" The halls.md detailed breast cancer risk calculator offers a choice of two calculation methods, called 'Gail model 1' and 'NSABP model 2' (National Surgical Adjuvant Breast and Bowel Project)."

The "summary relative risk" is calculated on the basis of responses to six questions: number of sisters, daughters or mother who had breast cancer; number of benign breast biopsies; age at first menstrual cycle; age when first gave birth; current age; race.

Six optional extra relative risk factors may then also be taken into account in the risk calculation: " mammographic density, age-specific tamoxifen effect, dose-specific alcohol effect, age-specific correction factors to adjust for Black race, presence of LCIS on a biopsy, and oral contraceptives effects".

A considerable amount of background and technical information on the tool, including references, is provided on the halls.md site.