagnosed with ductal or lobular carcinoma in situ. If yes, this tool is not validated for your situation.6

BRCA1 or BRCA2 mutation: Select whether you have tested positive for a BRCA gene mutation. If yes, you should work with a genetic counselor instead of using this tool.

Chest radiation: Select whether you had radiation therapy to the chest before age 30, or for Hodgkin lymphoma at any age. If yes, this calculator cannot give you an accurate result.

About You

Current age: Enter your age in years. You must be between 35 and 85 years old to use this calculator.

Race or ethnicity: Choose the group that best describes you. This sets the breast cancer rates and risk-factor weights used in the calculation, since breast cancer incidence and some risk factor links differ by race and ethnicity. If you choose Hispanic or Latina, you will be asked whether you were born in the US. If you choose Asian or Pacific Islander, you will be asked which group. American Indian or Alaska Native and Other or Unknown use the rates for White women.

Ashkenazi Jewish heritage: Select yes, no, or unknown. Ashkenazi Jewish ancestry is linked to a higher background rate of certain gene mutations that affect breast cancer risk.

Measurement units: Choose Imperial (feet, inches, pounds) or Metric (centimeters, kilograms) for your height and weight entries.

Height: Enter your height in feet and inches, or in centimeters if you chose metric units.

Weight: Enter your weight in pounds, or in kilograms if you chose metric units. Height and weight are used to calculate your BMI, which can affect risk after menopause.

Reproductive and Menstrual History

Age at first menstrual period: Select the age when you had your first period. An earlier start is linked to a slightly higher risk.

Have you given birth: Select yes or no. If yes, you will be asked your age at your first live birth.

Age at first live birth: If you have given birth, select the age range when you had your first baby. Having a first child at a younger age is linked to lower risk.

Menopause status: Select whether you are premenopausal, perimenopausal, postmenopausal, or unsure.

Hormone Replacement Therapy (HRT): Select whether you have never used HRT, use vaginal estrogen only, or used estrogen-only or combined estrogen-plus-progestin therapy in the past or now. If you used HRT, you will be asked for how many years. Current combined HRT raises risk the most, and the risk grows with years of use.

Biopsy and Breast Density

Breast biopsy history: Select whether you have had a breast biopsy and, if so, what the result showed. If you have had a biopsy, you will be asked how many and whether atypical cells were found.

Atypical hyperplasia (ADH or ALH): If you have had a biopsy, check this box if atypical ductal or lobular hyperplasia was found. ADH raises breast cancer risk significantly.

Number of previous biopsies: If you have had a biopsy, enter the total number. More biopsies can indicate higher risk.

Breast density (BI-RADS): Select your breast density category from your most recent mammogram report. Denser breast tissue is linked to higher risk. Choose "Not reported / Unknown" if you do not have this information.

Family History

First-degree relatives with breast cancer: Select how many of your mother, sisters, or daughters have been diagnosed with breast cancer. More affected relatives means higher risk.

Second-degree relatives with breast cancer: Select how many of your grandmothers, aunts, or half-sisters have been diagnosed with breast cancer.

Relative with bilateral breast cancer: Select yes if any family member has had breast cancer in both breasts.

Ovarian cancer in the family: Select yes if any close family member has been diagnosed with ovarian cancer. This can signal a shared genetic risk.

Your Results

Press the Calculate button to see your estimated 5-year and lifetime breast cancer risk, a comparison chart against the average for your age, a suggested action plan, and a full step-by-step breakdown of the math behind your result. Use the Reset button to clear all fields.

Breast Cancer Risk Calculator

This calculator estimates your chance of getting invasive breast cancer. It gives you two numbers: your risk over the next 5 years and your risk over your lifetime (up to age 90). It also shows how your risk compares to the average woman your age.

The tool uses the Gail Model, published in 1989 by researchers at the National Cancer Institute from four risk factors: age at menarche, age at first live birth, number of previous biopsies and number of first-degree relatives with breast cancer.2 Its invasive-cancer version was validated in 5,969 women in the Breast Cancer Prevention Trial, where the ratio of expected to observed cancers was 1.03.4 It also adjusts for factors the Gail Model leaves out: breast density, hormone therapy use, body weight after menopause, and extended family history. The body weight relative risks come from the Tyrer-Cuzick (IBIS) model, which runs family history through Bayes' theorem to estimate the chance of carrying a predisposing gene and then refines that risk with personal factors.3 The breast density factors use relative hazards by age from a study of more than a million women having mammograms.8 The hormone therapy factors use the relative risks from a pooled analysis of the worldwide evidence, by type and years of use.1 Together, these give a more complete picture of your personal risk.

What Information You Need

The calculator asks about your age, race, menstrual history, whether you have had children, breast biopsy results, breast density from a mammogram, and how many close family members have had breast or ovarian cancer. Each of these factors is known to raise or lower breast cancer risk by a measurable amount. Your height and weight are also used to compute your BMI, which influences postmenopausal risk.

Who This Tool Is For

This calculator is designed for women ages 35 to 85 who have not been diagnosed with breast cancer, DCIS, or LCIS.6 It also does not apply to women who carry a known BRCA1 or BRCA2 gene mutation, who had radiation therapy to the chest before age 30, or who had chest radiation for Hodgkin lymphoma. If any of these apply to you, your doctor or a genetic counselor can give you a better assessment.

What Your Results Mean

A higher number does not mean you will get breast cancer. It means your chance is higher than some other women. A lower number does not mean you are safe from it. The result is a statistical estimate, not a diagnosis. The American Cancer Society recommends annual MRI screening alongside mammography for women with a lifetime risk of approximately 20 to 25% or greater by family-history-based models, and recommends against it below 15%.5 Share your results with your doctor so you can make a screening plan that fits your situation. Keeping a healthy weight is one of the protective factors linked to lower breast cancer risk.9 Excess body weight raises risk mainly after menopause.

Formulas used

Gail Model Linear Predictor 2
LP = \beta_{\text{men}} \, c_{\text{men}} + \beta_{\text{biop}} \, c_{\text{biop}} + \beta_{\text{AFLB}} \, c_{\text{AFLB}} + \beta_{\text{rel}} \, c_{\text{rel}} + \beta_{\text{int}} \left( c_{\text{AFLB}} \cdot c_{\text{rel}} \right) + \beta_{\text{biop,50}} \, c_{\text{biop}} \, I(t \ge 50)
Gail Relative Risk 7
RR = e^{\,LP} \times AH
Age-Specific Breast Cancer Hazard 7
\lambda_1(t) = h_1(t) \times (1 - AR) \times RR
Absolute Risk with Competing Mortality (Gail)
R = \sum_{t=a}^{a+n-1} \frac{\lambda_1(t)}{\lambda_1(t)+\lambda_2(t)} \left(1 - e^{-(\lambda_1(t)+\lambda_2(t))}\right) \exp\!\left(-\sum_{u < t}\left[\lambda_1(u)+\lambda_2(u)\right]\right)
Adjustment Multiplier
M(t) = f_{\text{density}}(t) \times f_{\text{HRT}} \times f_{\text{BMI}} \times f_{\text{2nd-deg}} \times f_{\text{ovarian}} \times f_{\text{bilateral}} \times f_{\text{Ashkenazi}}
Final Adjusted Risk
R_{\text{final}} = \sum_{t=a}^{a+n-1} \frac{M(t)\lambda_1(t)}{M(t)\lambda_1(t)+\lambda_2(t)} \left(1 - e^{-(M(t)\lambda_1(t)+\lambda_2(t))}\right) \exp\!\left(-\sum_{u < t}\left[M(u)\lambda_1(u)+\lambda_2(u)\right]\right)
Body Mass Index
BMI = \frac{703 \times W_{\text{lb}}}{H_{\text{in}}^{\,2}} = \frac{W_{\text{kg}}}{\left(\dfrac{H_{\text{cm}}}{100}\right)^{2}}

Frequently asked questions

What is the Gail Model?

The Gail Model is a math tool made by the National Cancer Institute. It uses your age, race, family history, biopsy results, and reproductive history to estimate your chance of getting breast cancer. It was published in 1989, fitted to Breast Cancer Detection Demonstration Project data with separate models for women under and over 50.2 Its invasive-cancer version was validated in 5,969 women in the Breast Cancer Prevention Trial.4

What is the Tyrer-Cuzick model?

The Tyrer-Cuzick model (also called the IBIS model) looks at extra risk factors that the Gail Model does not cover on its own. Its published version adds extended family history, age at menopause, height and body mass index, but it does not include breast density or hormone therapy.3 This calculator uses only its body mass index relative risks, after menopause. The published model also works differently, running family history through Bayes' theorem to estimate the chance of carrying a predisposing gene.

What does 5-year risk mean?

Your 5-year risk is the chance that you will develop invasive breast cancer within the next 5 years. For example, a 5-year risk of 2% means that about 2 out of 100 women with your same profile would be expected to get breast cancer in that time.

What does lifetime risk mean?

Lifetime risk is your estimated chance of developing invasive breast cancer from your current age up to age 90. It covers a much longer time period than the 5-year risk, so the number is usually higher.

What is breast density and how do I find mine?

Breast density describes how much fibrous and glandular tissue you have compared to fatty tissue. It is rated on a scale from A (almost entirely fatty) to D (extremely dense).8 You can find your breast density category on your mammogram report. If you have never had a mammogram or your report does not list it, choose Not reported / Unknown.

Why does breast density affect my risk?

Women with dense breast tissue (BI-RADS C or D) have a higher chance of developing breast cancer than women with fatty breast tissue.8 Dense tissue also makes it harder to spot tumors on a mammogram. That is why breast density is an important factor in risk calculations. In one large study, the relative hazard for extremely dense breasts, compared with scattered density, fell from 1.97 at age 40 to 1.53 at age 70.8 The calculator uses these relative hazards by age, compared with the average mix of densities, so a woman with scattered density (B) gets a factor of about 0.8 to 0.9.

What is atypical ductal hyperplasia (ADH)?

ADH is a condition found on a breast biopsy. It means some cells in the milk ducts look abnormal but are not cancer. Having ADH raises your breast cancer risk significantly. If a biopsy found ADH or atypical lobular hyperplasia (ALH), check the atypical hyperplasia box in the calculator to get a more accurate result.

Does hormone replacement therapy increase breast cancer risk?

Yes. In a pooled analysis of the worldwide evidence, combined estrogen-plus-progestin HRT raised breast cancer risk more than estrogen-only therapy, and the risk grew steadily with duration of use.1 Some excess risk lingers for years after stopping. Vaginal estrogen on its own was not linked to a higher risk.1 The calculator uses that analysis's relative risks for current and past use, by type and years of use, compared with women who never used HRT. For example, current combined HRT used for 1 to 4 years has a relative risk of 1.60, and for 15 years or more 2.51.1 Vaginal estrogen alone is counted as no added risk.

Why does my weight matter for breast cancer risk?

After menopause, extra body fat can raise estrogen levels, which increases breast cancer risk. The calculator uses your height and weight to figure out your BMI. If you are postmenopausal, the tool applies the Tyrer-Cuzick model's BMI relative risks, from 1.0 below a BMI of 21 to 1.32 above 27.3 Compared with the average woman, a BMI under 21 lowers your score a little and a BMI of 25 or more raises it.

What counts as a first-degree relative?

A first-degree relative is your mother, a sister, or a daughter.6 These are the closest blood relatives. Having one or more first-degree relatives with breast cancer raises your own risk. The calculator asks how many of these relatives have been diagnosed.

What counts as a second-degree relative?

A second-degree relative includes grandmothers, aunts, and half-sisters. They share less DNA with you than first-degree relatives, but their cancer history still affects your risk. The calculator applies a smaller adjustment for second-degree relatives compared to first-degree ones.

Is a high risk score the same as a cancer diagnosis?

No. A high risk score does not mean you have cancer or that you will get cancer. It means your chance is higher than average based on your risk factors. Many women with high scores never develop breast cancer. The result is a statistical estimate, not a diagnosis.

What should I do if my lifetime risk is 20% or higher?

The American Cancer Society recommends annual breast MRI in addition to mammography for women with a lifetime risk of approximately 20 to 25% or greater, as estimated by models largely dependent on family history.5 You should share your results with your doctor. Ask your doctor whether risk-reducing medication is right for you. Tamoxifen and raloxifene are FDA-approved to reduce breast cancer risk in women at higher-than-average risk, and raloxifene is used only after menopause.9

Can I lower my breast cancer risk?

Some risk factors like age and family history cannot be changed. But you can lower your risk by keeping a healthy weight, staying active and limiting alcohol.9 Combined hormone therapy also raises risk, and the excess grows with years of use.1 Talk to your doctor about steps that make sense for your situation.

Why does age at first period affect risk?

Starting your period at a younger age means your body is exposed to estrogen for a longer time over your life. Longer estrogen exposure is linked to a higher chance of breast cancer. That is why the calculator asks when your periods began.

Why does having children affect risk?

Having your first child at a younger age is linked to lower breast cancer risk. Pregnancy changes breast cells in a way that may protect them. In the Tyrer-Cuzick model, women who have never given birth have a relative risk of 1.0, against 0.67 for women who had their first child before age 20.3 That makes their risk about one and a half times as high.

What does Ashkenazi Jewish heritage have to do with breast cancer?

People of Ashkenazi Jewish descent have a higher rate of BRCA1 and BRCA2 gene mutations. These mutations are found in about 1 in 50 women of Jewish ancestry.5 The calculator applies a small adjustment if you select yes.

How often should I recalculate my risk?

It is a good idea to recalculate your risk every 1 to 2 years or whenever your health changes. For example, update your results after menopause, after a new biopsy, or if a close family member is diagnosed with breast or ovarian cancer.

Does a negative BRCA test mean I have no genetic risk?

No. A negative BRCA1/BRCA2 test means you do not carry those specific mutations. But other genes can also raise breast cancer risk. If a relative carries a known BRCA mutation and your test shows you do not have it, your risk is generally no higher than it would be without that family history. In a high-risk family with no known mutation, a negative test does not lower your risk estimate.5 If you have a strong family history, talk to a genetic counselor about broader testing.

What is the difference between DCIS and invasive breast cancer?

DCIS (ductal carcinoma in situ) is a condition in which abnormal cells are found in the lining of a breast duct and have not spread outside the duct. Invasive breast cancer means the cancer has grown beyond the ducts into nearby tissue. This calculator estimates risk for invasive breast cancer only.

Sources

  1. Collaborative Group on Hormonal Factors in Breast Cancer. Type and timing of menopausal hormone therapy and breast cancer risk: individual participant meta-analysis of the worldwide epidemiological evidence. The Lancet. 2019;394(10204):1159-1168. doi:10.1016/S0140-6736(19)31709-X. Accessed September 1, 2026.
  2. Gail MH, Brinton LA, Byar DP, Corle DK, Green SB, Schairer C, Mulvihill JJ. Projecting individualized probabilities of developing breast cancer for white females who are being examined annually. Journal of the National Cancer Institute. 1989;81(24):1879-1886. doi:10.1093/jnci/81.24.1879. Accessed September 4, 2026.
  3. Tyrer J, Duffy SW, Cuzick J. A breast cancer prediction model incorporating familial and personal risk factors. Statistics in Medicine. 2004;23(7):1111-1130. doi:10.1002/sim.1668. Accessed September 4, 2026.
  4. Costantino JP, Gail MH, Pee D, Anderson S, Redmond CK, Benichou J, Wieand HS. Validation studies for models projecting the risk of invasive and total breast cancer incidence. Journal of the National Cancer Institute. 1999;91(18):1541-1548. doi:10.1093/jnci/91.18.1541. Accessed September 4, 2026.
  5. Saslow D, Boetes C, Burke W, Harms S, Leach MO, Lehman CD, et al. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA: A Cancer Journal for Clinicians. 2007;57(2):75-89. doi:10.3322/canjclin.57.2.75. Accessed September 4, 2026.
  6. Breast Cancer Risk Assessment Calculator. Breast Cancer Risk Assessment Tool. National Cancer Institute. Accessed November 10, 2026.
  7. Breast Cancer Risk Assessment SAS Macro (Version 4, Gail Model). Division of Cancer Epidemiology and Genetics. National Cancer Institute. Accessed November 10, 2026.
  8. Tice JA, Miglioretti DL, Li C, Vachon CM, Gard CC, Kerlikowske K. Breast Density and Benign Breast Disease: Risk Assessment to Identify Women at High Risk of Breast Cancer. Journal of Clinical Oncology. 2015;33(28):3137-3143. doi:10.1200/JCO.2015.60.8869. Accessed November 10, 2026.
  9. Breast Cancer Prevention. Breast Cancer. National Cancer Institute. Accessed November 10, 2026.

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